We provide nuclei practice exercises, instructions, and a learning material that allows learners to study outside of the classroom. We focus on nuclei skills mastery so, below you will get all questions that are also asking in the competition exam beside that classroom.

#### List of nuclei Questions

Question No | Questions | Class |
---|---|---|

1 | 43. The percentage of quantity of a radioactive material that remains after 5 half-lives will be (a) 31% (b) 3.125% (c) 0.3% (d) 1% | 12 |

2 | The activity of radioactive sample is measured as 9750 counts per minute at ( t=0 ) and as 975 counts per minute at ( t=5 ) minutes, the decay constant is approximately A . 0.922 per minute B. 0.270 per minute c. 0.461 per minute D. 0.39 per minute | 12 |

3 | Ten grams of ( C o^{57} ) kept in open container beta-decays with half life of 270 days. The weight of the material in container after 540 days will be very nearly. ( A cdot 10 g m ) B. ( 5 mathrm{gm} ) c. ( 2.5 mathrm{gm} ) D. ( 1.25 mathrm{gm} ) | 12 |

4 | Draw a diagram of nuclear power reactor and label the parts. | 12 |

5 | Complete the table given below: ( begin{array}{llll}text { Element } & begin{array}{l}text { Atomic } \ text { mass }end{array} & begin{array}{l}text { Molecular } \ text { mass }end{array} & begin{array}{l}text { Atomicit } \ text { number }end{array} \ text { Chlorine } & 35.5 & 71 & – \ text { Ozone } & – & 48 & 3 \ text { Sulphur } & 32 & – & 8 \ text { Nitrogen } & 14 & – & 2end{array} ) | 12 |

6 | With the help of a suitable example and an equation, explain the term pair production | 12 |

7 | Fusion reaction takes place at very high temperature because A. atoms are ionised at high temperatures B. molecules breakup at high temperature C . nuclei break up at high temperature D. kinetic energy is high enough to overcome repulsion between nuclei | 12 |

8 | Mass equivalent to the energy ( 931 mathrm{MeV} ) is: ( mathbf{A} cdot 6.02 times 10^{-27} k g ) В. ( 1.662 times 10^{-27} k g ) c. ( 16.66 times 10^{-27} k g ) D. ( 16.02 times 10^{-27} mathrm{kg} ) | 12 |

9 | Hydrogen bomb is based on the principle of | 12 |

10 | In India, a nuclear power plant is located in A. Rampur B. Tarapur c. sahranpur D. Kanpur | 12 |

11 | In the radioactive change, ( stackrel{A}{Z} boldsymbol{P} longrightarrow_{Z+1}^{A} boldsymbol{Q} longrightarrow_{Z-1}^{A-4} boldsymbol{R} longrightarrow_{Z-1}^{A-4} boldsymbol{S} ) the radiations emitted in sequence are: ( mathbf{A} cdot alpha, beta, gamma ) в. ( beta, alpha, gamma ) c. ( gamma, alpha, beta ) D. ( beta, gamma, alpha ) | 12 |

12 | Energy released in nuclear reaction is related to mass by A ( . E=1 / 2 m v^{2} ) B . ( E=m v^{2} ) ( mathbf{c} cdot E=m c^{2} ) D. ( E=1 / 2 m c^{2} ) | 12 |

13 | Problem associated with nuclear power plants is A. Emmission of hazardous waste B. Disposal of radioactive waste c. Thermal pollution D. All of the above | 12 |

14 | The average ( K E ) of molecules in a gas at temperature ( T ) is ( frac{3}{2} k T . ) Find the temperature at which the average KE of molecules equal to binding energy of its atoms. A . ( 1.05 times 10^{5} K ) В. ( 1.05 times 10^{4} K ) c. ( 1.05 times 10^{3} K ) D. none of these | 12 |

15 | The half life of a radioactive substance is 20 minutes. The time taken between ( 50 % ) decay and ( 87.5 % ) decay of the substance will be A . 30 minutes B. 40 minutes c. 25 minutes D. 10 minutes | 12 |

16 | Number of neutrons in heavy hydrogen atom is : ( mathbf{A} cdot mathbf{0} ) B. ( c cdot 2 ) ( D ) | 12 |

17 | A certain substance decays to ( frac{1}{32} ) of its initial activity in 25 days. The half life is: A. 1 day B. 3 days c. 5 days D. 7 days | 12 |

18 | Which would be larger : an atomic mass unit based on the current standard or one based on the mass of a Be- 9 atom ( operatorname{set} ) at exactly 9 amu? | 12 |

19 | The half life of a radioactive nucleus is 50 days.The time interval ( left(t_{2}-t_{1}right) ) between the time ( t_{2} ) when ( frac{2}{3} ) of it has decayed and the time ( t_{1} ) when ( frac{1}{3} ) of it had delayed is- A. 50 days B. 60 days c. 15 days D. 30 days | 12 |

20 | In a nuclear reactor, what is the function of the control rods? | 12 |

21 | ( _{3} L i^{7}+_{1} H^{2} rightarrow_{4} B e^{8}+_{o} n^{1}+Q ) Mass of ( _{3} L i^{7}=7.01823 a m u ) Mass of ( _{1} H^{2}=2.01474 a m u ) Mass of ( _{4} B e^{8}=8.00785 a m u ) Mass of ( _{o} n^{1}=1.00899 a m u ) Then, the value of Q is A. 5 MeV в. ( 10 mathrm{MeV} ) c. 15 MeV D. | 12 |

22 | A radioactive sample can decay by two different processes. The half-life for the first process is ( T_{1} ) and that for the second process is ( T_{2} ). The effective half- life ( T ) of the radioactive sample is A ( cdot T=T_{1}+T_{2} ) в. ( frac{1}{T}=frac{1}{T_{1}}+frac{1}{T_{2}} ) c. ( T=frac{T_{1}+T_{2}}{T_{1} T_{2}} ) D. ( T=frac{T_{1}-T_{2}}{T_{1} T_{2}} ) | 12 |

23 | 65. On an average, a neutron loses half of its energy per collision with a quasi-free proton. To reduce a 2 MeV neutron to a thermal neutron having energy 0.04 eV, the number of collisions required is nearly (a) 50 (b) 52 (c) 26 (d) 15 | 12 |

24 | Statement-I : Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion and Statement-11: For heavy nuclei, binding energy per nucleon increases with increasing Z. while for light nuclei it decreases with increasing Z. A. Both the statements are true and Statement 2 is the correct explanation for Statement B. Both the statements are true but Statement 2 is not the correct explanation for Statement 1 c. statement 1 is true but Statement 2 is false D. Statement1 is false but Statement 2 is true | 12 |

25 | The electron present in excited state of ( H e^{oplus text { ion shows separation on collision }} ) with an electron having 2.5 eV energy. What will be the minimum value of ( n ) for this electrons of ( H e^{oplus} ) ion? A .4 B. 5 ( c cdot 6 ) D. 3 | 12 |

26 | Determine the values of ( x ) and ( y ) A .2,5 B . 2,4 ( mathrm{c} cdot 1,5 ) D. 1,3 | 12 |

27 | In a thermo-nuclear reaction, ( 10^{-3} mathrm{Kg} ) of Hydrogen is converted into ( 0.99 times 10^{-3} ) kg of Helium. If the efficiency of the generator is ( 50 % ), the electrical energy generated in KWH is A ( cdot 10^{5} ) B . ( 1.5 times 10^{5} ) c. ( 1.25 times 10^{5} ) D. ( 1.3 times 10^{5} ) | 12 |

28 | Suppose India had a target of producing by ( 2020 mathrm{AD}, 200,000 mathrm{MW} ) of electric power, ten percent of which was to be obtained from nuclear power plants. Suppose we are given that, on an average, the efficiency of utilization (i.e. conversion to electric energy) of thermal energy produced in a reactor was ( 25 % . ) How much amount of fissionable uranium would our country need per year by ( 2020 ? ) Take the heat energy per fission of ( ^{235} U ) to be about ( 200 mathrm{MeV} ) | 12 |

29 | The end product of the decay of ( _{90}^{232} ) Th is ( 208 mathrm{Pb} ). The number of alpha and beta 22 particles emitted are A. 3,3 в. 6,4 c. 6,0 D. 4,6 | 12 |

30 | Which of the following is/are example(s) of isotones? ( A cdot_{6} C^{12} ) and ( _{6} C^{13} ) B . ( _{11} N a^{23} ) and ( _{12} M g^{23} ) ( mathbf{c} cdot_{14} S i^{30} ) and ( _{16} S^{32} ) D・ ( _{83} B i^{210} ) and ( _{84} P o^{21} ) | 12 |

31 | In a radioactive decay, an element ( _{Z} X^{A} ) emits four ( alpha ) -particles, three ( beta ) -particles and eight gamma photons. The atomic number and mass number of the resulting final nucleus are A. ( Z-11, A-16 ) в. ( Z-5, A-13 ) c. ( Z-5, A-16 ) D. ( Z-8, A-13 ) | 12 |

32 | In a nuclear reactor the number of ( U^{235} ) nuclei undergoing fissions per second is ( 4 times 10^{20} . ) If the energy released per fission is ( 250 M e V ), the total energy released in 10 hours is ( left(1 e V=1.6 times 10^{-19} Jright) ) A ( .576 times 10^{6} J ) В. ( 576 times 10^{12} J ) c. ( 576 times 10^{15} J ) D. ( 576 times 10^{18} J ) | 12 |

33 | A radio active element has a half life of 20 min.The time that should elapse before the element is reduced ( 1 / 8 ) th of the original mass is: A. 40 min B. 60 min c. 80 min D. 160 min | 12 |

34 | Q Type your question rate of formation of ( Y ) against time ( t ) will be ( A ) B. ( c ) ( D ) | 12 |

35 | 4. Which of the following cannot be emitted by a radioactive substance enduring its decay? (a) electrons (b) protons (c) neutrinos (d) helium nuclei (AIEEE 2003) | 12 |

36 | Which of the following doesn’t affected by both electrical field and magnetic field? A. Alpha rays B. Beta rays c. Gamma rays D. All of the above | 12 |

37 | If mass-energy equvalence is taken into account, when water is cooled to form ice, the mass of ater should A. Increase B. Remain unchanged c. decrease D. First increase and then decrease | 12 |

38 | Mass of atom expressed in atomic mass unit is : A. atomic mass B. molecular mass c. atomic number mass D. None of the above | 12 |

39 | A nucleus ( _{z}^{A} X ) emits an ( alpha ) -particle with velocity ( v . ) The recoil speed of the daughter nucleus is: A. ( frac{A-4}{4 v} ) в. ( frac{4 v}{A-4} ) ( c ) D. ( frac{v}{4} ) | 12 |

40 | The atomic number of an element is more important to the chemist than its relative atomic mass. Why? | 12 |

41 | The binding energies energy per nucleon for ( C^{12} ) is ( 7.68 M e V ) and that for ( C^{13} ) is 7.5 MeV.The energy required to remove a neutron from ( C^{13} ) is A. ( 5.34 mathrm{MeV} ) B. 5.5 MeV c. ( 9.5 mathrm{MeV} ) D. ( 9.34 mathrm{MeV} ) | 12 |

42 | Which of the following pairs are isotopes? A. Oxygen and Ozone B. Ice and Steam c. Nitric oxide and Nitrogen dioxide D. Hydrogen and Deuterium | 12 |

43 | Calculate the mass defect. A . 2.014 и в. 1.0087 и c. ( 0.01876 u ) D. 0.0234 и | 12 |

44 | 35. Half-lives of two radioactive elements A and B are 20 minutes and 40 minutes, respectively. Initially, the samples have equal number of nuclei. After 80 minutes, the ratio of decayed numbers of A and B nuclei will be (a) 1:16 (b) 4:1 (c) 1:4 od (d) 5:4 (JEE Main 2016) | 12 |

45 | For a first order radio-active decay, the half-life period is: A. dependent on the square of the initial concentration B. dependent on first power of initial concentration C. dependent on the square root of initial concentration D. independent on initial concentration | 12 |

46 | Fission of nuclei is possible because binding energy per nucleon in them: A. increases with mass number at low mass number B. increases with mass number at high mass number c. decreases with mass number at low mass number D. decreases with mass number at high mass number | 12 |

47 | The missing particle in the reaction: ( underset{99}{253} boldsymbol{E} boldsymbol{s}+_{2}^{4} boldsymbol{H} boldsymbol{e} rightarrow_{101}^{256} boldsymbol{M} boldsymbol{d}+ ) A. deuteron B. proton c. neutron D. ( beta ) – particle | 12 |

48 | In the options below which one of the isotope of the uranium can cause fission reaction? A ( cdot U_{234} ) B. ( U_{235} ) c. ( U_{23} ) D. ( U_{238} ) | 12 |

49 | In nuclei with mass number greater than ( 20, ) the average binding energy is: ( mathbf{A} cdot 8 M e V ) в. 0.8 Ме ( V ) ( c .80 M e V ) D. ( 0.08 mathrm{MeV} ) | 12 |

50 | In a nuclear reactor, what is the function of the moderator? | 12 |

51 | Consider the following decay series: ( boldsymbol{A} longrightarrow boldsymbol{B} longrightarrow boldsymbol{C} longrightarrow boldsymbol{D} ) Where, ( A, B ) and ( C ) are radioactive elements with half lives of 4.5 sec, 15 days and 1 sec respectively and ( D ) is non-radioactive element. Starting with 1 mole of ( A ), the number of moles of ( A ) ( B, C ) and ( D ) left after 30 days are: A. One mole of ( D ) and none of ( A, B ) or ( C ) B. ( 3 / 4 ) mol of ( B, 1 / 4 ) mol of ( D ) and none of ( A ) or ( C ) C. ( 1 / 4 ) mol of ( B, 3 / 4 ) mol of ( D ) and none of ( A ) or ( C ) D. ( 1 / 2 ) mol of ( B, 1 / 4 ) mol of ( C, 1 / 4 ) mol of ( D ) and none of ( A ) E . ( 1 / 4 ) mol of each ( A, B, C ) and ( D ) | 12 |

52 | A radioactive nucleus undergoes a series of decays according to the sequence ( boldsymbol{A} stackrel{boldsymbol{beta}}{rightarrow} boldsymbol{A}_{mathbf{1}} stackrel{boldsymbol{alpha}}{rightarrow} boldsymbol{A}_{2} stackrel{boldsymbol{alpha}}{rightarrow} boldsymbol{A}_{mathbf{3}} ) If the mass number and atomic number of ( A_{3} ) are 172 and 69 respectively, then the mass number and atomic number of A is A. 56,23 B. 180,72 c. 120,52 D. 84,38 | 12 |

53 | If 1 and 2 are the wavelengths of characteristic X-ray and gamma rays respectively, then the relation between them is : ( A cdot 12 ) D. None of these | 12 |

54 | What is the disintegration constant of a radioactive element, if the number of its atoms diminishes by ( 18 % ) in 24 h? A. ( 2.1 times 10^{-3} / s ) в. ( 2.1 times 10^{5} / s ) C ( .22 times 10^{6} / s ) D. ( 22 times 10^{-6} / s ) | 12 |

55 | The excitation energy of a hydrogen like ion to first excited state is ( 40.8 mathrm{eV} ). The energy needed to remove the electron from the ion the ground state is A. 54.4 ev B. 62.6 ev c. ( 72.6 mathrm{ev} ) D. 58.6 ev. | 12 |

56 | ( 9_{2} U^{235} ) nucleus absorbs a neutron and disintegrates into ( _{54}^{92} X e^{139},_{38} S r^{94} ) and ( boldsymbol{X} ) A. 3 neutrons B. 2 neutrons c. – ( alpha ) particle D. – ( beta ) particle | 12 |

57 | An element ( boldsymbol{X} ) decays first by positron emission and then ( 2 alpha ) particles are emitted in succession. If the product nucleus has mass number 229 and atomic number 89 then the mass number and atomic number of element ( boldsymbol{X} ) are A .237,93 в. 237,94 c. 238,93 D. 237,92 | 12 |

58 | Nuclear fission and fusion can be explained on the basis of Einstein’s: A. Theory of relativity B. Specific heat equation c. Mass-energy relation D. Photoelectric equation | 12 |

59 | The essential distinction between ( X ) rays and ( gamma ) -rays is that the ( gamma ) -rays: A. have greater ionizing power than ( x ) -rays B. emanate from nucleus, white X-rays emanate from outer part of the atom C. have smaller wave-length than X-rays D. none of the above | 12 |

60 | 71. The initial activity of a certain radioactive isotope was measured as 16000 counts min-!. Given that the only activity measured was due to this isotope and that its activity after 12 h was 2100 counts min, its half-life, in hours, is nearest to [Given loge (7.2) = 2] (a) 9.0 (b) 6.0 (c) 4.0 (d) 3.0 | 12 |

61 | 3. Beta rays emitted by a radioactive material are a (a) electromagnetic radiation (b) the electrons orbiting around the nucleus (c) charged particles emitted by nucleus (d) neutral particles (AIEEE 2002) | 12 |

62 | The half-life of tritium is 12.5 years What mass of tritium of initial mass 64 mg will remain undecayed after 50 years? A. ( 32 mathrm{mg} ) B. ( 8 mathrm{mg} ) c. ( 16 mathrm{mg} ) D. ( 4 mathrm{mg} ) | 12 |

63 | What are isotopes and isobars? | 12 |

64 | Atomic mass of an element is: A. actual mass of one atom of the element B. relative mass of an atom of the element C . average mass of an atom of different atoms of the element D. always a whole number | 12 |

65 | 5. A radioactive sample at any instant has disintegration rate 5000 disintegrations per minute. After 5 min, the rate is 1250 integrations per minute. Then the decay constant (per minute) is (a) 0.8 In 2 (b) 0.4 In 2 (c) 0.2 In 2 (d) 0.1 In 2 (AIEEE 2003) | 12 |

66 | Which of the following are fissile isotopes? This question has multiple correct options | 12 |

67 | A radioactive element ( X ) distintegrates successively ( boldsymbol{X} stackrel{boldsymbol{beta}^{-}}{longrightarrow} boldsymbol{X}_{mathbf{1}} stackrel{boldsymbol{alpha}}{longrightarrow} boldsymbol{X}_{2} stackrel{boldsymbol{beta}^{-}}{longrightarrow} boldsymbol{X}_{mathbf{3}} stackrel{boldsymbol{alpha}}{longrightarrow} boldsymbol{X}_{mathbf{4}} ) If atomic number and atomic mass number of ( X ) are respectively 72 and ( 180, ) what are the corresponding values for ( boldsymbol{X}_{4} ? ) A .69,172 B. 69,176 c. 71,176 D. 70,172 | 12 |

68 | The fuel used in nuclear power plants is A. U-235 B. U-238 c. ( cup-236 ) D. None of the above | 12 |

69 | 10grams of a radioactive element is disintegrated to 1gram in 2.303 minutes The half-life (in minutes) of that radioactive element is: A ( cdot frac{1}{0.693} ) B. 6.93 c. 1 D. 0.693 | 12 |

70 | Identify the correct order of ( alpha, beta ) and ( gamma ) with reference to their penetrating power in decreasing order. I) ( boldsymbol{alpha} ) -ray II) ( boldsymbol{gamma} ) -ray III) ( beta ) -ray ( mathbf{A} cdot ) ॥,॥।, B. ॥,|,||| c. ।,॥,॥ D. III,,,III | 12 |

71 | The nuclei ( _{13} A l^{27} ) and ( _{14} S i^{28} ) are examples of: A. isotopes B. isobars c. isotones D. isomers | 12 |

72 | Arrange the following elements in increasing order their Half life period, Uranium, Polonium, Radon, Strontium. | 12 |

73 | Two radioactive substances ( A ) and ( B ) have decay constants ( 5 lambda ) and ( lambda ) respectively.At ( t=0, ) they have the same number of nuclei. The ratio of number of nuclei of ( A ) to those of ( B ) will be ( left(1 / e^{2}right) ) after a time: A ( .4 lambda ) B. 2lambda c. ( frac{1}{2 lambda} ) D. ( frac{1}{4 lambda} ) | 12 |

74 | 74. 238U decays with a half-life of 4.5 x 10 years, the decay series eventually ending at 206Pb, which is stable. A rock sample analysis shows that the ratio of the number of atoms of 206Pb to 238 U is 0.0058. Assuming that all the “Pb is produced by the decay of 238U and that all other half-lives on the chain are negligible, the age of the rock sample is (In 1.0058 = 5.78 x 10) (a) 38 x 108 years (b) 38 x 10 years (c) 19 x 100 years (d) 19 x 10 years 26 | 12 |

75 | Control rods in a nuclear power plant is to A. Slow the neutrons thereby controlling the fission reaction B. Shut down the reactor. c. Both (1) and (2) D. None of these | 12 |

76 | Assume that the nuclear binding energy per nucleon (B/A) versus mass number (A) is as shown in the figure. Use this plot to choose the correct choice(s) given below. This question has multiple correct options A. Fusion of two nuclei with mass numbers lying in the range of ( 1<A<50 ) will release energy B. Fusion of two nuclei with mass numbers lying in the range of ( 51<A<100 ) will release energy c. Fission of a nucleus lying in the mass range of 100 < ( A<200 ) will release energy when broken into two equal fragments D. Fission of a nucleus lying in the mass range of ( 200< ) ( A<260 ) will release energy when broken into two equal fragments | 12 |

77 | What is the mass defect and the binding energy of ( _{27} C o^{59} ) which has a nucleus of mass of ( 58.933 u ? ) ( left(boldsymbol{m}_{boldsymbol{p}}=mathbf{1 . 0 0 7 8 u}, boldsymbol{m}_{boldsymbol{n}}=mathbf{1 . 0 0 8 7 u}right) ) B. 617.914 MeV c. 17.914 Mev D. 717.914 Mev | 12 |

78 | A radioactive sample at any instant has its disintegration rate 5000 dpm. After 5 minutes, the rate is 1250 dpm.Then, the decay constant (per minute) is A ( .0 .4 ln 2 ) в. ( 0.2 ln 2 ) c. ( 0.1 ln 2 ) D. ( 0.8 ln 2 ) | 12 |

79 | The first experiment on radioactivity was done with the element | 12 |

80 | Half life of a certain radioactive substance is 6 hours. If you had ( 3.2 k g ) of this substance in the beginning, how much of it will disintegrate in one day? | 12 |

81 | kg of ( _{text {一一一一一一一一 }} ) can light up 1 bulb for ( 3 times 10^{4} ) years. A. Uranium B. Halonium c. Neutronium D. Hydronium | 12 |

82 | A radioactive element decays by parallel path as given below: ( boldsymbol{A} stackrel{lambda_{1}}{longrightarrow} boldsymbol{B} quad boldsymbol{lambda}_{1}=mathbf{1 . 8} times mathbf{1 0}^{-2} boldsymbol{s e c}^{-1} ) ( mathbf{2 A} stackrel{lambda_{2}}{longrightarrow} boldsymbol{B} quad boldsymbol{lambda}_{2}=mathbf{1 0}^{-mathbf{3}} boldsymbol{s e c}^{-mathbf{1}} ) Average life of radio-nuclide ( boldsymbol{A} ) will be: A .52 .63 sec B. 500 sec c. 50 sec D. 120 sec | 12 |

83 | State whether the given statement is True or False : Waste products emitted from nuclear power plants are very harmful. | 12 |

84 | (a) Deduce the expression, ( N= ) ( N 0 e^{-lambda} t, ) for the law of radioactive decay. (b)(i) Write symbolically the process expressing the ( beta+ ) decay of ( _{11}^{22} ) Na. Also write the basic nuclear process underlying this decay. (ii) Is the nucleus formed in the decay of the nucleus ( _{11}^{22} N a, ) an isotope or isobar? | 12 |

85 | Assume that two deuteron nuclei in the core of fusion reactor at temperature ( T ) are moving toward each other, each with kinetic energy ( 1.5 mathrm{kT} ), when the separation between them is large enough to neglect Coulomb potential energy. Also, neglect any interaction from other particles in the core. The minimum temperature T required for them to reach a separation of ( 4 x ) ( 10^{-15} m ) is in the range A . ( 1.0 times 10^{9} K<T<2.0 times 10^{9} K ) B . ( 2.0 times 10^{9} K<T<3.0 times 10^{9} K ) c. ( 3.0 times 10^{9} K<T<4.0 times 10^{9} K ) D. ( 4.0 times 10^{9} K<T<5.0 times 10^{9} K ) | 12 |

86 | For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is? A . 30 B . 20 c. 15 D. 10 | 12 |

87 | The half life for ( alpha ) -decay of uranium ( 92 U^{228} ) is ( 4.47 times 10^{8} y r . ) If a rock contains ( 60 % ) of original ( _{92} U^{228} ) atoms, then its age is ( [operatorname{take} log 6=0.778, log 2=0.3] ) A ( cdot 1.2 times 10^{7} y r ) B. ( 3.3 times 10^{8} y r ) c. ( 4.2 times 10^{9} y r ) D. ( 6.5 times 10^{9} y r ) | 12 |

88 | Inside the sun, four nuclei of hydrogen combine to form: A. two nuclei of helium B. four nuclei of helium c. one nucleus of helium D. deuterium | 12 |

89 | Initial mass of a radioactive substance is ( 3.2 mathrm{mg} ). It has a half-life of ( 4 mathrm{h} ). Find the mass of the substance left undecayed after ( 8 mathrm{h} ) | 12 |

90 | For the isotope ( _{6} C^{13}, ) the number of neutrons is: ( A cdot 6 ) B. 7 c. 19 D. 13 | 12 |

91 | Four different radioactive elements are kept in separate containers. In the beginning the container ( A ) has 200 gatom with half-life of 2 days, ( B ) has 20 g-atom with half-life of 20 days, ( C ) has 2 g-atom with half-life 200 days and ( D ) has 100 g-atoms with half-life of 10 days. In the beginning the maximum activity exhibited by the container is: A. ( a ) B. ( b ) ( c ) D. ( d ) | 12 |

92 | Consider the following statements A and B and identify the correct statements. Statement ( A: p-n ; p-p ; n-n ) forces between nucleons are not equal and charge dependent statement B : In nuclear reactor the fission reaction will be in accelerating state if the value of neutron reproduction factor is ( k>1 ) A. Both A and B are correct B. Both A and B are wrong c. A is wrong B is correct D. A is correct B is wrong | 12 |

93 | A sample of a radioactive element has a mass of ( 10 g ) at an instant ( t=0 . ) The approximate mass of this element in the sample after two mean lives is A. ( 1.35 g ) в. ( 2.50 g ) c. ( 3.70 g ) D. ( 6.30 g ) | 12 |

94 | A radioactive element has rate of disintegration 10,000 disintegrations per minute at a particular instant. After four minutes it becomes 2500 disintegrations per minute. The decay constant per minute is A ( cdot 0.2 log _{e}^{2} ) B . ( 0.5 log _{e}^{2} ) c. ( 0.6 log _{e}^{2} ) D. ( 0.8 log _{e}^{2} ) | 12 |

95 | Differentiate between half life and average life of a radioactive substance. | 12 |

96 | Rest mass of a ( beta ) particle is A ( cdot 1.6 times 10^{-19} k g ) В . ( 9.1 times 10^{-31} k g ) C. ( 2 times 10^{2} k g ) D. ( 1 times 10^{5} mathrm{kg} ) | 12 |

97 | is the energy released during nuclear reactions | 12 |

98 | Is the principle reaction responsible for the energy output of the sun: A. Gamma decay B. Nuclear fusion c. Alpha decay D. Positron emission E. Nuclear fission | 12 |

99 | 28. A certain radioactive element has half-life of 4 days. The fraction of material that decays in 2 days is (a) 1/2 (b) 1/2 (c) √2 (d) (V2 – 1)/V2 | 12 |

100 | In the nuclear reaction pictured below, what is the missing nuclide? ( _{1}^{2} boldsymbol{H}+mathbf{7}^{14} boldsymbol{N} rightarrow_{2}^{3} boldsymbol{H} boldsymbol{e}+? ) B . ( _{6}^{13} mathrm{C} ) ( mathbf{c} cdot frac{14}{7} N ) D. ( _{6}^{1} C ) E ( cdot frac{12}{6} C ) | 12 |

101 | expected to disintegrate by: A. ( alpha ) -emission B. ( beta ) -emission C. positron emission D. proton emission | 12 |

102 | Why do atomic masses of most of the elements in atomic mass units involve fraction? | 12 |

103 | 26. The half-life of a radioactive decay is x times its mean life. The value of x is (a) 0.3010 (b) 0.6930 (c) 0.6020 (d) 0.6930 | 12 |

104 | A radio nuclide ( A_{1} ) with decay constant ( lambda_{1} ) transforms into a radio nuclide ( A_{2} ) with decay constant ( lambda_{2} ). Assuming that at the initial moment, the preparation contained only the radio nuclide ( boldsymbol{A}_{mathbf{1}} ) (a) Find the equation describing accumulation of radio nuclide ( A_{2} ) with time. (b) Find the time interval after which the activity of radio nuclide ( A_{2} ) reaches its maximum value. | 12 |

105 | 54. A heavy nucleus having mass number 200 gets disintegrated into two small fragments of mass numbers 80 and 120. If binding energy per nucleon for parent atom is 6.5 MeV and for daughter nuclei is 7 MeV and 8 MeV, respectively, then the energy released in the decay will be (a) 200 MeV (b) -220 MeV (c) 220 MeV (d) 180 MeV | 12 |

106 | ( mathrm{g}_{2} U^{235} ) nucleus absorbs a neutron and disintegrates into ( _{54} X e^{139},_{38} S r^{94} ) and X. What will be the product ( X ? ) A. 2 neutrons B. 3 neutrons c. ( alpha ) -particle D. ( beta ) -particle | 12 |

107 | Statement ( 1: frac{13}{6} C ) and ( _{6}^{14} C ) are isotopes of the element carbon. Statement 2: Isotopes of an element have the same number of protons in the nucleus but have a different number of neutrons. A. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1 B. Both Statement 1 and Statement 2 are correct but Statement 2 is not the correct explanation of Statement 1. c. Statement 1 is correct but Statement 2 is not correct. D. Statement 1 is not correct but Statement 2 is correct E. Both the Statement 1 and Statement 2 are not correct | 12 |

108 | Light from a discharge tube containing hydrogen atoms falls on the surface of a piece of sodium. The kinetic energy of the fastest photoelectrons emitted from sodium is ( 0.73 e V ). The work function for sodium is ( 1.82 e V . ) The rocoil speed of emitting atom assuming it to be at rest before ionisation is (lonisation potential of hydrogen is ( 13.6 e V ) ). B . ( 1.80 mathrm{ms}^{-1} ) c. ( 8.10 m s^{-1} ) D. ( 0.81 mathrm{ms}^{-1} ) | 12 |

109 | which have the same positive kinetic energy but different masses. For this ensemble, which graph best represents the relationship between the particle’s mass and its total energy? ( A ) в. ( c ) D. | 12 |

110 | Due to ( gamma ) decay, what is the effect on neutron and proton numbers? A. Both remains constant B. Proton number increase but neutron number decreases c. Proton number decreases and neutron increases D. None of these | 12 |

111 | The kinetic energy (in keV) of the alpha particle, when the nucleus at rest undergoes alpha decay, is A. 5319 B. 5422 c. 570 D. 5818 | 12 |

112 | In gamma ray emission from a nucleus A. both the neutron number and the proton number change B. there is no change in the proton number and the neutron number C . only the neutron number changes D. only the proton number changes | 12 |

113 | A metal oxide has the formula ( X_{2} O_{3} ). It can be reduced by hydrogen to give free metal and water. ( 0.1596 g ) of metal oxide requires ( 6 m g ) of hydrogen for complete reduction. The atomic mass of metal in amu is: A . 15.58 B. 155.8 c. 5.58 D. 55.8 | 12 |

114 | 38. A sample of a radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is (a) 1.35 g (b) 2.50 g (c) 3.70 g (d) 6.30 g | 12 |

115 | 64. A B 22 C T=0 N 0 0 I N N2 N₃ The ratio of N, to N2 when N, is maximum is (a) at no time this is possible (b) 2 (c) 1/2 | 12 |

116 | 30. A newly prepared radioactive nuclide has a decay constant 2 of 10-s-. What is the approximate half-life of the nuclide? (a) 1 hour (b) 1 day (c) 1 week (d) 1 month 1: . | 12 |

117 | 1 ( g ) of hydrogen is converted into ( 0.993 g ) of helium in a thermonuclear reaction. Then energy released is ( mathbf{A} cdot 63 times 10^{7} J ) В. ( 63 times 10^{10} mathrm{J} ) ( mathbf{D} cdot 63 times 10^{20} J ) | 12 |

118 | When four hydrogen nuclei combine to form a helium nucleus in the interior of sun, the loss in mass in 0.0625 amu. How much energy is released? | 12 |

119 | The half life of a radioactive nucleus is 50 days.The time interval ( left(t_{2}-t_{1}right) ) between the time ( t_{2} ) when ( frac{2}{3} ) of it has decayed and the time ( t_{1} ) when ( frac{1}{3} ) of it had delayed is- A. 50 days B. 60 days c. 15 days D. 30 days | 12 |

120 | Two nucleons are at a separation of one Fermi. Protons have a charge of ( +1.6 times ) ( 10^{-19} ) C. The net nuclear force between them is ( F_{1}, ) if both are neutrons, ( F_{2} ) if both are protons and ( F_{3} ) if one is proton and the other is neutron. Then. A ( . F_{1}=F_{2}>F_{3} ) в. ( F_{1}=F_{2}=F_{3} ) c. ( F_{1}<F_{2}F_{2}>F_{3} ) | 12 |

121 | A radioactive element ( boldsymbol{A} ) on disintegration gives two elements ( B ) and ( C . ) If ( B ) is helium and ( C ) is the element of atomic number 90 and atomic mass 234 , the element ( A ) is: ( A cdot frac{238}{92} U ) B ( cdot_{88}^{24} R a ) ( mathbf{c} cdot_{90}^{24} T h ) D・ ( 23372 a ) | 12 |

122 | In the nuclear fusion reaction ( :_{1}^{2} boldsymbol{H}+_{1}^{3} ) ( boldsymbol{H} rightarrow_{2}^{4} boldsymbol{H} e+boldsymbol{n}, ) given that the repulsive potential energy between the two nuclei is ( sim 7.7 times 10^{-14} mathrm{J} ), the temperature to which the gases must be heated to initiate the reaction is nearly (Boltzmann’s constant ( left.k=1.38 times 10^{-23} mathrm{J}right) ) ( mathbf{A} cdot 10^{7} K ) B . ( 10^{5} K ) ( mathbf{c} cdot 10^{3} K ) D. ( 10^{9} K ) | 12 |

123 | For a radioactive substance, show the variation of the total mass disintegrated as a function of time ( t ) graphically. | 12 |

124 | ( ^{238} U ) decays with a half-life of ( 4.5 times 10^{9} ) years, the decay series eventually ending at ( ^{206} P b, ) which is stable. A rock sample analysis shows that the ratio of the number of atoms of ( ^{206} P b ) to ( ^{238} U ) is ( 0.0058 . ) Assuming that all the ( ^{206} P b ) is produced by the decay of ( ^{238} U ) and that all other half-lives on the chain are negligible, the age of the rock sample is ( left(ln 1.0058=5.78 times 10^{-3}right) ) A . ( 38 times 10^{8} ) years B. ( 38 times 10^{6} ) years C ( .19 times 10^{8} )years D. ( 19 times 10^{6} ) years | 12 |

125 | What is the ( Q- ) value of the reaction? ( boldsymbol{P}+^{7} boldsymbol{L i} rightarrow^{4} boldsymbol{H} boldsymbol{e}+^{4} boldsymbol{H} boldsymbol{e} ) The atomic masses of ( ^{1} boldsymbol{H},^{4} boldsymbol{H} boldsymbol{e} ) and ( ^{7} boldsymbol{L} boldsymbol{i} ) are ( 1.007825 u, 4.0026034 u ) and ( 7.016004 u ) respectively A . 17.35 MeV в. ( 18.06 mathrm{MeV} ) c. 177.35 МеV D. 170.35 MeV | 12 |

126 | How many ( ^{137} ) Cs need to be present in each ( k g ) of body tissue if an equivalent does for one week is 3.55 Sv? A ( cdot 1.25 times 10^{-9} ) B . ( 1.25 times 10^{11} ) C. ( 1.25 times 10^{13} ) D. none | 12 |

127 | The man-made element which was made in the nuclear reactor is A. polonium B. plutonium c. thorium D. uranium | 12 |

128 | Which of the following is an isotope of hydrogen? A. Deuterium B. Trinium c. Promium D. All of the above | 12 |

129 | The only, most stable nucleus formed by bombarding either ( _{13}^{27} A l ) by neutrons or ( _{11}^{23} N a ) by deutrons is: B . ( frac{30}{14} ) Si ( mathbf{c} cdot_{12}^{24} M g ) | 12 |

130 | Consider the nuclear reaction ( boldsymbol{X}^{200} rightarrow boldsymbol{A}^{110}+boldsymbol{B}^{90}+ )energy If the binding energy per nucleon for ( X, A ) and ( B ) is ( 7.4 M e V, 8.2 M e V ) and ( 8.2 M e V ) respectively. What is the energy released? A ( .200 mathrm{MeV} ) В. ( 160 mathrm{MeV} ) c. ( 110 M e V ) D. 90 MeV | 12 |

131 | Masses of two isobars ( _{29} C u^{64} ) and ( 30 Z n^{64} ) are ( 63.9298 u ) and ( 63.9292 u ) respectively. It can be conclude from these data that A. Both the isobars are stable B . ( Z n^{64} ) is radioactive, decaying to ( C u^{64} ) through ( beta- ) decay C. ( C u^{64} ) is radioactive, decaying to ( Z n^{64} ) through ( gamma ) decay D. ( C u^{64} ) is radioactive, decaying to ( Z n^{64} ) through ( beta- ) decay | 12 |

132 | Two protons attract each other when the distance between them is A ( cdot 10^{-18} mathrm{m} ) m ( mathrm{r}^{-18} mathrm{m}^{-} ) B. ( 10^{-20} mathrm{m} ) ( mathbf{c} cdot 10^{-15} mathrm{m} ) D. ( 10^{-22} mathrm{m} ) | 12 |

133 | The electron emitted in beta radiation originates from A. inner orbits of atoms B. free electrons existing in nucle c. decay of a neutron in a nucleus D. photon escaping from the nucleus | 12 |

134 | The kinetic energy of an ( alpha- ) particle which flies out of the nucleus of a ( R a^{226} ) atom in radioactive disintegration is 4.78 ( M ) ev. Find the total energy evolved during the escape of the ( alpha- ) particle. | 12 |

135 | The energy supplied to Kolkata by the state electricity board during an average November week day was 40 GWh. If this energy could be obtained by the conservation of matter, how much mass would have to be annihilated? A ( .1 .6 g ) B. ( 2.2 mathrm{g} ) c. ( 4.0 mathrm{g} ) D. ( 1.6 mathrm{kg} ) | 12 |

136 | The two elements, with same number of electrons but different mass number, are known as A. isotopes B. isomers c. isotones D. isobars | 12 |

137 | If ( 2 g ) of hydrogen is converted into 1.986gm Helium in a thermonuclear reaction, the energy released is ( A cdot 63 times 10^{7} J ) B. ( 63 times 10^{10} J ) c. ( 126 times 10^{10} J ) D. ( 6.3 times 10^{20} J ) | 12 |

138 | The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths, ( lambda_{1} / lambda_{2} ) of the photons emitted in this process is: A ( cdot frac{9}{7} ) B. ( frac{7}{5} ) c. ( frac{27}{5} ) D. ( frac{20}{7} ) | 12 |

139 | What is the relation between ( _{8} X^{16} ) and ( mathbf{8} boldsymbol{X}^{mathbf{1 7}} mathbf{?} ) A. Isotopes B. Isobars c. Isotones D. Isoelectronics | 12 |

140 | Consider the following statements ( (X ) and ( Y ) stand for two different elements) (I) ( _{32} X^{65} ) and ( _{33} Y^{65} ) are isotopes. (II) ( _{42} X^{86} ) and ( _{42} Y^{85} ) are isotopes. (III) ( 85^{174} ) and ( _{88} Y^{177} ) have the same number of neutrons. ( (mid V)_{92} X^{235} ) and ( _{94} Y^{235} ) are isobars The correct statements are A. Il and IV only B. I, II and IV only c. ॥, III and IV only D. I, II, III and IV | 12 |

141 | Which one of the following is a correct statement about the atom bomb? A. a chemical reaction producing a large amount of heat B. a nuclear explosion caused by a controlled chain reaction c. a nuclear explosion caused by fusion of two hydrogen nuclei D. a nuclear explosion caused by an uncontrolled chain reaction | 12 |

142 | An ( alpha- ) particle of energy 5 MeV is scattered through ( 180^{circ} ) by a fixed uranium nucleus. The distance of closest approach is of the order of A ( cdot 10^{-12} mathrm{cm} ) B . ( 10^{-10} mathrm{cm} ) ( c cdot 1 A ) D. ( 10^{-15} mathrm{cm} ) | 12 |

143 | Calculate the energy released in MeV during the reaction ( _{3}^{7} L i+_{1}^{1} H rightarrow ) ( 2left[begin{array}{l}4 \ 2end{array} boldsymbol{H} eright] ) if the masses of ( _{3}^{7} L i_{11}^{1} boldsymbol{H} ) and ( _{2}^{4} H e ) are 7.018,1.008 and ( 4.004 a m u ) respectively. | 12 |

144 | If four atoms of hydrogen combine to form an ( 2^{4} H e ) atom, then the amount of energy released is : A. ( 26.7 mathrm{MeV} ) в. ( 25.3 mathrm{MeV} ) ( mathrm{c} .22 mathrm{MeV} ) D. ( 24.5 mathrm{MeV} ) | 12 |

145 | Though three fundamental particles are present in almost all elements. One element does not have : A. neutron B. proton c. electron D. nucleons | 12 |

146 | Which of the following assertions are correct? This question has multiple correct options A. A neutron can decay to a proton only inside a nucleus B. A proton can change to a neutron only inside nucleus C. An isolated neutron can change into a proton D. An isolated proton can change int a neutron | 12 |

147 | Fast neutrons can easily be slowed down by A. the use of lead shielding B. passing them through water c. elastic collision with heavy nuclei D. applying a strong electric field | 12 |

148 | What is the role of a moderator in a nuclear reactor? | 12 |

149 | For a nuclear reactor to run in crtitcal condition the reproduction factor should be ( A cdot=1 ) B ( .>1 ) ( c cdot>>1 | 12 |

150 | What is the main difference between isotopes of the same element? | 12 |

151 | State the law of radioactive decay Hence derive the expression ( N= ) ( N_{0} e^{-lambda t} ) where symbols have their usual meanings. | 12 |

152 | During ( beta- ) decay (beta minus), the emission of antineutrino particle is supported by which of the following statement(s)? This question has multiple correct options A. Angular momentum conservation holds good in any nuclear reaction B. Linear momentum conservation holds good in any nuclear reaction C. The KE of emitted ( beta- )particle is varying continuously to a maximum value D. None of the above | 12 |

153 | The particle emitted in the nuclear reaction ( z^{A}=_{z+1} mathbf{Y}^{A}+ldots . . ) will be A . ( alpha ) -particle B . ( beta^{-} ) -particl c. ( beta+ ) -particle D. Photon | 12 |

154 | Assertion ( mathbf{9 2} mathbf{U}^{mathbf{2 3 5}}+mathbf{o} mathbf{n}^{mathbf{1}} longrightarrow mathbf{5 6} mathbf{B a}^{mathbf{1 4 0}}+mathbf{3 6} mathbf{K e}^{mathbf{9 3}}+ ) ( 3 mathrm{on}^{1} ) is a nuclear fission reaction. Reason Neutrons emitted do not react further. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

155 | Half-life of a radioactive substance A is two times the half-life of another radioactive substance B. Initially, the number of ( A ) and ( B ) are ( N_{A} ) and ( N_{B} ) respectively. After three half-lives of ( A ) number of nuclei of both are equal Then, the ratio ( N_{A} / N_{B} ) is A . ( 1 / 4 ) в. ( 1 / 8 ) c. ( 1 / 3 ) D. ( 1 / 6 ) | 12 |

156 | Radioactive material’A’ has decay constant ( ^{prime} 8 lambda^{prime} ) and material ‘B’ has decay constant ( ^{prime} lambda^{prime} . ) Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material ‘B’ to that of ‘A’ will be ( frac{1}{e} ? ) A ( cdot frac{1}{lambda} ) в. ( frac{1}{7 lambda} ) c. ( frac{1}{8 lambda} ) D. ( frac{1}{9 lambda} ) | 12 |

157 | A sample of a radioactive substance has a half-life of 20 minutes. If the sample’s activity is 200 counts/second. Find out the number of counts/second after one hour passes? A . 6.25 counts/sec B. 12.5 counts/sec C. 25 counts/sec D. 50 counts/sec E. 100 counts/sec | 12 |

158 | Assertion The last element in a group is radioactive Reason In case of elements with high atomic masses, nucleus is unstable. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

159 | An ( alpha ) -particle captures two electrons. What does it change to? A. Hydrogen atom B. Helium atom c. Lithium atom D. Berrylium atom | 12 |

160 | Atomic reactor is based on A. controlled chain reaction B. uncontrolled chain reaction c. nuclear fission D. nuclear fusion | 12 |

161 | A 280 -day-old radioactive substance shows an activity of 6000 dps. 140 days later its activity becomes 3000 dps. What was its initial activity? A. 20000 dps в. 24000 dps c. 120000 dps D. ( 6000 d ) p | 12 |

162 | Hydrogen bomb is based on the principle of A. uncontrolled fusion reaction B. controlled fusion reaction c. uncontrolled fission reaction D. controlled fission reaction | 12 |

163 | Which of the following are used as Control Rods: a) Boron rods b) Cadmium rods c) Copper rods A . a is correct B. b is correct c. c is correct D. a,b are correct | 12 |

164 | what is the physical significance of negative energy of electron in atom? | 12 |

165 | A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The halflife of the source is? A. 80 min B. 120 min c. 20 min D. 30min | 12 |

166 | What particle was emitted? A . Alpha B. Beta ( c . ) Gamma D. None of the above | 12 |

167 | Which differential equation correctly represents the above process? A ( cdot frac{d N}{d t}+lambda N=q_{0} t ) в. ( frac{d N}{d t}-lambda N=q_{0} t ) c. ( frac{d N}{d t}+q_{0} t=lambda N ) D. ( frac{d N}{d t}+q_{0} t=-lambda N ) | 12 |

168 | are used to absorb the neutrons in a nuclear reactor. | 12 |

169 | Identify the element if it has mass number 14 and 8 neutrons. A. Isotope of oxygen B. Isobar of oxygen c. Isotope of carbon D. Isobar of carbon | 12 |

170 | Which scientist proposed the concept of atomic mass? A. Avogadro B. Gay Lussac c. Prout D. Dalton | 12 |

171 | The species ( N e, N a^{+} ) and ( F^{-} ) have the same: A. number of protons B. number of nucleons c. number of electrons D. mass number | 12 |

172 | The half-life of the source is 30 min. What correct readings would you expect to obtain, with no absorber present, one hour after original readings were taken? | 12 |

173 | All conventional modern thermonuclear warheads are also called as A. fission-fusion-fission B. Neutron bombs c. cobalt bombs D. three stage bomb | 12 |

174 | Water used as moderator in nuclear reactor is called: A. heavy water B. hard water c. nuclear water D. critical water | 12 |

175 | The radioactive material A and B have decay constant ( 5 lambda ) and ( lambda ) respectively.Initially both A and B have the same number of nuclei.The ratio of the number of nuclei of ( A ) and ( B ) will be ( frac{1}{e}, ) after the time is ( frac{x}{8 lambda} ) then ( x ) is | 12 |

176 | Which of the following property of an element never changes? A. Valency B. Atomic weight c. Equivalent Mass D. All the above | 12 |

177 | A radioactive nucleus of mass ( M ) emits a photon of frequency ( v ) and the nucleus recoils. The recoil energy will be A . ( h v ) B. ( M c^{2}-h v ) c. ( frac{h^{2} v^{2}}{2 M c^{2}} ) D. zero | 12 |

178 | In the radioactive transformation [ underset{Z}{A} boldsymbol{X} rightarrow_{Z+1}^{A} boldsymbol{X}_{1} rightarrow_{Z-1}^{A-4} boldsymbol{X}_{2} rightarrow_{Z}^{A-4} boldsymbol{X}_{3} ] Which are the successively emitted radiactive radiation? ( mathbf{A} cdot beta^{-}, alpha, beta^{-} ) B. ( beta^{-}, beta^{-}, alpha ) c. ( alpha, beta^{-}, beta^{-} ) D. ( alpha, alpha, beta^{-} ) | 12 |

179 | Show that ( _{92}^{230} U ) does not decay be emitting a neutron or proton. Given: ( Mleft(_{92}^{230} Uright)=230.033927 a m u ) ( Mleft(_{92}^{230} Uright)=229.033496 a m u ) ( Mleft(_{92}^{229} P aright)=229.032089 a m u ) ( boldsymbol{m}(boldsymbol{n})=mathbf{1 . 0 0 8 6 6 5 a m u} ) ( boldsymbol{m}(boldsymbol{p})=mathbf{1 . 0 0 7 8 2 5 a m u} ) | 12 |

180 | A ( 0.2 m l ) sample of a solution containing ( 1 times 10^{-7} ) curie of tritium ( _{1} H^{3} ) is injected into the blood stream of a laboratory animal. After allowing sufficient time for circulation ( 0.1 m l ) of the blood is found to have an activity of 20 disintegration per minute. What is the blood volume of the animal? A. 1.1 litre B . 0.55 litre c. 0.65 litre D. 1.65 litre | 12 |

181 | Write the complete nuclear reactions: (a) ( _{4}^{9} B e+_{2}^{4} H e longrightarrow_{6}^{12} C+ ) ( (b)_{1}^{3} H longrightarrow_{2}^{3} H e+_{-} ) ( (c) frac{14}{7} N+_{2}^{4} H e longrightarrow_{8}^{17} O+ ) (d) ( _{92}^{235} U+_{0}^{1} n longrightarrow_{38}^{92} S r+X e+3_{0}^{1} n ) ( (mathrm{e})_{3}^{7} L i+_{0}^{1} n longrightarrow 2_{2}^{4} H e+ ) ( (f)_{92}^{238} U+_{-perp-}—-longrightarrow_{92}^{239} U longrightarrow_{93}^{239} ) ( N p+ ) ( (g)_{7}^{14} N+_{0}^{1} n longrightarrow_{-}-ldots—+_{1}^{3} H ) (h) ( _{3}^{7} L i+_{-} ) ( longrightarrow_{4}^{8} B e+gamma ) radiations (i) ( _{1}^{2} boldsymbol{H}+_{text {一一一一一一一 }}_{2}^{4} boldsymbol{H} e+_{0}^{1} boldsymbol{n} ) ( (j)_{13}^{27} A l+_{0}^{1} n longrightarrow_{11}^{24} N a+ ) ( (mathrm{k})_{13}^{27} A l+_{2}^{4} H e longrightarrow_{-}——+_{1}^{1} H ) (I) ( frac{235}{92} boldsymbol{U}+_{0}^{1} boldsymbol{n} longrightarrow ) ( +_{52}^{137} boldsymbol{T} boldsymbol{e}+_{40}^{97} boldsymbol{Z} boldsymbol{r} ) ( (mathrm{m})_{34}^{86} mathrm{Se} longrightarrow_{-1}-mathrm{-}_{-1} mathrm{e} ) | 12 |

182 | are examples of isobars. ( mathbf{A} cdot_{14} S i^{31},_{15} P^{32} ) ( mathbf{B} cdot_{6} C^{13},_{7} N^{13} ) ( mathbf{C} cdot_{7} N^{14},_{7} N^{15} ) D. None of the above | 12 |

183 | Source of solar energy is due to natural fusion in which hydrogen gets converted into helium with carbon serving as a natural catalyst. This carbon cycle was proposed by A. Bothe B. Yukawa c. Ferm D. soddy | 12 |

184 | Molecular mass of dry air is A. less than moist air B. greater than moist air C . equal to moist air D. may be greater or less than moist air | 12 |

185 | Some statements about heavy water are given below: (i) Heavy water is used as a moderator in nuclear reactors. (ii) Heavy water is more associated than ordinary water. (iii) Heavy water is a more effective solvent than ordinary water. Which of the above statements are | 12 |

186 | The source of stellar energy is A. Nuclear fission B. Nuclear fusion C. Nuclear fission & fusion D. Nuclear decay | 12 |

187 | The one has maximum radioactive activity A. Uranium B. Plutonium c. Radium D. Thorium | 12 |

188 | If the mass of proton ( =1.008 a . m . u ) and mass of neutron ( =1.009 a . m . u ) then binding energy per nucleon for ( _{4} B e^{9}(text { mass }=9.012 a m u) ) would be: A . 40.065 Mev B. ( 60.44 mathrm{MeV} ) c. 67.2 Mev D. 6.72 Mev | 12 |

189 | The ionising power of ( alpha ) -particles is roughly times that of ( boldsymbol{beta} ) particle. Fill in the blank. A ( cdot 10^{4} ) B . 10 c. 10 D. 1/16 | 12 |

190 | Which process is responsible in Hydrogen bomb? If ( 20 mathrm{N} ) force is applied on a wall which doesn’t move the wall than work done by wall is. | 12 |

191 | The nuclear fusion reaction between deuterium and tritium takes place A. at ordinary temperature and pressure B. at low temperature and low pressure C . at very high temperature and very high pressure D. when the temperature is near absolute zero | 12 |

192 | A ( 1 ~ M e V ) positron encounters a 1 Me ( V ) electron travelling in opposite direction The total energy released is (in MeV) A .2 в. 3.02 c. 1.02 D. 2.04 | 12 |

193 | Chernobyl tragedy occurred in A. 26th May, 1966 B. 26th April, 1986 c. 6th August, 1947 D. 9th May, 1945 | 12 |

194 | X-ray beam can be deflected: A. by an electric field B. by a magnetic field C . by electric &magnetic fields both D. neither by an electric field nor by a magnetic field | 12 |

195 | 34. Two radioactive materials X, and X, have decay constanta 102 and 2, respectively. If initially they have the same number of nuclei, the ratio of the number of nuclei of X to that of X, will be lle after a time (a) 102 112 102 | 12 |

196 | Match the following reactions: ( (boldsymbol{A})_{4} boldsymbol{B} boldsymbol{e}^{9}+_{2} boldsymbol{H} boldsymbol{e}^{4} rightarrow_{boldsymbol{6}} boldsymbol{C}^{12}+cdots ) ( (i)_{2} H e^{4} ) ( (B)_{6} C^{12}+cdots rightarrow_{5} B^{10}+_{2} H e^{4} ) ( (i i)_{0} n^{1} ) ( (C)_{7} N^{14}+cdots rightarrow_{8} O^{17}+_{1} H^{1} ) ( (i i i i)_{1} D^{2} ) ( (D)_{20} C a^{40}+cdots rightarrow_{19} K^{37}+_{2} H e^{4} ) ( (i v)_{1} H^{1} ) ( mathbf{A} cdot A-i, B-i i, C-i i i, D-i v ) ( mathbf{B} cdot A-i i, B-i i i, C-i, D-i v ) ( mathbf{c} cdot A-i v, B-i i, C-i i i, D-i ) ( mathbf{D} cdot A-i i i, B-i i, C-i, D-i v ) | 12 |

197 | Two radioactive sources ( A ) and ( B ) initially contain equal number of radioactive atoms. Source A has a half- life of 1 hour and source ( mathrm{B} ) has a half-life of 2 hours. At the end of 2 hours, the ratio of the rate of disintegration of ( A ) to that of B is : A . 1: 2 B. 2: ( c cdot 1: 1 ) D. 1: | 12 |

198 | The age of the wood if only ( frac{1}{16} t h ) part of original ( C^{14} ) is present in its piece is ( T ) of ( C^{14} ) is 5,580 years A. 5580 years B. 11,160 years c. 22320 years D. 16740 years | 12 |

199 | The fraction of a radioactive material which remains active after time ( t ) is ( mathbf{9} / mathbf{1 6} . ) The fraction which remains active after time ( t / 2 ) will be A. ( frac{4}{5} ) в. ( frac{7}{8} ) c. ( frac{3}{5} ) D. | 12 |

200 | ( frac{sqrt{2}}{2} ) | 12 |

201 | Find ( x ) in the following nuclear reaction ( _{12} M g^{24}+_{2} H e^{4} rightarrow_{14} S i^{x}+_{0} n^{1} ) A . 17 B. 27 c. 37 D. 24 | 12 |

202 | If the half lives of a radioactive element for ( alpha ) and ( beta ) decay are 4 years and 12 years respectively, then the percentage of the element that remains after 12 years will be A . ( 6.25 % ) B . ( 12.5 % ) c. ( 25 % ) D. 50 % | 12 |

203 | ( P ) and ( Q ) are two elements which form ( P_{2} Q_{3} ) and ( P Q_{2} . ) If 0.15 mole of ( P_{2} Q_{3} ) weight ( 15.9 mathrm{g} ) and 0.15 mole of ( P Q_{2} ) weight 9.3 g. what are atomic weights of ( P ) and ( Q ? ) ( A cdot 18 ) and 26 B. 26 and 26 c. 26 and 18 D. 18 and 18 | 12 |

204 | Assertion ( mathbf{3} boldsymbol{H} ) isotopes does not undergo fusion of the type ( _{1}^{3} H+_{1}^{2} H rightarrow ) as it is rarely found in nature. Reason ( mathbf{3} boldsymbol{H} ) has half life of ( approx mathbf{1 2} boldsymbol{y} boldsymbol{e} boldsymbol{a} boldsymbol{r} boldsymbol{s} ) A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

205 | The radioactivity of a sample is ( boldsymbol{R}_{1} ) at a time ( T_{1} ) and ( R_{2} ) at a time ( T_{2} . ) If the half- life of the specimen is ( T, ) the number of atoms that have disintegrated in the ( operatorname{time}left(T_{2}-T_{1}right) ) is proportional to: A ( . R_{1} T_{1}-R_{2} T_{2} ) B ( . R_{1}-R_{2} ) c. ( frac{left(R_{1}-R_{2}right)}{T} ) D. ( left(R_{1}-R_{2}right) T ) | 12 |

206 | Two samples ( A ) and ( B ) of same radioactive nuclide are prepared Sample A has twice the initial activity of sample B. For this situation, mark out the correct statement(s): This question has multiple correct options A. The half-lives of both the samples would be same B. The half-lives of the samples are different C. After each has passed through 5 half-lives, the ratio of activity of A to B is 2: D. After each has passed through 5 half-lives, ratio of activities of A to B is 64: | 12 |

207 | 62. A sample of radioactive material decays simultaneously by two processes A and B with half-lives respectively. For the first half hour it decays with the process A, next one hour with the process B, and for further half an hour with both A and B. If, originally, there were N. nuclei, find the number of nuclei after 2 h of such decay. (a) No (b) No – 0 (2) 8 (c) N m (2) 4 (d) No () (2) element X decays first hy nositron emission and then | 12 |

208 | When four hydrogen nuclei fuse together to form a helium nucleus, then in this process A. energy is absorbed B. energy is liberated c. absorption and liberation of energy depends upon the temperature. D. energy is neither liberated nor absorbed | 12 |

209 | If the energy of an electron in Hydrogen atom is given by expression, ( -1312 / n^{2} k J m o l^{-1}, ) then the energy required to excite the electron from ground state to second orbit is A ( cdot 328 k J m o l^{-1} ) B. ( 656 k J ) mol ( ^{-1} ) ( mathbf{c} cdot 984 k J m o l^{-1} ) D. ( 1312 k J m o l^{-1} ) | 12 |

210 | The percentage of mass lost during nuclear fusion is A . 0.1% B. 0.4% c. 0.5% D . 0.65% | 12 |

211 | Express ( 16 mathrm{mg} ) mass into equivalent energy in electron volt. | 12 |

212 | One of the methods of producing He is to bombard ( L i ) with the following projectile A . ( alpha ) -particles B. electrons c. protons D. neutrons | 12 |

213 | Which of the following process represents ( gamma ) -decay? A ( cdot frac{A}{Z} X+_{0}^{1} n rightarrow_{Z-2}^{A-3} X+c ) B . ( _{Z} X+_{-1} e rightarrow_{Z-1}^{A} X+g ) c. ( frac{A}{Z} X+r rightarrow_{Z-1}^{A} X+a+b ) D. ( frac{A}{Z} X rightarrow frac{A}{Z} X+gamma ) | 12 |

214 | f a proton and anti-proton come close to each other and annihilate, how much energy will be released? A . ( 1.5 times 10^{-10} mathrm{J} ) B . ( 3 times 10^{-10} J ) c. ( 4.5 times 10^{-10} J ) D. ( 2 times 10^{-10} mathrm{J} ) | 12 |

215 | Why are the energies different? Mass of ( _{20}^{42} C a=40.962278 u, ) mass of proton ( =1.007825 u ) | 12 |

216 | In a hydrogen atom, the binding energy of the electron in the nth state is ( boldsymbol{E}_{boldsymbol{n}} ) , then the frequency of revolution of the electron in the nth orbit is: A ( cdot 2 E_{n} / n h ) в. ( 2 E_{n} n / h ) c. ( E_{n} / n h ) D. ( E_{n} n / h ) | 12 |

217 | Identify the similarity between isotopes of the same element. A. They have the same particles in the nucleus B. They have the same number of neutrons C. They are equally abundant in nature D. They have the same number of protons E. They have the same mass. | 12 |

218 | Assertion It is not possible to use ( ^{35} C l ) as the fuel for fusion energy. Reason The binding energy of ( 35 C l ) is too small. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

219 | X-rays are incident on a target metal atom having 30neutrons. The ratio of radii of nucleus to that of Helium nucleus is ( 14^{1 / 3} ) (a) Find the atomic number of target atom. (b) Find the frequency of ( boldsymbol{K}_{boldsymbol{alpha}} ) line emitted by this metal. ( boldsymbol{R}=mathbf{1 . 1} times mathbf{1 0}^{mathbf{7}} mathbf{m}^{-1}, boldsymbol{c}=mathbf{3} times mathbf{1 0}^{mathbf{8}} mathbf{m} / mathbf{s} ) A ( .20,1.546 times 10^{4} mathrm{Hz} ) В . 24. ( 1.546 times 10^{1} 0 H z ) ( mathbf{c} cdot 26,1.546 times 10^{1} 8 H z ) D. None of these | 12 |

220 | What describe the Einsteins equation for the relativity of mass and energy? A. a small amount of mass contains a lot of energy. B. a small amount of energy can be converted into a large amount of mass. C. a small amount of mass contains a small amount of energy. D. mass can be converted into energy, but energy cannot be converted mass. E. energy can be converted into mass, but mass cannot be converted into energy. | 12 |

221 | There is a stream of neutrons with a kinetic energy of ( 0.0327 e V ). If the halflife of neutron is ( 700 s, ) if ( frac{x}{1000} ) fraction of neutrons will decay before they travel a distance 3 of ( 10 k m . ) Find ( x ) | 12 |

222 | Natural chlorine contains chlorine in the form of the isotope ( ^{35} C l(75.5 %) ) and ( ^37 C l(24.5 %) . ) Calculate the average atomic mass of natural chlorine. A . 35.49 B. 35 ( c .37 ) D. 36 | 12 |

223 | Which process is responsible in Hydrogen bomb? | 12 |

224 | Two deuterium nuclei each of mass ‘ ( boldsymbol{m}^{prime} ) fuse together to form a Helium nucleus, releasing an energy ( boldsymbol{E} ). If ( ^{prime} boldsymbol{c}^{prime} ) is the velocity of light, the mass of Helium nucleus formed will be: A ( cdot 2 m+frac{E}{c^{2}} ) в. ( frac{E}{m c^{2}} ) c. ( _{m+frac{E}{c^{2}}} ) D. ( 2 m-frac{E}{c^{2}} ) | 12 |

225 | 57 Co will emit 27 radiation ( mathbf{A} cdot beta^{-} ) в. ( beta^{+} ) ( c cdot alpha ) D. electron capture | 12 |

226 | Img of matter convert into energy will give A. 90 joul B. ( 9 times 10^{3} ) joule c. ( 9 times 10^{5} ) joule D. ( 9 times 10^{10} ) joule | 12 |

227 | Hydrogen bomb is based on the principle of: A. nuclear fission B. natural radioactivity c. nuclear fusion D. artificial radioactivity | 12 |

228 | A hydrogen bomb is a ( A . ) A hydrogen bomb is a B. uncontrolled nuclear fision c. uncontrolled nuclear fusion D. controlled nuclear fusion | 12 |

229 | If ( mathbf{M}(mathbf{A}, mathbf{Z}), boldsymbol{M}_{boldsymbol{p}}, boldsymbol{a} boldsymbol{n} boldsymbol{d}, boldsymbol{M}_{boldsymbol{n}} ) denote the masses of the nucleus respectively in units of ( left(1 u=931.5 M e V / C^{2}right) ) and BE represents its bonding energy in MeV, then – A ( . M(A, Z)=Z M_{p}+(A-Z) M_{n}-B E ) B. ( M(A, Z)=Z M_{p}+(A-Z) M_{n}+B E / C^{2} ) C ( . M(A, Z)=Z M_{p}+(A-Z) M_{n}-B E / C^{2} ) D. ( M(A, Z)=Z M_{p}+(A-Z) M_{n}+B E ) | 12 |

230 | Could this reaction occur? Proton ( rightarrow ) neutron ( + ) other particles A. Yes, if the other particles have much more kinetic energy than mass energy. B. Yes, but only if the proton has potential energy (due to interactions with other particles) C. No, because a neutron is more massive than a proton. D. No, because a proton is positively charged while a neutron is electrically neutral. | 12 |

231 | In a fission process, nucleus A divides into two nuclei B and C, their binding energies being ( mathbf{E}_{mathbf{a}^{*}} quad boldsymbol{E}_{boldsymbol{b}} ) and ( boldsymbol{E}_{boldsymbol{c}} ) respectively. Ihen A ( cdot mathbf{E}_{mathrm{b}}+mathrm{E}_{mathrm{c}}=mathrm{E}_{mathrm{a}} ) в. ( mathrm{E}_{mathrm{b}}+mathrm{E}_{mathrm{c}}>mathrm{E}_{mathrm{a}} ) c. ( mathrm{E}_{mathrm{b}}+mathrm{E}_{mathrm{e}}<mathrm{E}_{mathrm{a}} ) D. ( mathrm{E}_{mathrm{b}} mathrm{E}_{mathrm{c}}=mathrm{E}_{mathrm{a}} ) | 12 |

232 | Fill up the blanks. When ( _{6} C^{14} ) isotope undergoes ( beta ) -decay the resulting new element is | 12 |

233 | With the help of one example, explain how the neutron to proton ratio changes during alpha decay of a nucleus. | 12 |

234 | State any two differences between chemical reactions and nuclear reactions. | 12 |

235 | Which atom contains exactly 15 neutrons? A ( cdot P^{32} ) (atomic number ( =17 ) ) B. ( S^{32} ) (atomic number ( =16 ) ) ( mathrm{c} cdot O^{15} ) (atomic number ( =8 ) D. ( N^{15} ) stomic number ( =7 ) | 12 |

236 | In a series of radioactive decays, if a nucleus of mass number 180 and atomic number 72 decays into another nucleus of mass number 172 and atomic number 69 , then the number of ( alpha ) and ( beta ) particles released respectively are A .2,3 в. 2,2 c. 2,1 D. 2,0 E . 1,3 | 12 |

237 | The equivalent weights of a metal are 18.66 and ( 28, ) then atomic weight of metal may be? ( mathbf{A} cdot 18.66 ) B. 28 c. 56 D. 25 | 12 |

238 | Reactor generates ………………………. energy. | 12 |

239 | Which of the following transformations is not correct? ( mathbf{A} cdot_{33}^{75} A s+_{2}^{4} H e longrightarrow_{35}^{78} B r+_{0}^{1} n ) B . ( _{3}^{7} L i+_{1}^{1} H longrightarrow_{4}^{7} B e+_{0}^{1} n ) C. ( 45 mathrm{Sc}+_{0}^{1} n longrightarrow_{20}^{45} mathrm{Ca}+_{0}^{1} n ) ( n ) D. ( _{83}^{099} mathrm{Bi}+_{1}^{2} mathrm{H} longrightarrow_{84}^{210} mathrm{Po}+_{0}^{1} n ) | 12 |

240 | In one average-life, A. half the active nuclei decay B. less than half the active nuclei decay. C. more than half the active nuclei decay. D. all the nuclei decay. | 12 |

241 | One atomic mass unit is equal to: A ( cdot 1.66 times 10^{-27} g ) B . ( 1.66 times 10^{-24} g ) c. ( 1.66 times 10^{-23} g ) D. ( 1.66 times 10^{-25} g ) | 12 |

242 | What is the name given to the atoms whose nuclei contain the same number of proton but different number of neutrons? | 12 |

243 | State radioactive decay law. Derive ( N=N_{o} e^{-lambda t} ) for a radioactive element. | 12 |

244 | 22. The energy spectrum of B particles [number N(E) as a function of Benergy E] emitted from a radioactive source is (b) 1 N(E) N(E) (d) N(E) N (E) E (AIEEE 2006) | 12 |

245 | The term that would apply to ( ^{16} mathrm{O} ) and ( 170 ? ) A. Isotopes B. Isobars c. Isoelectronics D. Isotones | 12 |

246 | The device in which the nuclear fission and release of energy is controlled, is known as: A. thermopile B. thermostat c. nuclear reactor D. cloud chamber | 12 |

247 | Match the nuclear processes given in column I with the appropriate option(s) in column II. | 12 |

248 | 77. Consider the reaction, H+H – He+ on m(H) = 2.014082 u, m(He) = 3.016029 u, m(on)=1.008665 u Then, mark the correct option. (a) Threshold energy of 3.23 MeV is required to initiate the reaction (b) Reaction occurs when total KE of reactants exceeds 3.23 MeV (c) Reaction occurs such that final total KE is 3.23 MeV lesser than total initial KE (d) No, threshold energy is required for the reaction | 12 |

249 | What is (a) mass defect, and (b) binding energy in Oxygen ( _{8}^{16} O, ) whose nuclear mass is 15.995 amu. ( left(m_{p}=right. ) ( mathbf{1 . 0 0 7 8 a m u} ; boldsymbol{m}_{n}=mathbf{1 . 0 0 8 7 a m u} ) | 12 |

250 | Carbon-10 has a half-life of about 19 seconds. How many half-lives does it undergo in 2 minutes and 32 seconds? A. 8 half-lives B. 7 half-lives c. 6 half-lives D. 5 half-lives E. 4 half-lives | 12 |

251 | What is the mass of one atom of ( C-12 ) in grams? ( mathbf{A} cdot 1.992 times 10^{-23} mathrm{gm} ) B . ( 1.989 times 10^{-23} mathrm{gm} ) C ( cdot 1.892 times 10^{-23} mathrm{gm} ) D. ( 1.965 times 10^{-23} mathrm{gm} ) | 12 |

252 | The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is ( left(V text { elocity of } operatorname{light}=3 times 10^{8} m / sright) ) A ( cdot 1.5 times 10^{6} ) B . ( 2.5 times 10^{6} ) ( c cdot 3 times 10^{6} ) D. ( 7.5 times 10^{6} ) | 12 |

253 | The type of radiation absorbed by ( boldsymbol{C O}_{2} ) molecule in atmosphere is A. ( X ) -rays B. Gamma rays c. Infra-red rays D. ( U V ) – rays | 12 |

254 | From the following equations, pick out the possible nuclear fusion reaction This question has multiple correct options ( mathbf{A} cdot_{6} C^{13}+_{1} H^{1} rightarrow_{6} C^{14}+4.3 M e V ) ( mathbf{B} cdot_{6} C^{12}+_{1} H^{1} rightarrow_{7} C^{13}+2 M e V ) ( mathbf{C} cdot_{7} C^{14}+_{1} H^{1} rightarrow_{8} O^{15}+7.3 M e V ) ( mathbf{D} cdot_{92} U^{235}+_{0} n^{1} rightarrow_{54} X e^{104}+_{38} X r^{94}+_{0} n^{1}+_{0} n^{1}+y+ ) ( 200 M e V ) | 12 |

255 | Consider ( boldsymbol{alpha}- ) particles ( , boldsymbol{beta}- ) particles and ( gamma- ) rays, each having an energy of ( 0.5 mathrm{MeV} . ) In increasing order of penetrating powers, the radiations are A. ( alpha, beta, gamma ) в. ( alpha, gamma, beta ) c. ( beta, gamma, alpha ) D. ( gamma, beta, alpha ) | 12 |

256 | ( F_{p p}, F_{n n} ) and ( F_{n p} ) are the nuclear forces between proton-proton, neutron-neutron and neutron-proton respectively. Then relation between them is ( mathbf{A} cdot F_{p p}=F_{n n} neq F_{n p} ) B . ( F_{p p} neq F_{n n}=F_{n p} ) ( mathbf{c} cdot F_{p p}=F_{n n}=F_{n p} ) D ( cdot F_{p p} neq F_{n n} neq F_{n p} ) | 12 |

257 | Neutron decay in the free space is given as follows: ( mathbf{o} boldsymbol{n}^{mathbf{1}} rightarrow_{mathbf{1}} boldsymbol{H}^{mathbf{1}}+_{-mathbf{1}} boldsymbol{e}^{mathbf{0}}+[mathbf{j}] ) Then, the parenthesis represents A. photon B. graviton c. neutrino D. antineutrino | 12 |

258 | 19. If the binding energies per nucleon in Li and He nuclei are 5.60 MeV and 7.06 MeV, respectively, then in the reaction p+ Li 2 He the energy of proton must be (a) 1.46 MeV (b) 39.2 MeV (c) 28.24 MeV (d) 17.22 MeV (AIEEE 2006) | 12 |

259 | (0) 100 101 55. If the energy released in the fission of one nucleus is 200 MeV. Then the number of nuclei required per second in a power plant of 16 kW will be (a) 0.5 x 1014 (b) 0.5 x 1012 (c) 5 x 1012 (d) 5 x 1014 | 12 |

260 | For maintaining sustained chain reaction, the following is required A. protons B. electrons c. neutrons D. positrons | 12 |

261 | Assertion Thermonuclear fusion reactions may become the source of unlimited power for the mankind. Reason A single fusion event involving isotopes of hydrogen produces more energy than energy from nuclear fission of ( frac{235}{93} U ) A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

262 | State True or False: Two atoms can be isotones and isobars simultaneously. A. True B. False | 12 |

263 | One gram of a radioactive substance disintegrates at the rate of ( 3.7 times 10^{10} ) disintegrations per second. The atomic mass of the substance is ( 226 . ) Calculate its mean life: | 12 |

264 | Consider the nuclear change ( mathbf{9 3}^{237} boldsymbol{X} stackrel{-boldsymbol{alpha}}{longrightarrow} boldsymbol{A} stackrel{-boldsymbol{beta}}{longrightarrow} boldsymbol{B} stackrel{-boldsymbol{alpha}}{longrightarrow} boldsymbol{C} ) Which of the following statements is not correct? A. Mass number of B is 233 B. Atomic number of A is 9 c. ( c ) is an isotope of D. B is an isobar of A | 12 |

265 | A radioactive nuclide X decays into nuclei Y and Z by simultaneous disintegration as shown.Effective decay constant for the disintegration is ( A cdot lambda_{1}+lambda_{2} ) B. ( frac{lambda_{1} lambda_{2}}{lambda_{1}+lambda_{2}} ) ( c cdot frac{lambda_{1}+lambda_{2}}{2} ) D. ( frac{2 lambda_{1} lambda_{2}}{lambda_{1}+lambda_{2}} ) | 12 |

266 | For a radioactive element, the correct representation of number of nuclei (N) decayed after time (t) is represented by A. B. ( c ) D. | 12 |

267 | ( Omega ) 2 2 2 | 12 |

268 | The half life of a radioactive substance is 5000 years. The number of years after which its activity will decrease to 0.2 times of its initial value is: ( left(log _{10} 5=0.6990right) ) A ( cdot 1.02 times 10^{5} ) years B . ( 2.34 times 10^{6} ) years C. ( 2.06 times 10^{2} ) years D. ( 1.16 times 10^{4} ) years | 12 |

269 | In majority of radioactive elements, the ratio of the number of neutrons to that of protons A . decreases B. increases c. remains constant D. sometimes decreases sometimes increases | 12 |

270 | Calculate and compare the energy released by (a) Fusion of ( 1.0 mathrm{kg} ) of hydrogen deep within Sun (b) The fission of ( 1.0 mathrm{kg} ) of ( ^{235} mathrm{U} ) in a fission reactor | 12 |

271 | The critical mass of fissionable material is A. ( 75 mathrm{kg} ) в. ( 1 mathrm{kg} ) c. ( 20 mathrm{kg} ) D. ( 10 mathrm{kg} ) | 12 |

272 | From below which are the disadvantages of nuclear energy? A. High set up cost B. low set up cost c. waste products are useful D. None | 12 |

273 | For making atom bomb, what else is needed except ( U^{235} ? ) A. neutron B. proton C . electron D. meson | 12 |

274 | If ( Q_{1} ) and ( Q_{2} ) are the energies released in the fusion of hydrogen in Carbon nitrogen cycle and proton – proton cycle respectively, then A ( cdot Q_{1}>Q_{2} ) в. ( Q_{1}=Q_{2} ) c. ( Q_{1}<Q_{2} ) D. ( Q_{1}=2 Q_{2} ) | 12 |

275 | The following properties belong to a. The number of nucleons in the atoms of different elements remains the same b. The atomic number for different elements is different c. The number of protons and electrons is always equal A. Isotopes B. Isobars c. Isotones D. None of the above | 12 |

276 | Proportionality constant ( lambda ) is also known as – A. Decay constant B. Disintegration constant c. Radioactive constant D. All of these | 12 |

277 | Which of the following is a good nuclear fuel? A. uranium_236 B. neptunium_239 c. thorium_236 D. plutonium-239 | 12 |

278 | 23. The half-life period of a radioactive element X is the same as the mean life of another radioactive element Y. Initially they have the same number of atoms. Then (a) Y decays faster than X (b) X and Y decay equally initially (c) X and Y decay at the same rate always (d) Y will decay faster than X (AIEEE 2007) | 12 |

279 | There are ( _{text {- }-text { – }-text { – }} ) isotopes of hydrogen A. 0 B. ( c cdot 2 ) D. | 12 |

280 | Assertion Actual atomic mass is greater than mass number. Reason Mass of protons and neutrons is measured in daltons or atomic mass unit (u) but the mass of each neutron and proton is slightly greater than 1 dalton A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

281 | toppr IN Q Type your question the correct answer in the blanks. Answer ( (i)_{6}^{12} C+_{1}^{1} H longrightarrow_{7}^{13} N ) ( (i i)_{13}^{27} A l+_{1}^{1} H longrightarrow_{12}^{24} M g+_{2}^{4} H e ) ( (i i i)_{92}^{235} U+_{0}^{1} n longrightarrow_{56}^{140} B a+_{36}^{93} K r+ ) ( mathbf{3}_{mathbf{0}}^{mathbf{1}} boldsymbol{n} ) ( (i v)_{33}^{75} A s+_{1}^{2} H longrightarrow_{25}^{56} M n+9_{1}^{1} H+ ) ( 12_{0}^{1} n ) ( (boldsymbol{v})_{1}^{2} boldsymbol{H}+_{1}^{3} boldsymbol{H} longrightarrow_{2}^{4} boldsymbol{H} boldsymbol{e}+_{0}^{1} boldsymbol{n} ) Answers: A: Projectile capture B: Spallation C: Fusion D: Projectile capture and particle emission E: Fission Select the correct answers according to the given codes. ( mathbf{A} cdot(i)-A,(i i)-D,(i i i)-E,(i v)-B,(v)-C ) B . ( (i)-D,(i i)-C,(i i i)-A,(i v)-E,(v)-B ) C ( .(i)-A,(i i)-B,(i i i)-C,(i v)-D,(v)-E ) D. ( (i)-E,(i i)-D,(i i i)-C,(i v)-B,(v)-A ) | 12 |

282 | Calculate the energy associated with the following nuclear reaction: [ begin{array}{cc} begin{array}{c} 27 A l \ 26.9815 a m u end{array}+underbrace{2}_{2.0141 a m u}^{2} H \ _{12}^{25} M g & _{2}^{4} H e \ 24.9858 a m u^{+} 4.0026 a m u & end{array} ] | 12 |

283 | ( H_{3} A O_{4} ) has ( 31.6 % ) of “A” by mass. The atomic mass of the atom “A” is: A . 17 B. 3 c. 35.5 D. 40 | 12 |

284 | For a pair production, the minimum frequency of the gamma ray must be: A ( cdot 2.5 times 10^{14} mathrm{Hz} ) B. ( 2.5 times 10^{20} mathrm{Hz} ) C ( cdot 2.5 times 10^{28} mathrm{Hz} ) D. ( 2.5 times 10^{34} mathrm{Hz} ) | 12 |

285 | Neutron ratio(r) (availability for fusion) of an atomic reactor and atom bomb are A. ( r>1 ) in atomic reactor and ( r1 ) in bomb c. ( r>1 ) in both atomic reactor and bomb D. r ( <1 ) in both atomic reactor and bomb | 12 |

286 | A nucleus of atomic number ( Z ) and mass number ( A ) emits a ( beta ) -particle.The atomic number and mass number of resulting nucleus is A. ( Z, A ) B. ( Z+1, A ) c. ( Z, A+1 ) D. ( Z-1, A-1 ) | 12 |

287 | For a sustained chain reaction, the reproduction factor should be: A . zero B. one c. two D. three | 12 |

288 | The fraction of a radioactive material which remains active after time ( t ) is ( mathbf{9} / mathbf{1 6} . ) The fraction which remains active after time ( t / 2 ) will be A ( cdot frac{4}{5} ) B. ( frac{7}{8} ) ( c cdot frac{3}{5} ) D. ( frac{3}{4} ) | 12 |

289 | A radioactive sample decays by ( 63 % ) of its initial value in ( 10 s . ) It would have decayed by ( 50 % ) of its initial value in ( mathbf{A} cdot 7 s ) в. 14 s c. ( 0.7 s ) D. ( 1.4 s ) | 12 |

290 | Calculate the wavelength of ( k_{alpha} ) line for ( Z=31 ) when ( alpha=5 times 10^{7} H z^{1 / 2} ) for a characteristic X-ray spectrum. A ( cdot 1.33 ) a B. 1.33 nm c. ( 133 times 10^{-10} mathrm{m} ) D. 133 пт | 12 |

291 | Among alpha, beta and gamma radiations, which are the ones affected by a magnetic field? | 12 |

292 | In hydrogen bomb we use the process of A. Fusion B. Fission ( c . ) Both (1)( &(2) ) D. None of these | 12 |

293 | A radioactive nucleus has specific binding energy’ ( E_{1} ) ‘. It emits an ( alpha ) particle. The resulting nucleus has specific binding energy’ ( E_{2} ) ‘. Then A ( cdot E_{2}=E_{1} ) в. ( E_{2}E_{1} ) D. ( E_{2}=0 ) | 12 |

294 | The function of heavy water in a nuclear reactor to: A. slow down the neutrons B. increase the neutrons c. stop the electrons D. none of these | 12 |

295 | The nucleus finally formed in fusion of protons in proton-proton cycle is that of A. Heavy hydrogen B. Carbon c. Helium D. Lithium | 12 |

296 | A gaseous mixture contains ( 70 % N_{2} ) and a ( 30 % ) unknown gas, by volume. If the average molecular weight of gaseous mixture is ( 37.60, ) the molecular weight of unknown gas is: A . 42.2 B. 60 c. 40 D. 50 | 12 |

297 | Find the ( Q ) value of the reaction ( N^{14}+alpha rightarrow O^{17}+p ) The masses of ( N^{14}, H e^{4}, p, ) and ( O^{17} ) are respectively, 14.00307 u, ( 4.00260 u ) ( 1.00783 mathrm{u}, ) and ( 16.99913 mathrm{u} . ) Find the total kinetic energy of the products if the striking ( alpha- ) particle has the minimum kinetic energy required to initiate the reaction: | 12 |

298 | Consider a hypothetical annihilation of a stationary electron with a stationary positron. What is the wavelength of the resulting radiation? A ( cdot lambda=frac{h}{2 m_{c} c} ) B. ( lambda=frac{2 h}{m_{c} c^{2}} ) c. ( lambda=frac{h}{2 m_{c} c^{2}} ) D. None of these | 12 |

299 | The nucleus finally formed in fusion of the proton in a proton cycle is that of: A. Helium B. Deuterium c. carbon D. Hydrogen | 12 |

300 | ( 7 / 8 ) fraction of a sample disintegrates in ‘t’ time, how much time it will take to disintegrate ( 15 / 16 ) fraction? ( mathbf{A} cdot mathbf{t} ) B. ( 4 / 3 t ) ( c cdot 5 / 3 t ) D. 2t | 12 |

301 | Identify ( [boldsymbol{A}] ) and ( [boldsymbol{B}] ) in the following: ( underset{89}{297} A c stackrel{-beta}{longrightarrow}[A] quad-alpha ) ( [boldsymbol{B}] stackrel{-boldsymbol{alpha}}{longrightarrow} boldsymbol{R} boldsymbol{n} ) A ( . P o, R n ) в. ( T h, P o ) c. ( R a, T h ) D. ( T h, R a ) | 12 |

302 | What is the mass of one curie of ( U^{234} ? ) A . ( 3.7 times 10^{10} g ) B. ( 3.7 times 10^{-10} g ) c. ( 6.25 times 10^{-34} g ) D. ( 1.438 times 10^{-11} g ) | 12 |

303 | ( 92 U^{238} ) absorbs a neutron. The product emits an electron. This product further emits an electron. The result is ( A cdot_{94} P u^{239} ) В ( cdot_{90} P u^{23} ) ( mathrm{c} cdot_{93} mathrm{Pu}^{237} ) D ( cdot ) ( _{94} P u^{23} ) | 12 |

304 | The mass of deutron ( left(_{1} H^{2}right) ) nucleus is 2.013553 a.m.u. If the masses of proton and neutron are 1.007275 a.m.u. and 1.008665 a.m.u. respectively. Calculate the mass defect, the packing fraction, binding energy and binding energy per nucleon. | 12 |

305 | Assertion Nuclear forces are independent of charges. Reason Nuclear force is not a short range force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

306 | The half-life of a radioactive material is 693 years. Find its decay constant. | 12 |

307 | Assertion (A): All the radioactive elements are ultimately converted into lead Reason (R): All the elements above lead | 12 |

308 | The most common fuel for a fission reaction in a nuclear reactor is: A. Uranium 230 B. Uranium 238 c. Californium 238 D. Thorium 234 | 12 |

309 | For which of the following events will the resulting products have more mass than the mass of the stuff from which the products came? A. Alpha decay B. Beta decay c. An exothermic nuclear reaction D. An endothermic nuclear reaction E. Nuclear fission of uranium -235 | 12 |

310 | The half life of ( S r ) is 28 years. The fraction of the specimen that remains undecayed after 40 years will be A . ( 21 % ) в. 37% c. ( 45 % ) % D. 63 % | 12 |

311 | Assertion Separation of isotope is possible because of the difference in electron numbers of isotope. Reason Isotope of an element can be separated by using a mass spectrometer A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Reason is correct but Assertion is incorrect | 12 |

312 | Three-fourth of the active nuclei present in a radioactive sample decay in ( frac{mathbf{3}}{mathbf{4}} ) second. What Is the half-life of the sample? A. 1 second B. ( frac{1}{2} ) second ( c cdot 3 ) ( frac{3}{4} ) second D. 3 second | 12 |

313 | The binding energies of the nuclei ( A ) and B are ( E_{a} ) and ( E_{b} ) respectively. Three nuclei of the element B fuse to give one nucleus of element A and an energy Q is released. Then, ( E_{a}, E_{b}, Q ) are related as : A ( cdot E_{a}-3 E_{b},=Q ) в. ( 3 E_{b}-E_{a},=Q ) c. ( E_{a}+3 E_{b},=Q ) ( mathbf{D} cdot E_{b}+3 E_{a},=Q ) | 12 |

314 | The number of radioactive nuclei that were present after ( 7 h ) is ( A cdot 2 times 10^{4} ) B . ( 1.25 times 10^{8} ) c. ( 1.875 times 10^{6} ) D. ( 1.25 times 10^{4} ) | 12 |

315 | In an energy emitting nuclear reaction the binding energies of reactants and products are ( e_{1}, e_{2} ) respectively.Then which is correct of the following? ( mathbf{A} cdot e_{1}e_{2} ) D. ( e_{1} geq e_{2} ) | 12 |

316 | A star initially has ( 10^{40} ) deuterons. It produces energy through the processes ( 1 H^{2}+_{1} 1 H^{2} rightarrow_{2} H^{3}+P ) and ( _{1} H^{2}+_{1} rightarrow_{2} ) ( boldsymbol{H} boldsymbol{e}^{boldsymbol{4}} boldsymbol{+} boldsymbol{n} ) If the average power radiated by the star is ( 10^{16} W ), the deutron supply of the star is exhausted in a time of the order of ( A cdot 10^{6} ) B. ( 10^{8} ) ( c cdot 10^{12} ) D. ( 10^{16} ) | 12 |

317 | A radioactive isotope ( boldsymbol{X} ) with half life ( 1.5 times 10^{9} y r ) decays into a stable nucleus ( Y . A ) rock sample contains both elements ( X ) and ( Y ) in ratio ( 1: 15 . ) Find the age of the rock | 12 |

318 | When ( _{3}^{7} mathrm{Li}left(M_{L i}=7.016004 muright) ) is bombarded by a proton two ( alpha ) – particles result. ( left(M_{H e}=4.002603 muright) . ) Find the reaction energy A . 13.35 MeV B. 14.85 MeV c. ( 16.08 mathrm{MeV} ) D. 17.35 MeV | 12 |

319 | An atom which has a mass number of 14 and has 8 neutrons is an: A. isotope of oxygen B. isobar of oxygen c. isotopes of carbon D. isobar of carbon | 12 |

320 | ( frac{228}{88} X-3 alpha-beta longrightarrow Y . ) The element ( Y ) is: ( mathbf{A} cdot_{82}^{216} P b ) в ( cdot ) за้ใ ( P b ) ( mathbf{c} cdot_{83}^{218} B i ) D ( cdot_{83}^{216} B i ) | 12 |

321 | The half-life of radio isotope is 4 hr. If initial mass of the isotope was 200 g, then mass remaining after 24 hr will be A ( .1 .042 mathrm{g} ) B. 2.084 g c. 3.125 g D. 4.167 g | 12 |

322 | The half life of ( ^{58} ) Co is 72 days. The time taken for ( frac{3}{4} t h ) of the initial mass to disintegrate is: A. 144 days B . 235 days c. 344 days D. 433 days | 12 |

323 | A certain radioactive material can undergo three different types of decay, each with a different decay constant ( lambda, 2 lambda ) and ( 3 lambda . ) Then, the effective decay constant ( lambda_{e f f} ) is ( A cdot 6 lambda ) B. ( 4 lambda ) ( c cdot 2 lambda ) D. ( 3 lambda ) | 12 |

324 | The decay constant of radioactive substance is ( 4.33 times 10^{-4} ) per year Calculate its half life period. | 12 |

325 | A fusion reaction consists of combining four protons into an ( alpha ) – particle. The mass of ( boldsymbol{alpha} ) – particle is 4.002603 amu and that of proton is 1.007825 amu This question has multiple correct options ( mathbf{A} cdot ) the equation ( 4 p_{1}^{1} rightarrow H e_{2}^{4} ) does not satisfy conservation of charge B. the correct reaction equation may be ( 4 p_{1}^{1} rightarrow H e_{2}^{4}+ ) ( 2 beta^{+}+2 v ) where ( beta^{+} ) is positron and ( v ) is the neutrino (zero rest mass and uncharged) c. loss of mass in the reaction is ( 0.028697 a m u ) D. the energy equivalent of the mass defect is ( 26.7 mathrm{MeV} ) | 12 |

326 | Atomic weight of boron is 10.81 and it has two isotopes ( _{5} B^{10} ) and ( _{5} B^{11} . ) Then ratio of ( _{5} B^{10}:_{5} B^{11} ) in nature would be A . 19: 81 B. 10: 11 c. 15: 16 D. 81: 19 | 12 |

327 | Carbon has three isotopes with atomic mass no. A ( . ) 10, 11,12 2 1,1,22 ? B. 13, 14, 15 c. 12,13,14 D. 14,15,16 | 12 |

328 | The number of neutrons accompanying the formation of 139 54 ( mathrm{Xe} ) and 94 38 ( mathrm{Sr} ) from the absorption of a slow neutron by 235 92 followed by nuclear fission is: ( A cdot O ) B. 2 ( c ) D. 3 | 12 |

329 | Which of the following isotopes is used for treatment of cancer? A ( cdot C_{o}^{6} ) B. ( K^{4} ) ( c cdot S r^{90} ) D. ( I^{13} ) | 12 |

330 | The half-life of a certain radioactive isotopes is ( 32 h . ) What fraction of a sample would remain after ( 16 h ? ) A . 0.25 в. 0.71 c. 0.29 D. 0.75 | 12 |

331 | Mean life of a radioactive sample is 100 s. Find its half life in minutes A. 0.693 B. ( c cdot 10^{-4} ) D. 1.155 | 12 |

332 | The nuclear reaction, ( _{29}^{63} C u+_{2}^{4} H e longrightarrow_{17}^{37} C l+14_{1}^{1} H+16_{0}^{1} n ) is referred to as: A. spallation reaction B. fusion reaction c. fission reaction D. chain reaction | 12 |

333 | A radioactive isotope of radium placed in the second group in the periodic table emits one ( alpha ) -particle and one ( beta ) particle. The new element formed is in the ( _{-}-ldots_{-}-_{text {roup. }} ) A . first B. second c. third D. fourth | 12 |

334 | Isotopes of an element differ in the. A. atomic number B. Number of nucleons C. Number of neutrons D. Mass number | 12 |

335 | One a.m.u is defined as mass of : A ( cdot frac{1^{t h}}{16} ) the mass of one oxygen atom B. ( frac{1}{14}^{t h} ) the mass of one atom of nitrogen C. ( frac{1}{12}^{text {th }} ) the mass of one carbon-12 D. None of above | 12 |

336 | In the core of nuclear fusion reactor, the gas becomes plasma because of A. strong nuclear force acting between the deuterons B. coulomb force acting between the deuterons c. coulomb force acting between deuteron-electron pairs D. the high temperature maintained inside the reactor ( operatorname{cor} ) | 12 |

337 | The rate of disintegration of a radioactive substance falls from 800dpm to 100dpm in 6 hours. The halflife of the radioactive substance is ( mathbf{A} cdot 6 / 7 h r s ) B. 2 hrs c. 3 hrs D. ( 1 h r ) | 12 |

338 | The binding energy of ( _{17} C l^{35} ) nucleus is ( 298 mathrm{MeV} . ) Find its atomic mass. The mass of hydrogen atom ( left(_{1} boldsymbol{H}^{1}right) ) is 1.008143 a.m.u. Given 1 a.m.u. ( =931 ) ( mathrm{MeV} ) | 12 |

339 | Assertion The electrical conductivity of a gas increases when ( X ) -rays or ( gamma ) -rays pass through it Reason lonization in the gas is produced by ( x ) rays or ( gamma- ) rays A. Assertion is True and Reason is True; Reason is a correct explanation of Assertion B. Assertion is True and Reason is True but Reason is not a correct explanation of Assertion c. Assertion is True and Reason is False D. Assertion is False and Reason is True | 12 |

340 | In the fusion process there are A. isotopes of hydrogen B. isotopes of helium c. isotopes of carbon D. isotopes | 12 |

341 | Fusion reaction take place at high temperature because A. atoms are ionized at high temperature B. molecules break up at high temperatures C . nuclei break up at high temperature D. kinetic energy is high enough to overcome repulsion between nuclei | 12 |

342 | The binding energy per nucleon of ( _{17}^{35} C l ) nucleus is ( left(_{17}^{35} C l=34.98000 mathrm{amu}, m_{P}=1.007825right. ) ( operatorname{amu,m}_{n}=1.008665 ) amu and 1 amu is equivalent to ( 931 mathrm{MeV} ) ) A ( .4 .6 mathrm{MeV} ) B. ( 5.8 mathrm{MeV} ) c. ( 6.5 mathrm{MeV} ) D. ( 8.2 mathrm{MeV} ) | 12 |

343 | Which of the following is an ( (n . p) ) reaction? A ( cdot frac{13}{5} C+frac{1}{1} C longrightarrow_{6}^{14} C ) B ( cdot frac{4}{7} N+frac{1}{1} H rightarrow_{8}^{15} O ) C・ ( 133 l+frac{1}{0} n rightarrow 27 M g+1 ) ( 13 A l+0 ) D ( cdot frac{235}{92} U+_{1}^{0} N longrightarrow_{54}^{140} X e+_{38}^{94} S r+_{30}^{1} n ) | 12 |

344 | The mass defect of ( _{2}^{4} H e ) is ( 0.03 u . ) The binding energy per nucleon of helium ( (text { in } M e V) ) is A . 69.825 B. 6.9825 c. 2.793 D. 27.93 | 12 |

345 | The atomic weight of uranium isotope, which is equally fissionable is : A . 235 в. 238 c. 234 D. 236 | 12 |

346 | Plutonium decays with a half life of 24,000 years. If plutonium is stored for 72,000 years, the fraction that remains is: A. ( 1 / 2 ) в. 1/4 c. ( 1 / 6 ) D. ( 1 / 8 ) | 12 |

347 | A beam of ( 16 M e V ) deutrons from a cyclotron falls on a copper block. The beam is equivalent to a current of ( 15 mu A ) At what rate do the deutrons strike the block? A ( cdot 9.4 times 10^{9} ) B. ( 9.4 times 10^{7} ) c. ( 9.4 times 10^{11} ) D. ( 9.4 times 10^{13} ) | 12 |

348 | When two deuterium nuclei fuse together to form a tritium nucleus, we ( operatorname{get} a ) A. neutron B. deuteron c. alpha particle D. proton | 12 |

349 | Write the relation for binding energy (B.E) (in MeV) of a nucleus of mass ( _{Z}^{A} M ) atomic number ( (z) ) and mass number (A) in terms of the masses of its constituents – neutrons and protons. | 12 |

350 | A rock is ( 12.5 times 10^{9} ) years old. The rock contains ( ^{238} U ) which disintegrates to form ( ^{206} U . ) Assume that there was no ( ^{206} P b ) in the rock initially and it is the only stable product formed by the decay The ratio of number of nuclei of ( ^{238} U ) to that of ( ^{206} P b ) in the rock is ( frac{1}{2^{1 / x}-1} ) Find ( x ) (Approximately). Half-life of ( ^{238} boldsymbol{U} ) is ( 4.5 times 10^{9} ) years.( left(2^{1 / 3}=1.259right) ) | 12 |

351 | When the reactor shuts down why does it require cooling? A. To cool the reactor from chain reaction B. To cool the reactor from fission reaction c. Both (1) and (2) D. None of these | 12 |

352 | One gram of radium is reduced by ( 2 m g ) in 5 years by ( alpha ) – decay. The half life of radium is: ( left(log _{10} 998=2.9991right) ) A. 1520.4 years B. 1671.7 years c. 1617.5 years D. 1732.86 years | 12 |

353 | When a radioactive nucleus emits a ( beta ) particular, the proton- neutron ratio A . decreases B. increases c. remains same D. first decreases and increases | 12 |

354 | How is nuclear energy released in a fission process? How is this energy converted into electric energy? | 12 |

355 | n Kaiga Atomic Power reactor plant, the fuel that can be used is A. coal B. Uranium c. Petrol D. Natural gas | 12 |

356 | Assertion (A) : Due to annihilation of electron positron pair, at least ( 2 gamma ) -ray photons are produced. Reason (R) : This is in accordance with conservation of linear momentum. A. Both A & R are true and R is the correct explanation of ( A ) B. Both A & R are true and R is not correct explanation of C. A is true but R is false D. A is false but R is true | 12 |

357 | An atom of ( _{53}^{131} I ) and an atom of ( _{53}^{127} I ) contain the same number of: A. Quarks B. Neutrons c. Nucleons D. Protons | 12 |

358 | How many neutrons result from the following fission reaction? ( mathbf{A} cdot mathbf{1} ) B. 2 ( c cdot 3 ) D. 4 ( E .5 ) | 12 |

359 | ( _{1} H^{1},_{1} H^{2},_{1} H^{3} ) are : A. isotopes B. isotones c. isobars D. isotherms | 12 |

360 | The nucleus obtained after ( alpha ) -emission from the nucleus ( _{y} mathbf{A}^{x} ) is A・ ( _{y-2} mathrm{B}^{x-2} ) В. ( _{y+2} mathrm{B}^{x+4} ) ( mathbf{c} cdot_{y} mathbf{B}^{x} ) D. ( _{y-2} mathrm{B}^{x-4} ) | 12 |

361 | The half-life of a radio-isotope is ( 4 h r . ) If initial mass of the isotope was ( 200 g ), then mass remaining after ( 24 h r ) will be A . ( 1.042 g ) в. ( 2.084 g ) c. ( 3.125 g ) D. ( 4.167 g ) | 12 |

362 | The material used to slow the neutrons in a reactor is called A. Control rod B. Moderator c. Fuel D. Heat exchanger | 12 |

363 | An element ( X ) decays into element ( Z ) by two-step process. [ begin{array}{l} boldsymbol{X} longrightarrow boldsymbol{Y}+_{2}^{4} boldsymbol{H} boldsymbol{e} \ boldsymbol{Y} longrightarrow Z+2 bar{e} text { then } end{array} ] ( A cdot X ) and ( Z ) are isobars B. ( X ) and ( Y ) are isotopes c. ( X ) and ( Z ) are isotones D. ( X ) and ( Z ) are isotopes | 12 |

364 | In plants and animals, the ratio of ( mathrm{C}^{14} ) to ( C^{12} ) is | 12 |

365 | The mass defect of a certain nucleus is found to be 0.03 amu. Its binding energy is: A. 27.93 ev B. 27.93 kev c. 27.93 Mev D. 27.93 Gev | 12 |

366 | The nuclei having same number of protons but different number of neutrons are called A. Isobars B. ( alpha ) -particles c. Isotopes D. ( gamma ) -particles | 12 |

367 | ILLUSTRATION 30.11 On disintegration of one atom of 235U, the amount of energy obtained is 200 MeV. The power obtained in a reactor is 1000 kilowatt. How many atoms are disintegrated per second in the reactor? What is the decay in mass per hour? | 12 |

368 | For a fast chain reaction, the size of ( U^{235} ) block, as compared to its critical size, must be A. greater B. smaller c. same D. anything | 12 |

369 | ( underbrace{left[begin{array}{l}E \ L \ Lend{array}right.} ) | 12 |

370 | Among the following, which one is isotope A. ( N H_{3} ) and ( N_{2} H_{4} ) B. 160 and ( ^{17} O ) c. ( N H_{4} C l ) and ( N H_{4} N O_{3} ) D. ( C H_{3} O C H_{3} ) and ( C H_{3} C H_{2} O H ) E. ( O_{2} ) and ( O_{3} ) | 12 |

371 | ( 1 mathrm{u} ) is equivalent to an energy of ( A cdot 9.315 mathrm{MeV} ) B. 931.5 Kev c. 93.15 Mev D. 931.5 Mev | 12 |

372 | In an atom bomb, the energy is released because of the: A. chain reaction of neutrons and ( _{92} U^{23} ) B. chain reaction of neutrons and ( _{text {g2 }} U^{23} ) C. chain reaction of neutrons and ( _{text {y } 2} U^{236} ) D. chain reaction of neutrons and ( _{92} U^{24} ) | 12 |

373 | A freshly prepared radioactive source of half-life ( 2 h ) emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is ( mathbf{A} cdot 6 h ) B. ( 12 h ) ( c .24 h ) D. ( 28 h ) | 12 |

374 | 20. Consider one of fission reactions of 238U by thermal neutrons 32 U+ n S r + 540 Xe + 2n. The fission fragments are however unstable and they undergo successive B-decay until 3: Sr becomes 20 Zr and 540 Xe becomes 50 Ce. The energy released in this process is Given: m(23SU) = 235.439 u, m (n) = 1.00866 u, m (94Zr) = 93.9064 u, m(140Ce) = 139.9055 u, 1 u = 931 MeV] (a) 156 MeV (b) 208 MeV (c) 456 MeV (d) cannot be computed | 12 |

375 | Range of nuclear force is approximately A ( cdot 2 times 10^{-15} m ) B . ( 1.5 times 10^{-20} m ) c. ( 7.2 times 10^{-4} m ) D. ( 1.4 times 10^{-15} mathrm{m} ) | 12 |

376 | Fill in the blanks. The most dangerous radiation released by radioactive materials is | 12 |

377 | What is the biggest advantage of nuclear energy? A. It is clean. B. Huge amount of energy is produced. C. The radioactive emissions from a nuclear power plant are healthy. D. Nuclear power plant can be easily set up in urban areas. | 12 |

378 | Assertion (A): Nuclear fusion reactions are considered as thermo-nuclear reactions Reason (R): The source of stellar energy is nuclear fusion A. Both A & R are true and R is the correct explanation of ( A ) B. Both A & R are true and R is not correct explanation of ( A ) c. ( A ) is true but ( R ) is false D. A is false but R is true | 12 |

379 | Assertion The reactions taking place in the sun are nuclear fusion reactions. Reason The main reason for nuclear fusion reactions in the sun is that ( boldsymbol{H}_{2} ) is present in the sun’s atmosphere so that hydrogen nuclei can fuse to form helium. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

380 | Which of the following has an equal number of neutrons and protons? A. Hydrogen B. Deuterium c. Fluorine D. Chlorine | 12 |

381 | A freshly prepared sample of a radioisotopes of half-life ( 1386 s ) has activity ( 10^{3} ) disintegrations per second. Given that ( ln 2=0.693 ), the fraction of the initial number of nuclei (expressed in nearest percentage) that will decay in the first ( 80 s ) after preparation of the sample is | 12 |

382 | ( 8 g ) of divalent metal produces ( 9.8 g ) of its nitride. The approx atomic weight of metal is: A . 9.8 B. 42 ( c .35 ) D. | 12 |

383 | ( ^{57} ) Co decays by electron capture. Its half life is 272 days. Find the activity left after a year if present activity is ( 2 mu C i ) A. ( 0.788 mu ) Ci B. ( 0.431 mu C i ) ( mathbf{c} .0 .39 mu mathrm{Ci} ) D. none of these | 12 |

384 | What are the precautions to be taken by the people who are working in radiation laboratories? | 12 |

385 | What is meant by radioactivity? | 12 |

386 | There are ( _{—} ) isotopes of chlorine. A. 0 B. ( c cdot 2 ) D. | 12 |

387 | The average binding energies of deuterium and ( alpha ) -particle are ( 1.12 mathrm{MeV} ) and ( 7.1 mathrm{MeV} ) respectively. The energy that liberates in the reaction ( _{1} H^{2}+_{1} H^{2} ) ( rightarrow_{2} H e^{4} ) is MeV. ( mathbf{A} cdot 23.92 ) B . 25 c. 25.6 D. 15.8 | 12 |

388 | Consider the following nuclear reactions: ( 238 M longrightarrow_{y}^{x} N+2_{2}^{4} H e ) ( 92^{B} M ) ( boldsymbol{y}^{boldsymbol{x}} boldsymbol{N} longrightarrow_{boldsymbol{B}}^{boldsymbol{A}} boldsymbol{L}+boldsymbol{2} boldsymbol{beta}^{+} ) the number of neutrons present in the element ‘ ( L^{prime} ) is: A .142 в. 144 c. 140 D. 146 | 12 |

389 | As the mass number A varies which of the quantity related to nucleus does not change A . mass B. volume c. binding energy D. density | 12 |

390 | In which of the following do two lighter atoms combine to form one heavier atom? A. Radioactive tracer B. Radioactive carbon dating c. Radiation therapy D. Nuclear fission E. Nuclear fusion | 12 |

391 | Which of the following notations shows the product incorrectly? ( mathbf{A} cdot_{96} C m^{242}(alpha, 2 n)_{97} B k^{243} ) В. ( _{5} B^{10}(alpha, n)_{7} N^{13} ) ( mathbf{C} cdot_{7} N^{14}(n, p)_{5} C^{14} ) D. ( _{14} S i^{28}(d, n)_{15} P^{29} ) | 12 |

392 | Match the following | 12 |

393 | Natural radioactivity was discovered by A. Marie Curie B. Ernest Rutherford C. Henri Becquerel D. Enrico Fermi | 12 |

394 | Critical mass of ( _{92} U^{235} ) is nuclear fission is : A. 1 to ( 100 mathrm{g} ) B. 100 to ( 1000 mathrm{mg} ) c. 1 to ( 100 mathrm{kg} ) D. 1 to 100 u | 12 |

395 | What does a neutron decays to? ( mathbf{A} cdot ) one ( p, ) one ( v ) one ( beta^{+} ) B. one ( beta+, ) one ( beta- ) and ( v ) C . one ( p ), one ( beta^{-} ) and one ( bar{v} ) D. all the above | 12 |

396 | The purpose of using heavy water in nuclear reactor is: A. to cool the reactor to room temperature B. to make the dynamo blades to work well C. to decrease the energy of fast neutrons D. to increase the energy released in nuclear fission | 12 |

397 | Does the composition of nucleus changes, if it emits ( gamma ) -radiation? A . yes B. no c. may be D. cant say | 12 |

398 | 45. The half-life period of RaB(Pb214) is 26.8 min. The mass of one curie of RaB is (a) 3.71 x 100 g (b) 3.71 x 10-10 g (c) 8.61 1010 g (d) 3.064 x 10-8 g | 12 |

399 | Structures of ( ^{235} U ) and ( ^{238} U ) differ by three : A. isotopes B. neutrons c. electrons D. protons | 12 |

400 | A nuclear reaction is given as ( boldsymbol{p}+^{15} boldsymbol{N} rightarrow_{Z}^{A} boldsymbol{X}+boldsymbol{n} ) Find, ( A, Z ) and identify the nucleus ( X ) | 12 |

401 | Results of calculations for four different designs of a fusion reactor using D-D reaction are given below. Which of these is most promising based on Lawson criterion? A. Deuteron density =2.0 ( times 10^{12} mathrm{cm}^{-3} ), confinement ( operatorname{tim} e=5.0 times 10^{-3} mathrm{s} ) B. Deuteron density=8.0 ( times 10^{14} mathrm{cm}^{-3} ), confinement ( operatorname{time}=9.0 times 10^{-1} mathrm{s} ) c. Deuteron density ( =4.0 times 10^{23} mathrm{cm}^{-3} ), confinement ( operatorname{time}=1.0 times 10^{-11} mathrm{s} ) D. Deuteron density=1.0 ( times 10^{24} mathrm{cm}^{-3} ), confinement ( operatorname{time}=4.0 times 10^{-12} mathrm{s} ) | 12 |

402 | Thermal neutrons are those which A. are at very high temperature B. move with high velocities C. have kinetic energies similar to those of the surroundings molecules D. are at rest | 12 |

403 | The necessary condition for nuclear fusion is A. high temperature and high pressure B. low temperature and low pressure c. high temperature and low pressure D. low temperature and high pressure | 12 |

404 | Assertion Heavy nuclides tend to have more number of neutrons than protons. Reason In heavy nuclei, as there is coloumbic repulsion between protons, so excess of neutrons are preferable. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

405 | Binding energy per nucleon of ( _{1} H^{2} ) and ( _{2} H e^{4} ) are ( 1.1 M e V ) and ( 7.0 M e V ) respectively. Energy released in the process ( _{1} H^{2}+_{1} H^{2} longrightarrow_{2} H e^{4} ) is A. ( 20.8 mathrm{MeV} ) в. ( 16.6 mathrm{MeV} ) c. ( 25.2 mathrm{MeV} ) D. ( 23.6 mathrm{MeV} ) | 12 |

406 | Let ( E_{1} ) and ( E_{2} ) be the binding energies of two nuclei ( A ) and ( B . ) It is observed that two nuclei of A combine together to form a B nucleus. This observation is correct only if A ( cdot E_{1}>E_{2} ) в. ( E_{2}>E_{1} ) c. ( E_{2}<2 E_{1} ) D. nothing can be said | 12 |

407 | A completely air tight container contains 100 grams of radioactive material.After 24days, only 12.5 grams of radioactive material left in the bottle.Calculate the half-life of this radioactive material? A. 24 days B. 16 days c. 12 days D. 8 days E. 3 days | 12 |

408 | How many moles of electron weight one kilogram? в. ( frac{1}{9.108} times 10^{3} ) c. ( frac{6.023}{9.108} times 10^{54} ) D. ( frac{1}{9.108 times 6.023} times 10^{8} ) | 12 |

409 | Two half life radioactive substance is 20 minutes. The approximate time interval ( left(t_{2}-t_{1}right) ) between the time ( t_{2} ) when ( frac{2}{3} ) of it has decayed and time ( t_{1} ) and ( frac{1}{3} ) of it had decayed is: A . 14 min B. 20 min ( c .28 ) min D. 7 min | 12 |

410 | Which reaction is responsible for solar energy? Name the major component of solar energy that reaches us. | 12 |

411 | The nuclear radius is given by ( boldsymbol{R}= ) ( r_{0} A^{1 / 3}, ) where ( r_{0} ) is constant and ( A ) is the atomic mass number. Then : A. The nuclear mass density of ( U^{238} ) is twice that of ( S n^{119} ) B. The nuclear mass density of ( U^{238} ) is thrice that of ( S n^{11} ) C. The nuclear mass density of ( U^{238} ) is the same as that of ( S n^{11} ) D. The nuclear mass density of ( U^{238} ) is half that of ( S n^{119} ) | 12 |

412 | In the nuclear reaction presented above, the “other particles” might be A. an alpha particle, which consists of two protons and neutrons B. two protons c. one protons and one neutron D. two neutrons | 12 |

413 | A radioactive sample contains ( 2.3 mathrm{mg} ) of pure ( _{6}^{11} C ) which has half-life period of 1224 second. Calculate i) the number of atoms present initially ii) the activity when ( 5 mu g ) of the sample will be left. | 12 |

414 | At what rate, in mega gram per minute, must hydrogen be consumed in fusion reaction to provide the sun with the energy it radiates? (Take mass defect per reaction to be 0.028706 a.m.u) A . ( 3.66 times 10^{14} ) mega gram ( min ^{-1} ) B. ( 3.66 times 10^{16} ) mega gram ( min ^{-1} ) C. ( 3.66 times 10^{15} ) mega gram ( min ^{-1} ) D. 3.66 ( times 10^{10} ) mega gram ( min ^{-1} ) | 12 |

415 | A nuclear transformation is denoted by ( X(n, alpha) rightarrow_{3} L i^{7} . ) The nucleus of element ( X ) is ( A cdot_{6} C^{12} ) B ( cdot_{5} B^{10} ) ( mathbf{c} cdot_{5} B^{9} ) ( mathbf{D} cdot_{4} B e^{1} ) | 12 |

416 | Assertion Magnesium has two isotopes ( _{12}^{24} M g ) and ( _{12}^{26} M g . ) According to which isotopes of magnesium have different mass numbers. Reason Different mass number of isotopes is due to the difference in neutrons no. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

417 | High energy neutrons are used in a nuclear reactor to initiate the fission reaction. A. True B. False | 12 |

418 | When an energetic ( gamma ) -ray photon falls on heavy substance, an electron and positron produced. The least energy required for t process is A .4 .8 Mav B. 1.02 Mev c. 7.3 Mev D. 10 Mev | 12 |

419 | At a given instant, there are ( 25 % ) undecayed radioactive nuclei in a sample. After ( 10 mathrm{s} ), the number of undecayed nuclei reduces to ( 12.5 % ) Calculate (a) mean life of the nuclei and (b) the time in which the number of decayed nuclei will further reduce to ( 6.25 % ) of the reduced number | 12 |

420 | In the uranium radioactive series, the initial nucleus is ( _{92} U^{238} ) and that the final nucleus is ( _{82} P b^{206} . ) When uranium nucleus decays to lead the number of ( alpha ) particles and ( beta- ) particles emitted are: A. ( 8 alpha, 6 beta ) в. ( 6 alpha, 7 beta ) c. ( 6 alpha, 8 beta ) D. ( 4 alpha, 3 beta ) | 12 |

421 | Find the uncertainty in mass. A ( cdot 1.4 times 10^{-35} mathrm{kg} ) в. ( 2.6 times 10^{-11} mathrm{kg} ) c. ( 2.6 times 10^{-13} k g ) D. ( 8 times 10^{-14} mathrm{kg} ) | 12 |

422 | Which of the following represents the relative penetrating power of the three types of radioactive emission in decreasing order? ( mathbf{A} cdot beta>alpha>gamma ) В ( cdot beta>gamma>alpha ) ( mathbf{c} cdot gamma>alpha>beta ) D ( cdot gamma>beta>alpha ) | 12 |

423 | What parameter is used to measure the stability of a nucleus? A. Average binding energy B. No. of protons c. No. of neutrons D. No. of electrons | 12 |

424 | A nuclear reaction is given as ( boldsymbol{p}+^{15} boldsymbol{N} rightarrow_{Z}^{A} boldsymbol{X}+boldsymbol{n} ) Find the ( Q ) value of the reaction | 12 |

425 | A star initially has ( 10^{40} ) deuterons. It produces energy via the processes ( _{1} H^{2}+_{1} H^{2} rightarrow_{1} H^{3}+p ) and ( _{1} H^{2}+_{1} ) ( H^{3} rightarrow_{2} H e^{4}+n . ) If the average power radiated by the star is ( 10^{16} mathrm{W} ), the deuteron supply of the star is exhausted in a time of the order of [The mass of nuclei are as follows: ( boldsymbol{M}left(boldsymbol{H}^{2}right)=mathbf{2 . 0 1 4} boldsymbol{a m} boldsymbol{u}, boldsymbol{M}(boldsymbol{n})= ) ( mathbf{1 . 0 0 8 a m u} ) ( M(p)=1.007 a m u, Mleft(H e^{4}right)= ) ( 4.001 a m u} ) A ( cdot 10^{6} s ) B . ( 10^{8} ) s ( c cdot 10^{12} s ) ( s ) D. ( 10^{16} s ) | 12 |

426 | The World Nuclear Association considers used fuel management to be sustainable if it meets the following key criteria: A. It covers all the steps of used fuel management from the generation of used fuel up to and including final disposal in accordance with a well defined practical plan. B. It proves to be feasible with a sustainable impact level C. It protects human health and the environment and has no greater impact on the health of future generations than is allowed today. D. It is able to demonstrate to a practicable extent that it is technically and economically viable. E. All of the above | 12 |

427 | Choose the correct statement: A. A nucleus is relatively more stable for which total binding energy is more. B. A nucleus is relatively more stable for which binding energy per nucleon is more. C. A nucleus is relatively more stable for which total binding energy is low. D. None of these | 12 |

428 | In the core of nuclear fusion reactor, the gas becomes plasma because of A. strong nuclear force acting between the deuterons B. Coulomb force acting between the deuterons c. coulomb force acting between deuteron-electron pairs D. the high temperature maintained inside the reactor ( operatorname{cor} ) | 12 |

429 | In nuclear fission, ( 0.1 % ) mass is converted into energy. The energy released in the fission of ( 1 mathrm{Kg} ) mass in KWH is A ( .2 .5 times 10^{5} ) B . ( 2.5 times 10^{7} ) c. ( 2.5 times 10^{9} ) D. ( 2.5 times 10^{-7} ) | 12 |

430 | Nuclear Fission is best explained by: A. Liquid droplet theory B. Yukawa – meson theory C. Independent particle model of the nucleus D. Proton-proton cycle | 12 |

431 | The radioactivity in any nucleus is measured in A. Curie B. Rutherford c. Both D. Newton | 12 |

432 | The control rods in the reactor of a nuclear power plant are made of A. radium B. strontium c. barium D. boron | 12 |

433 | The half life of radium is 1600 years. The time ( 1 g m ) of radium take to reduce to ( 0.125 g m ) is: A. 4800 years B. 4500years c. 5000 years D. 4750 years | 12 |

434 | The activity of a nuclide is 15 millicurie. If its decay constant is ( 0.005 mathrm{sec}^{-1} ), the number of atoms present in it is A. ( 11.1 times 10^{10} ) B . ( 1 times 10^{9} ) c. ( 111 times 10^{10} ) D. ( 1.1 times 10^{10} ) | 12 |

435 | The true statement among following is: A. Energy released per nucleon is same in both fission and fusion reaction B. Energy released per nucleon is more in fission than in fusion reaction C. Energy released per nucleon is less in fission than in fusion reaction D. No energy is released in fusion reaction | 12 |

436 | The following deuterium reactions and corresponding reaction energies are found to occur ( ^{14} N(d, p)^{15} N, Q=8.53 M e V ) ( ^{15} N(d, alpha)^{13} C, Q=7.58 M e V ) ( ^{13} C(d, alpha)^{11} B, Q=5.16 M e V ) The rotation ( ^{14} N(d, p)^{15} N ) represents the reaction ( ^{14} N+d rightarrow^{15} N+p ) ( _{2}^{4} boldsymbol{H} boldsymbol{e}=boldsymbol{4} . boldsymbol{0} boldsymbol{0} 2 boldsymbol{6} boldsymbol{a} boldsymbol{m} boldsymbol{u}_{, 1}^{2} boldsymbol{H} e= ) ( 2.014 a m u_{, 1}^{1} H=1.0078 a m u, n= ) ( mathbf{1 . 0 0 8 7 a m u}(mathbf{1 a m u}=mathbf{9 3 1 M e V}) ) The Q values of the reaction ( ^{11} boldsymbol{B}(boldsymbol{alpha}, boldsymbol{n})^{14} boldsymbol{N} ) is A. ( 0.5 e V ) в. 0.5 Ме ( V ) c. ( 0.05 mathrm{MeV} ) D. ( 0.05 e V ) | 12 |

437 | Assertion It is desirable to slow down fast moving neutrons to sustain controlled chain reactions. Reason Slow moving neutrons efficiently collides with ( U^{235} ) A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

438 | The activity of a radioactive substance is ( R_{1} ) at time ( t_{1} ) and ( R_{2} ) at time ( t_{2}left(>t_{1}right) ) Its decay constant is ( lambda ). Then A ( . R_{1} t_{1} ) B ( cdot R_{2}=R_{1} e^{lambdaleft(t_{1}-t_{2}right)} ) c. ( frac{R_{1}-R_{2}}{t_{2}-t_{1}}= ) constant D. ( R_{2}=R_{1} e^{lambdaleft(t_{2}-t_{1}right)} ) | 12 |

439 | A radioactive isotope decays as ( z A^{n} rightarrow z-2 B^{m-4} rightarrow z-1 C^{m-4} . ) The half lives of ( A ) and ( B ) are 6 months and 10 months respectively. Assuming that initially only ( A ) was present, will it be possible to achieve radioactive equilibrium for ( B ). If ( s o, ) what would be the ratio of nuclei of ( A ) and ( B ) at equilibrium. What would happen if the half lives of ( A ) and ( B ) were 10 month and 6 month. | 12 |

440 | ( 20 % ) of a radioactive element disintegrates in 1 hr.The percentage of the radioactive element disintegrated in ( 2 h r s ) will be A . ( 36 % ) B. 64% c. ( 60 % ) D. 40% | 12 |

441 | 72. The minimum frequency of a y-ray that causes a deuteron to disintegrate into a proton and a neutron is (m, = 2.0141 amu, m,=10078 amu, m = 1.0087 amu.) (a) 2.7 x 1020 Hz (b) SAX 10″ Hz (c) 10.8 x 1020 Hz (d) 21.6 102 HZ | 12 |

442 | The half life period of ( N^{13} ) is 10.1 minute. Its mean life time is : A. 5.05 minutes B. 20.2 minutes c. ( frac{10.1}{0.6931} ) minutes D. Infinity | 12 |

443 | During a nuclear fission reaction A. a heavy nucleus breaks into two fragments by itself B. a light nucleus bombared by thermal neutrons breaks ( u p ) C . a heavy nucleus bombared by thermal neutrons breaks up D. two light nuclei combine to give a heavier nucleus and possibly other products | 12 |

444 | Which of the following sometimes requires initiation from a neutron? A. nuclear fission B. radiation therapy c. radioactive tracer D. radioactive carbon dating | 12 |

445 | The functions of the reflectors in nuclear power plant is that: A . It reflects the neutrons that are escaping from the case B. It reflects the radiation escaping the case of the reactor c. Both (1) and (2) D. It accelerates the reaction | 12 |

446 | From the given table, which properties of the undetected third particle can we calculate? A. Total energy, but not kinetic energy. B. Kinetic energy, but not total energy. c. Both total energy and kinetic energy D. Neither total energy nor kinetic energy. | 12 |

447 | In the nuclear reaction ( frac{14}{7} boldsymbol{N}+_{2}^{4} boldsymbol{H} e rightarrow_{8}^{17} boldsymbol{O}+ldots ldots ldots ldots ) What is the missing particle? A ( cdot frac{4}{2} mathrm{He} ) B . ( _{1}^{1} H ) c. ( _{0}^{1} n ) ( D ) | 12 |

448 | Which of the following radiations are not emitted by electron transitions in atoms ? A. Ultra-violet. B. Infra-red radiations c. visible rays. D. ( alpha ) -rays | 12 |

449 | Large energy released in atomic bomb explosion is mainly due to: A. conversion of heavier to lighter atoms B. products having lesser mass than initial substance c. release of neutrons D. release of electrons | 12 |

450 | Which source of energy is used in a nuclear power station to generate electrical energy? A. Different types of atom regrouping B. Heavy nuclei splitting c. Radioactive isotopes decaying D. Radioactive atoms emitting ( beta ) -particles | 12 |

451 | One curie is equal to ( mathbf{A} cdot 3.7 times 10^{10} ) disintegration/sec B. ( 3.2 times 10^{8} ) disintegration/sec C ( .2 .8 times 10^{10} ) disintegration/sec D. None of these | 12 |

452 | What is the molar mass of ammonium carbonate ( left(N H_{4}right)_{2} C O_{3} ? ) A. ( 48.06 g / ) mol B. ( 96.11 g / ) mol c. ( 82.09 g / ) mol D. ( 78.05 g / ) mol E . ( 192.2 g / ) mol | 12 |

453 | A neutron decays to form a proton. Which particle is not involved in the decay process? A. Antineutrino B. Down quark c. Positron D. Up quark | 12 |

454 | The principle of controlled chain reaction is used in: A. atomic energy reactor B. atom bomb c. the core of sun D. artificial radioactivity | 12 |

455 | What is the half life of a radioactive substance if it has a count rate of 500 counts/sec and 62.5 counts/sec two hours later? A . 10 min B. 20 min c. 30 min D. 40 min E. 50 min | 12 |

456 | Let us consider emission of ( alpha ) -particle from uranium nucleus: ( mathbf{9}_{2} boldsymbol{U}^{2 mathbf{3 5}} rightarrow_{mathbf{2}} boldsymbol{H} boldsymbol{e}^{mathbf{4}} rightarrow mathbf{9 0} boldsymbol{T} boldsymbol{h}^{mathbf{2 3 1}} ) ( boldsymbol{e}=mathbf{9 2} quad boldsymbol{e}=mathbf{0} quad boldsymbol{e}=mathbf{9 0} ) ( boldsymbol{p}=mathbf{9 2} quad boldsymbol{p}=mathbf{2} quad boldsymbol{p}=mathbf{9 0} ) ( boldsymbol{n}=mathbf{1 4 3} quad boldsymbol{n}=mathbf{2} quad boldsymbol{n}=mathbf{1 4 1} ) Shortage of two electrons in thorium is due to: This question has multiple correct options A. conversion of electron to positron B. combination with positron to evolve energy c. annihilation D. absorption in the nucleus | 12 |

457 | Define one Curie. | 12 |

458 | Using ( boldsymbol{E}=boldsymbol{m} boldsymbol{c}^{2}, ) find out the energy released, when ( 2 u ) of mass is destroyed completely Take ( 1 boldsymbol{u}=mathbf{1 . 6 6} times mathbf{1 0}^{-mathbf{2 7}} mathbf{k g} ) A. ( 4.65 mathrm{MeV} ) B. ( 3627 mathrm{MeV} ) c. ( 91.5 mathrm{MeV} ) D. ( 1865 M e V ) | 12 |

459 | Critical mass is minimum mass necessary for A. chain reaction B. fusion c. hydrogen bomb D. all of the above | 12 |

460 | The binding energy per nucleon for the parent nucleus is ( mathrm{E}_{1} ) and that for the daughter nuclei is ( mathrm{E}_{2} ). Then A ( cdot mathrm{E}_{2}=2 mathrm{E}_{1} ) в. ( mathrm{E}_{1}>mathrm{E}_{2} ) c. ( mathrm{E}_{2}>mathrm{E}_{1} ) D. ( mathrm{E}_{1}=2 mathrm{E}_{2} ) | 12 |

461 | Consider a nuclear reaction ( boldsymbol{A}+boldsymbol{B} rightarrow ) C. A nucleus A moving with kinetic energy of 5 MeV collides with a nucleus B moving with kinetic energy of 3 MeV and forms a nucleus ( C ) is excited state. Find the kinetic energy of nucleus ( C ) just after its formation if it is formed in a state with excitation energy ( 10 mathrm{MeV} ) Take masses of nuclei of ( A, B, ) and ( C ) as 25.0,10.0,34.995 amu, respectively. ( left(1 a m u=930 M e V / c^{2}right) ) | 12 |

462 | The discovery of neutron was made on the basis of conservation principle of A. momentum B. momentum and energy c. charge D. charge and energy | 12 |

463 | Which of the following nuclear reactions is not possible? A ( cdot frac{12}{6} C+_{6}^{12} C longrightarrow_{10}^{20} N e+_{2}^{4} H e ) B . ( _{4}^{9} B e+_{1}^{1} H rightarrow_{3}^{6} L i+_{2}^{4} H e ) C ( cdot frac{11}{5} B e+_{1}^{1} H rightarrow_{4}^{9} B e+_{2}^{4} H e ) D. ( _{3}^{7} L i+_{2}^{4} H e longrightarrow_{1}^{1} H+_{4}^{10} B ) | 12 |

464 | The ( beta ) – particles emitted by the radioactive substances are A. positively charged B. negatively charged C. charge less D. positively charged in some substances and negatively charged in others | 12 |

465 | 16. The intensity of gamma radiation from a given source is 1. On passing through 36 mm of lead, it is reduced to 1/8 The thickness of lead which will reduce the intensity to 1/2 will be (a) 12 mm (b) 18 mm (c) 9 mm (d) 6 mm (AIEEE 2005) | 12 |

466 | Which of the following is used as standard for determination of atomic mass? ( mathbf{A} cdot O^{16} ) B. ( C^{12} ) ( c cdot H^{1} ) D. ( O^{1} ) | 12 |

467 | Select the pairs of isotopes, isobars and isotones from the following nuclei ( _{11} N a_{12}^{22}, M g_{111}^{24} N a_{10}^{24} N e^{23} ) | 12 |

468 | A substance has a half-life of 5 years Find out how much of the initial sample remains after 10 years? A. one-fourth (1/4) B. one-sixteenth (1/16) c. one-half ( (1 / 2) ) D. one-fifth (1/5) E . one-eighth (1/8) | 12 |

469 | A metal oxide has the formula ( M_{2} O_{3} ). It can be reduced by ( boldsymbol{H}_{2} ) to give free metal and water. ( 0.15 % ) g of ( M_{2} O_{3} ) required 6 mg of ( boldsymbol{H}_{2} ) for complete reduction. The atomic mass of the metal is: A. 27.9 B. 79.8 ( c . ) 55.8 D. 159.8 | 12 |

470 | A radioactive nucleus with decay constant ( 0.5 / s ) is being produced at a constant rate of 100 nuclei/s. If at ( t= ) 0 there were no nuclei, the time when there are 50 nuclei is A . ( 1 s ) B. ( 2 ln left(frac{4}{3}right) ) s ( c cdot ln 2 ) D. ( ln left(frac{4}{3}right) ) s | 12 |

471 | If the distance between nuclei is ( 2 times ) ( 10^{-13} mathrm{cm}, ) the density of nuclear material is A ( .3 .21 times 10^{-12} k g / m^{3} ) B . ( 1.6 times 10^{-3} mathrm{kg} / mathrm{m}^{3} ) c. ( 2 times 10^{9} k g / m^{3} ) D. ( 1 times 10^{17} k g / m^{3} ) | 12 |

472 | A nucleus ( X ) initially at rest, undergoes alpha decay according to the equation [ mathbf{9 2}^{boldsymbol{X}^{A}} rightarrow boldsymbol{Z}^{Y^{228}}+boldsymbol{alpha} ] Then, the values of ( A ) and ( Z ) are A .94,230 в. 232,90 c. 190,32 D. 230,94 | 12 |

473 | Assertion High-level waste and spent fuel from a nuclear power plant must be handled and stored with care. Reason Used fuel from a nuclear reactor is no longer efficient in creating electricity, because its fission process has slowed. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

474 | Obtain the exponential law of radioactive disintegration. Explain the decay curve. | 12 |

475 | A nuclear transformation is denoted by ( X(n, alpha)_{3}^{7} L i . ) Which of the following is the nucleus of element ( X ? ) ( mathbf{A} cdot frac{12}{6} C ) B . ( frac{10}{5} B ) ( c cdot_{5}^{9} B ) ( mathrm{D} cdot_{4}^{11} mathrm{Be} ) | 12 |

476 | If true enter 1 , else enter 0 . Atomic mass unit is also called Dalton(Da). | 12 |

477 | The nuclear fission chain reaction is initiated by the particle. A. Proton B. Neutron c. Electron D. Positron | 12 |

478 | ( 92^{38} U ) atom disintegrates to ( _{84}^{214} ) Po with a half life of ( 4.5 times 10^{9} y r s ) by emitting six alpha particles and ( n ) -electrons. Here ( n ) is: ( A cdot 6 ) B. 4 c. 10 D. 7 | 12 |

479 | The radioactive isotope of hydrogen contains 2 neutrons. A. True B. False | 12 |

480 | The nuclear reactor of the power plant must be shielded with ( _{-}-_{-}-_{-} ) walls. A. Leadd B. steel c. Both D. None | 12 |

481 | There are two radioactive substances ( A ) and B. Decay constant of B is two times that of A. Initially, both have equal number of nuclei. After ‘n’ half-lives of A, rates of disintegration of both are equal The value of ( ^{prime} boldsymbol{n}^{prime} ) is A . 1 B . 2 ( c cdot 4 ) D. all of these | 12 |

482 | Active mass of ( 5 g ) CaO is: A . 56 B. ( c .3 .5 ) D. 2 | 12 |

483 | Mark out the correct statement(s) This question has multiple correct options A. in alpha decay, the energy released is shared between alpha particle and daughter nucleus in the form of kinetic energy and share of alpha particle is more than that of the daughter nucleus B. in beta decay, the energy released is in the form of kinetic energy of beta particles C. in beta minus decay, the energy released is shared between electron and antineutrino D. in gamma decay, the energy released is in the form of energy carried by photons termed as gamma rays | 12 |

484 | There are ( _{text {一一一一一一 }} ) isotopes of oxygen A. 0 B. ( c cdot 2 ) D. | 12 |

485 | The process of increasing the percentage of fissionable ( U-235 ) in naturally occurring Uranium is called A. controlled fission B. artificial transmutation c. chemical process D. enrichment | 12 |

486 | When ( mathbf{U}^{238} ) nucleus originally at rest. decays by emitting an alpha particle having a speed ‘u’, the recoil speed of the residual nucleus is A ( cdot frac{4 mathrm{u}}{238} ) в. ( -frac{4 mathrm{u}}{234} ) c. ( frac{4 mathrm{u}}{234} ) D. ( -frac{4 mathrm{u}}{238} ) | 12 |

487 | If the activity of 108 Ag is 3 micro curie, the number of atoms present in it are ( lambda=0.005 mathrm{sec}^{-1} ) A. ( 2.2 times 10^{7} ) B. 2.2 ( times 10^{6} ) c. ( 2.2 times 10^{5} ) D. 2.2 times 10 ( ^{4} ) | 12 |

488 | Heavy water is used in nuclear reactor as A. Coolant B. Moderator c. Both coolant and moderator D. catalyst | 12 |

489 | Atomic number (Z) of a neutral atom and mass number (A) of an atom are equal to: (Here ( n= ) number of neutrons and ( p= ) number of protons) ( A cdot Z=n ) and ( A=n+p ) B. ( z=e ) and ( A=n+e ) c. ( z=p ) and ( A=n+p ) D. ( z=n ) and ( A=p+e ) | 12 |

490 | The value of ( A ) in the following reaction is ( _{4} mathrm{Be}^{9}+_{2} mathrm{He}^{4}=_{6} mathrm{C}^{A}+_{0} mathrm{n}^{1} ) A . 14 B. 10 c. 12 D. 16 | 12 |

491 | When the number of nucleons in nuclei increase, the binding energy per nucleon A. increases continuously with mass number B. decreases continuously with mass number c. remains constant with mass number D. first increases and then decreases with increase of mass number | 12 |

492 | Masses of neutron, proton and electron are ( 1.0087 cup, 1.0073 mathrm{u} ) and ( 0.0005 mathrm{u} ) respectively. If a neutron decays into a proton and an electron, the energy released would be about. A. ( 0.68 mathrm{MeV} ) B. 0.84 Mev c. ( 0.75 mathrm{MeV} ) D. ( 1.22 mathrm{MeV} ) | 12 |

493 | Fill in the blanks. The equation ( E=m c^{2} ) is derived by the scientist | 12 |

494 | ( 1 mathrm{kg} ) of iron (specific heat ( 120 mathrm{Cal} mathrm{kg}^{-1} mathrm{C} ) -1 ) is heated by ( 1000^{circ} mathrm{C} ). The increase in its mass is : A. zero B . ( 5.6 times 10^{-8} mathrm{kg} ) ( mathbf{c} cdot 5.6 times 10^{-16} mathrm{Kg} ) D. ( 5.6 times 10^{-12} mathrm{g} ) | 12 |

495 | In the fusion reaction ( _{1}^{2} boldsymbol{H} boldsymbol{e}+_{1}^{2} boldsymbol{H} rightarrow_{2}^{3} ) ( H e+_{0}^{1} n, ) the masses of deuteron, helium, and neutron expressed in amu are 2.015,3.017 and ( 1.009, ) respectively. If ( 1 k g ) of deuterium undergoes complete fusion, find the amount of total energy released. ( left(1 a m u=931.5 m e V / c^{2}right) ) ( mathbf{A} cdot approx 6.02 times 10^{13} J ) в. ( approx 5.6 times 10^{13} mathrm{J} ) | 12 |

496 | 27. The activity of a radioactive element decreases to one-thi of the original activity A, in a period of 9 years. After further lapse of 9 years, its activity will be (a) Ao | 12 |

497 | Reciprocal of radioactive decay constant is A. Half life period B. Whole life period c. Average life period D. Avagadro number | 12 |

498 | In the sun hydrogen is converted to A. Helium B. Uranium c. Polonium D. Radium | 12 |

499 | If the binding energy of the electron in a hydrogen atom is ( 13.6 e V ), the energy required to remove the electron from the first excited state of ( L i^{2+} ) is: A. 30.6 eV в. 13.6 eV c. ( 3.4 e V ) D. ( 122.4 mathrm{eV} ) | 12 |

500 | Results of calculations for four different designs of a fusion reactor using D-D reaction are given below. Which of these is most promising based on Lawson criterion? A. Deuteron density ( =2.0 times 10^{12} mathrm{cm}^{-3} ), confinement time ( =5.0 times 10^{-3} s ) B. Deuteron density ( =8.0 times 10^{14} mathrm{cm}^{-3} ), confinement time ( =9.0 times 10^{-1} s ) C. Deuteron density ( =4.0 times 10^{23} mathrm{cm}^{-3} ), confinement time ( =1.0 times 10^{-11} s ) D. Deuteron density ( =1.0 times 10^{24} mathrm{cm}^{-3} ), confinement time [ =4.0 times 10^{-12} s ] | 12 |

501 | ( 92 U^{238} ) changes to ( _{85} U^{210} ) by a series of ( alpha ) and ( beta ) decays. Find the number of ( alpha ) decays undergone (an integer) | 12 |

502 | ( X ) and ( Y ) are two radioactive isobars. Then the daughter nuclei formed after the emission of a ( beta ) particle from each of them are A. isosters B. isotones ( c . ) isobars D. isotopes | 12 |

503 | The decay constant of a radioactive sample is ( gamma ). Its half-life is ( T_{1 / 2} ) and mean life is ( boldsymbol{T} ). ( A cdot T_{1 / 2}=frac{1}{lambda}, T=frac{I n 2}{lambda} ) B・ ( T_{1 / 2}=frac{I n 2}{lambda}, T=frac{1}{lambda} ) ( mathbf{c} cdot_{T_{1 / 2}=lambda operatorname{In} 2, T}=frac{1}{lambda} ) D. ( T_{1 / 2}=frac{lambda}{I n 2}, T=frac{I n 2}{lambda} ) | 12 |

504 | Mass defect of 1 g gives energy equal to This question has multiple correct options ( mathbf{A} cdot 9 times 10^{13} J ) B ( .5 .625 times 10^{32} e V ) C ( .2 .15 times 10^{10} ) kcal D. ( 9 times 10^{6} ) ergs | 12 |

505 | ( 84 P_{0}^{210} ) originally at rest emits ( alpha ) particles of KE ‘K’ Find the KE of recoiling nucleus: A ( cdot frac{4}{214} K ) в. ( frac{4}{206} K ) c. ( frac{K}{206} ) D. ( frac{K}{214} K ) | 12 |

506 | Energy produced in nuclear power plants is example of: A. controlled nuclear fission B. uncontrolled nuclear fission c. controlled nuclear fusion D. uncontrolled nuclear fusion | 12 |

507 | The atomic mass of a hypothetical element ( X ) is 33.42 amu. ( A ) 27.22 ( g ) sample of ( X ) combines with 84.10 g of another hypothetical element Y to form the compound XY. The atomic mass of Y is: A. 68.50 amu B. 69.84 amu c. 103.3 amu D. 111.3 amu | 12 |

508 | Which symbols represent atoms that are isotopes? A. C-14 and N-14 B. 0-16 and 0-18 c. ( c-16 ) and ( N-14 ) D. Rn-222 and Ra-222 | 12 |

509 | The mass of ( U^{234} ) of radioactivity 1 curie is A . 3.7 ( times 10^{10} g ) B. 3.7 ( times 10^{-10} g ) c. ( 6.25 times 10^{-34} g ) D . 1.438 ( times 10^{-11} g ) | 12 |

510 | One a.m.u. or one ‘u’ is equal to: A ( cdot 1.6605389210^{-27} mathrm{kg} ) B . ( 1.6605389210^{-29} mathrm{kg} ) c. ( 1.2345765610^{-27} mathrm{kg} ) D . ( 1.2345765610^{-29} mathrm{kg} ) | 12 |

511 | The mean life time of a radionuclide, if its activity decreases by ( 4 % ) for every ( 1 h ) would be (product is non-radioactive, i.e., stable) A . ( 25 h ) в. ( 1.042 h ) ( c cdot 2 h ) D. ( 30 h ) | 12 |

512 | Hydrogen bomb is based on A. controlled chain reaction B. uncontrolled chain reaction c. nuclear fusion D. nuclear fission | 12 |

513 | A nucleus with atomic number ( z ) and neutron number N undergoes two decay processes. The result is a nucleus with atomic number Z-3 and neutron number N-1. Which decay processes took place? A . Two ( beta^{-} ) decays B. Two ( beta^{+} ) decays C. ( A n alpha-d e c a y ) and ( a beta^{-} ) decay D. An ( alpha- ) decay and a ( beta^{+} ) decay | 12 |

514 | How many half-lives does Carbon10 undergo in 2 minutes and 32 seconds? Given the half-life of Carbon- 10 is about 19 seconds. A. 8 half-lives B. 7 half-lives c. 6 half-lives D. 5 half-lives E. 4 half-lives | 12 |

515 | In a first order reaction the concentration of reactant decreases from ( 800 m o l / d m^{3} ) to ( 50 m o l / d m^{3} ) in ( 2 times 10^{2} s . ) The rate constant of reaction ( operatorname{in} s^{-1} ) is: ( A cdot 2 times 10^{4} ) B . ( 3.45 times 10^{-5} ) c. ( 1.386 times 10^{-2} ) D. ( 2 times 10^{-4} ) | 12 |

516 | Assertion (A) : Isotopes of an element can be separated by using a mass spectrometer Reason (R): Separation of isotopes is possible due to difference in electron number of isotopes. A. Both A and R are true and R is correct explanation of A B. Both A and R are true and R is not correct explanation of A C. A is true but R is false D. A is false but R is true | 12 |

517 | When two atoms of chlorine combine to form one molecule of chlorine gas, the energy of molecule: B. Equal to that of sepatate atommonm c. Lower than that of separate atoms D. None of the above | 12 |

518 | A radioactive sample has 5000 disintegration per minute initially and 1250 disintegration per minute after 5 seconds. Then the decay constant is A ( .0 .4 ln 2 ) B. ( 0.2 ln 2 ) c. ( 0.1 ln 2 ) D. ( 0.8 ln 2 ) | 12 |

519 | Which nuclide is formed as a result of this fission reaction? ( _{92}^{235} U+_{0}^{1} n rightarrow 3_{0}^{1} n+_{56}^{139} B a+ ) A ( cdot frac{96}{33} mathrm{Br} ) B. 96 36 c. 彎 ( R b ) ( b ) E ( cdot frac{90}{33} mathrm{Sr} ) | 12 |

520 | Fusion reaction takes place at high temperature because A. ( mathrm{KE} ) is high enough to overcome repulsion between nuclei B. Nuclei are most stable at this temperature C. Nuclei are unstable at this temperature D. None of the above | 12 |

521 | Determine the energy released during the fusion of ( _{1} H^{1} ) to form a ( _{2} H e^{4} ) nucleus, if the total mass of the products is ( 4.001506 u, ) mass of proton is ( 1.0078 u ) and mass of neutron is ( 1.00878 u ) ( mathbf{A} cdot 27.67 M e V ) в. ( 27.67 J ) c. ( 127.67 J ) D. 127.67 MeV | 12 |

522 | Y AM 31. A radioactive nucleus (initial mass number A and atomic number Z) emits three O-particles and two positrons. The ratio of the number of neutrons to that of protons in the final nucleus will be (b) 4-2-4 (a) 4724 (c) 4-Z-12 (a) 4z2=4 (AIEEE 2010) | 12 |

523 | Write down the sequence of radiations emitted in the following radioactive processes. ( z+2 boldsymbol{X}^{boldsymbol{A}} rightarrow_{z} boldsymbol{Y}^{boldsymbol{A}-mathbf{4}} rightarrow_{boldsymbol{z}+mathbf{1}} boldsymbol{Y}^{boldsymbol{A}-mathbf{4}} rightarrow_{boldsymbol{z}-mathbf{1}} ) ( boldsymbol{K}^{boldsymbol{A}-boldsymbol{8}} ) A. ( gamma-beta-alpha ) B . ( gamma-alpha-beta ) c. ( beta-gamma-alpha ) D. ( alpha-beta-alpha ) | 12 |

524 | Electron-positron pair can be created by ( gamma ) -rays. In this process the minimum energy of ( gamma ) -rays should be : A. ( 5.0 mathrm{MeV} ) в. ( 4.02 mathrm{MeV} ) c. ( 15.0 mathrm{MeV} ) D. ( 1.02 mathrm{MeV} ) | 12 |

525 | Mark out the correct statement(s) This question has multiple correct options ( A . ) in both fission and fusion processes, the mass of reactant nuclide is greater than the mass of product nuclide B. in fission process, BE per nucleon of reactant nuclide is less than the binding energy per nucleon of product nuclide C. in fusion process, BE per nucleon of reactant nuclide is less than the binding energy per nucleon of product nuclide D. in fusion process, BE per nucleon of reactant nuclide is greater than the binding energy per nucloen of product nuclide | 12 |

526 | During a nuclear fission reaction: This question has multiple correct options A. a heavy nucleus breaks in two or more fragment by itself B. a light nucleus bombarded by thermal neutrons breaks up C. a heavy nucleus bombarded by thermal neutrons breaks up D. two light nuclei combine to give a heavier nucleus and possibly other products | 12 |

527 | Mean life of a radioactive sample is 100 s. Then its half-life(in minutes) is. A. 0.693 B. ( c cdot 10^{-4} ) D. 1.155 | 12 |

528 | Which one moves with greatest speed: A . ( alpha ) -rays B. ( beta ) -rays c. ( gamma ) -rays D. cathode rays | 12 |

529 | Calculate the energy emitted by the sun in one second. Also estimate the mass of the sun that is converted to energy in one second. (Take solar constant as ( 1.4 times ) ( 10^{3} W m^{-2}, ) distance between the earth and the sun as ( 1.5 times 10^{11} m ) and the velocity of light as ( 3 times 10^{8} m S^{-1} ) ). | 12 |

530 | Assertion The atomic mass of potassium is 39 Reason An atom of potassium is 39 times heavier than ( frac{1}{12} ) th of the mass of carbon ( operatorname{atom}left(boldsymbol{C}^{12}right) ) Read the above assertion and reason and choose the correct option regarding ¡t. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

531 | ( ln beta ) decay. A. Atomic number decreased by one B. Mass number decreases by one C. Proton number remains the same D. Neutron number decreases by one | 12 |

532 | State the change in the form of a reaction A ( cdot frac{234}{92} A rightarrow_{888}^{232} B+frac{4}{2} H e ) ( e e ) B ( cdot frac{238}{92} A rightarrow_{90}^{234} B+_{2}^{4} H e ) C ( cdot frac{238}{911} mathrm{A} rightarrow_{839}^{234} mathrm{B}+_{2}^{4} mathrm{He} ) D ( cdot frac{234}{92} A rightarrow_{992}^{234} B+_{2}^{4} H e ) | 12 |

533 | 1 g of hydrogen is converted into 0.993 g of helium in a thermonuclear reaction. The energy released is : A ( cdot 63 times 10^{7} ) J В. ( 63 times 10^{10} ) 」 D. ( 63 times 10^{20} ) 」 | 12 |

534 | Which of the following elements are isotopes This question has multiple correct options A ( cdot c^{12} ) в. ( c^{13} ) ( c cdot c^{1} ) D. ( N^{14} ) | 12 |

535 | What are the value of ( a ) and ( b ) respectively in the reaction ( _{9}^{4} B e+ ) ( _{2}^{4} H e rightarrow_{b}^{a} X+_{0}^{1} n ) A .17,7 B. 7,11 ( c cdot 12,6 ) D. 6,12 | 12 |

536 | The activity of a radioactive sample is measured as 9750 count ( / ) min at ( t=0 ) and 975 count/min at ( t=5 ) min.The decay constant is nearly A. 0.922 min ( ^{-1} ) B. ( 0.691 mathrm{min}^{-1} ) c. ( 0.461 min ^{-1} ) D. 0.230 ( min ^{-1} ) | 12 |

537 | Calculate the energy released when an electron annihilates a positron. | 12 |

538 | Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion 5 billion years ago. The probability of decay during the next time is. A. Different for each nuclei B. Nuclei created in explosion decays first c. Nuclei created in the reactor decays first D. Independent of the time of creation | 12 |

539 | An element ( A ) decays into element ( C ) by the following two step processes: ( boldsymbol{A} longrightarrow_{2} boldsymbol{H} boldsymbol{e}^{boldsymbol{4}}+boldsymbol{B} ) ( boldsymbol{B} longrightarrow mathbf{2}left(_{-1} boldsymbol{e}^{0}right)+boldsymbol{C} ) Select pair for isobars from elements ( A, B ) and ( C ) | 12 |

540 | The heavier stable nuclei tend to have larger N/Z ratio because This question has multiple correct options A. A neutron is heavier than a proton B. A neutron is an unstable particle C. A neutron does not exert electric repulsion D. Coulomb forces have longer range compared to nuclear forces | 12 |

541 | ( alpha, beta ) and ( gamma ) radiations come out of a rodiactive substance A. when it is heated B. when put in atomic reactor c. spontaneously D. under pressure | 12 |

542 | When the reactor shuts down why does it require cooling? A. To cool the reactor from chain reaction B. To cool the reactor from fission reaction c. Both (1) and (2) D. None of these | 12 |

543 | What is radioactivity? Show that radioactive decay is exponential in nature. The half-life of a certain substance is 5 days. How many days does this substance take for ( 31 / 32^{t h} ) of the initial mass of disintegrate? | 12 |

544 | There is a stream of neutrons with a kinetic energy of 0.0327 eV. If the halflife of neutrons is 700 s, what fraction of neutrons will decay before they travel a distance of ( 10 mathrm{m} ? ) Given mass of neutron ( =1.676 times 10^{-27} k g ) | 12 |

545 | A nuclide ( A ) undergoes ( alpha ) decay and another nuclide ( B ) undergoes ( beta ) decay. Then This question has multiple correct options A. all the ( alpha ) -particles emitted by ( A ) will have almost the same speed B. the ( alpha ) -particles emitted by ( A ) may have widely different speeds C . all the ( beta ) -particles emitted b ( B ) will have almost the same speed D. the ( beta ) -particles emitted by ( B ) may have widely different speeds. | 12 |

546 | 40. The half-life of At is 100 us. The time taken for the radioactivity of a sample of At to decay to 1/16th of its initial value is (a) 400 us (b) 6.3 us (c) 40 us (d) 300 us | 12 |

547 | Isotopes of an element contain A. the same number of protons but different number of neutrons B. the same number of neutrons but different number of protons C . equal number of protons and electrons D. equal number of nucleons | 12 |

548 | An alpha particle ( left(^{4} H eright) ) has a mass 4.00300 amu. A proton has a mass ( mathbf{1 . 0 0 7 8 3} ) amu and a neutron has a mass ( mathbf{1 . 0 0 8 6 7} ) amu respectively. The binding energy of alpha estimated from these data is closest to: ( mathbf{A} cdot 27.9 mathrm{MeV} ) в. ( 22.3 mathrm{MeV} ) c. ( 35.0 mathrm{MeV} ) D. 20.4 MeV | 12 |

549 | The binding energies per nucleon for deuteron and helium are ( 1.1 mathrm{MeV} ) and 7 MeV respectively. Calculate the energy released when two deuterons fuse to form a helium nucleus. A. 23.6 MeV B. 25.8 MeV c. ( 19.2 mathrm{MeV} ) D. 28.8 MeV | 12 |

550 | The particle A is converted to C via following reactions then: ( boldsymbol{A} rightarrow boldsymbol{B}+_{2} boldsymbol{H} boldsymbol{e}^{boldsymbol{4}} ) ( boldsymbol{B} rightarrow boldsymbol{C}+boldsymbol{2}_{-1} boldsymbol{e}^{boldsymbol{0}} ) A. A and C are isobars B. ( A ) and ( C ) are isotopes C. ( A ) and ( B ) are isobars D. ( A ) and ( B ) are isotopes | 12 |

551 | Hydrogen atoms usually contain a single neutron. Deuterium and tritium are isotopes of hydrogen containing two and three neutrons, respectively. How many electrons orbit the tritium nucleus if the atom is electrically neutral? A. 0 B. ( c cdot 2 ) D. 3 | 12 |

552 | The fusion of light elements take place at about the temperatures of about ( mathbf{A} cdot 30^{circ} C ) B. ( 100^{circ} mathrm{C} ) c. ( 10,000^{circ} mathrm{C} ) D ( .2 times 10^{0} mathrm{C} ) | 12 |

553 | The probability of a radioactive nucleus to survive one mean life is ( frac{1}{e+x}, ) then ( x ) is | 12 |

554 | cosmic rays, solar radiation, naturally occurring radioactive elements are all sources of A. External background radiation B. Internal background radiation c. Radioactive radiation D. All of the above | 12 |

555 | The ionisation energy of 10 times ionized sodium atom is ( mathbf{A} cdot frac{13.6}{11} e V ) B. ( frac{13.6}{112} e V ) C ( .13 .6 times(11)^{2} e V ) D. ( 13.6 e V ) | 12 |

556 | Two separate monochromatic light beams ( A ) and ( B ) of the same intensity are falling normally on a unit area of a metallic surface. Their wavelengths are ( boldsymbol{lambda}_{A} ) and ( boldsymbol{lambda}_{B}, ) respectively. Assuming that all the incident light is used in ejecting the photoelectrons, the ratio of the number of photoelectrons from beam ( boldsymbol{A} ) to that from ( B ) is: A. ( frac{lambda_{A}}{lambda_{B}} ) в. ( frac{lambda_{B}}{lambda_{A}} ) ( ^{c}left(frac{lambda_{B}}{lambda_{A}}right)^{2} ) ( ^{mathrm{D}}left(frac{lambda_{A}}{lambda_{B}}right)^{2} ) | 12 |

557 | What is the atomic mass (u) of Sodium ( ? ) A . 22 B. 23 c. 23.5 D. 24 | 12 |

558 | A radioactive sample has ( 2.0 times 10^{20} ) active nuclei at a certain instant of time. Then the the number of samples in the same active state after three half- lives is A ( .2 .5 times 10^{15} ) B. ( 2.5 times 10^{21} ) c. ( 2.5 times 10^{19} ) D. ( 2.5 times 10^{16} ) | 12 |

559 | Fill in the blank: In the carbon cycle, from which stars, hotter than the Sun, obtain their energy, the ( _{6} C^{12} ) isotope A. splits up into three alpha particles B. fuses with another ( _{6} C^{12} ) nucleus to form ( _{12} M g^{2} ) c. is completely converted into energy D. is regenerated at the end of the cycle | 12 |

560 | Hydroelectric power plants are more ecofriendly than thermal power plants. Justify this statement. | 12 |

561 | The nuclear reaction that takes place in a nuclear reactor is a/an A. controlled fission reaction B. uncontrolled fission reaction c. nuclear fusion reaction D. none of the above | 12 |

562 | The critical mass of a fissionable material is A. ( 0.1 mathrm{kg} ) B. the minimum mass needed for chain reaction C. the rest mass equivalent to 1020 joules D. ( 0.5 mathrm{kg} ) | 12 |

563 | An atom initially at an energy level ( boldsymbol{E}= ) ( -6.52 e V . ) It absorbs a photon of wavelenght ( 860 n m . ) What is the interna energy of atom after absorbing photon. A . ( 5.08 e V ) B. ( 1.44 e V ) c. ( -1.44 e V ) D. ( -5.08 e V ) | 12 |

564 | What are isotopes? Give an example also. | 12 |

565 | The radio nuclide ( ^{11} boldsymbol{C} ) decays according to ( _{6}^{11} C rightarrow_{5}^{11} B+e^{+}+nu: T_{1 / 2}= ) 20.3 min The maximum energy of the emitted positron is ( 0.960 mathrm{MeV} ) Given the mass values: ( boldsymbol{m}left(_{6}^{11} boldsymbol{C}right)=mathbf{1 1 . 0 1 1 4 3 4} boldsymbol{u} ) and ( boldsymbol{m}left(_{6}^{11} boldsymbol{B}right)=mathbf{1 1 . 0 0 9 3 0 5} boldsymbol{u} ) Calculate ( Q ) and compare it with the maximum energy of the positron emitted. | 12 |

566 | The number of neutrons accompanying the formation of ( _{54}^{139} X e ) and ( _{38}^{94} S r ) from the absorption of a slow neutron by ( _{92}^{235} U ) followed by nuclear fission is: ( mathbf{A} cdot mathbf{0} ) B . 2 c. 1 D. 3 | 12 |

567 | If all the atoms of ( 1 k g ) of deuterium undergo fusion approximately how much energy could be released? A ( .7 .87 times 10^{13} mathrm{J} ) B . ( 9 times 10^{11} ) calories c. ( 9 times 10^{12} k W h ) D. ( 79 times 10^{7} k W h ) | 12 |

568 | To obtain an isotope of a given radioactive atom, the atom must emit A. one alpha and one beta particle B. one alpha and two beta particle c. two alpha and two beta particle D. three alpha and four beta particle | 12 |

569 | If ( 1 mathrm{mg} ) of ( U^{235} ) is completely annihilated, the energy liberated is ( begin{array}{ll}text { A. } & 9 times 10^{10} Jend{array} ) в. ( quad 9 times 10^{19} J ) ( begin{array}{ll}text { с. } & 9 times 10^{18} Jend{array} ) D. ( quad 9 times 10^{17} J ) | 12 |

570 | The mass of ( _{2} H e^{4} ) nnucleus is 0.03 amu less than the sum of the masses of 2 protons and 2 neutrons. What is the binding energy per nucleon? | 12 |

571 | 2. A radioactive sample has half-life of 5 years. Probability of decay in 10 years will be (a) 100% (b) 75% (c) 50% (d) 25% | 12 |

572 | What is Chain Reaction? A. Particles released by splitting of atom strikes other uranium atoms and split them. B. Particles released by expanding of atom strikes other uranium atoms and split them C. Particles released by contracting of atom strikes other uranium atoms and split them D. None | 12 |

573 | When an atom undergoes ( beta^{+} ) decay A. a neutron changes into a proton B. a proton changes into a neutron C . a neutron changes into an antiproton D. a proton changes into an antineutron | 12 |

574 | Which of the following is true regarding the working process of weapon? This question has multiple correct options A. Energy is released when those neutrons split off from the nucleus B. splitting the nuclei in the same way, releasing more energy and more neutrons. C. The splitting of atomic nuclei releases enormous energy D. None of the above | 12 |

575 | The fission of a heavy nucleus gives, in general, two smaller nuclei, two or three neutrons, some ( beta- ) particles, and some ( gamma- ) radiation. It is always true that the nuclei produced A. have a total rest-mass that is greater than that of the original nucleus B. have large kinetic energies that carry off the greater part of the energy released c. travel in exactly opposite directions D. have neutron-to-proton ratios that are too low for stability E. have identical neutron-to | 12 |

576 | Carbon has ( _{text {十一一一一一一一一一 }} ) isotopes. ( A cdot 1(text { one }) ) B. 2 (two) c. 3 (three) D. 4 (four) | 12 |

577 | After five half lives, percentage of original radioactive atoms left is: A . 1% B. 0.3% c. ( 3.125 % ) D. 0.2% | 12 |

578 | The probability that a certain radioactive atom would get distance in a time equal to the mean life of the radioactive sample is A . 0.37 B. 0.63 ( c .0 .50 ) D. 0.67 | 12 |

579 | Which of the following is correct? A. There are 78 neutrons in ( 78 P t^{192} ) B ( cdot_{84} P o^{214} rightarrow_{82} P b^{210}+beta ) ( mathbf{c} cdot_{92} U^{238} rightarrow_{90} T h^{234}+_{2} H e^{4} ) D・ ( _{90} T h^{234} rightarrow_{91} P a^{234}+_{2} H e^{4} ) | 12 |

580 | Direction for Questions 29 and 30: These questions are based on the following paragraph. A nucleus of mass M + Am is at rest and decays into two daughter nuclei of equal masses M/2 each. The speed of light is c. (AIEEE 2010) 29. The binding energy per nucleon for the parent nucleus is E, and that for the daughter nuclei is E2. Then (a) E2 = 2E (b) E > E2 (c) Ez > E (d) E1 = 2E2 | 12 |

581 | Calculate the mass loss in the following: ( _{1}^{2} boldsymbol{H}+_{1}^{3} boldsymbol{H} longrightarrow_{2}^{4} boldsymbol{H} boldsymbol{e}+_{0}^{1} boldsymbol{n} ) Given the masses: ( _{1}^{2} H=2.014 ) amu, ( _{1}^{3} boldsymbol{H}=mathbf{3 . 0 1 6} boldsymbol{a m u} ;_{2}^{4} boldsymbol{H e}=mathbf{4 . 0 0 4} boldsymbol{a m u} ) ( mathbf{0}_{mathbf{n}}=mathbf{1 . 0 0 8} ) amu. ( mathbf{A} cdot 0.018 a m u ) B. 0.18 amu c. 0.0018 amu D. 1.8 amu E . 18 amu | 12 |

582 | The binding energy of a nucleus is equivalent to A. the mass of nucleus B. the mass of proton c. the mass of neutron D. the mass defect of nucleus | 12 |

583 | The binding energy per nucleon of deuteron ( left(_{1} H^{2}right) ) and helium ( left(_{2} H e^{4}right) ) are 1.1 ( M e V ) and ( 7.0 mathrm{MeV} ), respectively. The energy released when two deuterons fuse to form a helium nucleus is A. ( 36.2 mathrm{MeV} ) B. 23.6 MeV c. ( 47.2 mathrm{MeV} ) D. ( 11.8 mathrm{MeV} ) E. ( 9.31 mathrm{MeV} ) | 12 |

584 | In a sample of radioactive material, what percentage of the initial number of active nuclei will decay during one mean life? A . ( 37 % ) B. ( 50 % ) ( c cdot 63 % ) D. ( 69 % ) | 12 |

585 | Assertion Molar mass of ( C a ) is not always 40 gm. Reason Average molar mass of ( C a ) is 40 gm and is calculated by abundance percentage of all isoptopes of ( boldsymbol{C} boldsymbol{a} ) | 12 |

586 | The binding energy per nucleon of ( ^{16} mathrm{O} ) is ( 7.97 M e V ) and that of ( 17 O ) is ( 7.75 M e V ) The energy in MeV required to remove a neutron from ( ^{17} ) O is: A . 3.52 в. 3.64 c. 4.23 D. 7.86 E . 1.68 | 12 |

587 | The reactor which produces power due to fission by fast neutrons and regenerates more fissionable material than it consumes is A. Thermal reactor B. Breeder reactor c. Both the above D. None | 12 |

588 | Nuclei containing different number of protons but same number of neutrons are called A. Isoclines B. isobars c. isotones D. isotopes | 12 |

589 | The phenomenon of nuclear fission can be carried out both in a controlled and in an uncontrolled way. Out of the following, the correct statements vis- avis these phenomena are This question has multiple correct options A. the fission energy released per reaction is much more than conventional nuclear reactions and one of the products of the reaction is that very particle which initiates the reaction B. it is the “surface to volume” ratio of the sample of nuclear fuel used which determines whether or not the reaction would sustain itself as a “chain reaction” c. the “control rods” in a nuclear reactor must be made of material that absorbs neutrons effectively D. the energy released per fission as well as energy released per unit mass of the fuel in nuclear fission are both greater than the corresponding quantities for nuclear fusion | 12 |

590 | A radioactive material decays by simultaneous emission of two particles with half-lives 1620 yr and 810 yr respectively. The time in years after which one-fourth of material remains, is A . 1080 yr B. 2340 yr c. 4860 yr D. 3240 yr | 12 |

591 | Mass number is denoted by: ( A cdot D ) B. s ( c cdot A ) D. z | 12 |

592 | Obtain an expression for the number of radioactive nuclei present at any instant in terms of the decay constant and initial number of nuclei | 12 |

593 | How many nuclear power plants does India have in ( 2018 ? ) ( A cdot 2 ) B. 3 c. 7 D. None of these | 12 |

594 | The energy equivalent to ( 1 k g ) of matter in (in Joule) ( mathbf{A} cdot 10^{17} ) B. ( 19^{20} ) ( c cdot 10^{11} ) D. ( 10^{14} ) | 12 |

595 | If the masses of deuterium and that of helium are 2.0140 amu and 4.0026 amu, respectively and that ( 22.4 mathrm{MeV} ) energy is liberated in the reaction ( _{6}^{3} L i+_{1}^{2} H rightarrow_{2}^{4} H+_{2}^{4} H e, ) has the mass of ( _{3}^{6} L i ) is A . 6.015 amu B. 6.068 amu c. 5.980 amu D. 6.00 amu | 12 |

596 | An example of nuclear fusion reaction is : A ( cdot frac{2033}{90} mathrm{Th}+frac{1}{0} mathrm{n} rightarrow frac{23^{3} mathrm{Th}}{ } ) B ( cdot frac{27}{13} mathrm{AI}+frac{4}{2} mathrm{He} rightarrow frac{30}{15} mathrm{P}+frac{1}{0} mathrm{n} ) ( mathbf{c} cdot_{2}^{3} mathrm{He}+_{2}^{3} mathrm{He} rightarrow_{2}^{4} mathrm{He}+2_{1}^{1} mathrm{H} ) D ( cdot frac{239}{92} mathrm{U} rightarrow_{93}^{239} mathrm{Np}+_{-1}^{0} mathrm{e} ) | 12 |

597 | Which table correctly matches the numbered equations below with the correct nuclear process? 1) ( frac{1}{1} boldsymbol{H}+_{1}^{2} boldsymbol{H} rightarrow_{2}^{3} boldsymbol{H} boldsymbol{e}+boldsymbol{gamma} ) 2) ( 241 A m rightarrow_{93}^{237} N p+_{2}^{4} H e ) ( 95^{1} A m^{2} e^{23} ) 3) ( _{92}^{235} boldsymbol{U}+_{0}^{1} boldsymbol{n} rightarrow_{56}^{139} boldsymbol{B} boldsymbol{a}+_{36}^{94} boldsymbol{K} boldsymbol{r}+boldsymbol{3}_{0}^{1} boldsymbol{n} ) 4) ( begin{array}{l}138 \ 53end{array} boldsymbol{I} rightarrow_{54}^{138} boldsymbol{X} boldsymbol{e}+_{-1}^{0} boldsymbol{e}+overline{boldsymbol{v}} ) A. 1 alpha decay 2 nuclear fission 3 beta decay 4 nuclear fusion B. 1 nuclear fission 2 alpha decay 3 nuclear fusion 4 beta decay c. 1 nuclear fusion 2 alpha decay 3 nuclear fission 4 beta decay D. 1 Nuclear fusion 2 beta decay 3nuclear fission 4 alpha decay E. 1 beta decay 2alpha decay ear fusion ear fission | 12 |

598 | Assertion (A): The half life of a radioactive isotope is equal to ( frac{mathbf{0 . 6 9 3}}{boldsymbol{lambda}} ) Reason (R): Radioactivity is a first order reaction The correct answer is A. Both A and R are true and R is correct explanation of A B. Both A and R are true and R is not the correct explanation of C. A is true but R is false D. A is false but R is true | 12 |

599 | Find whether ( alpha ) – decay or any of the ( beta- ) decay are allowed for ( _{89}^{226} A c ) Given masses are: ( Mleft(_{89}^{226} A cright)=226.028356 a m u ) ( Mleft(_{87}^{222} F rright)=222.017415 a m u ) ( Mleft(_{90}^{226} T hright)=226.017388 a m u ) ( Mleft(_{88}^{226} R aright)=226.025406 a m u ) ( Mleft(_{2}^{4} H eright)=4.002603 a m u ) | 12 |

600 | The binding energies per nucleon of deutreron ( left(_{1} H^{2}right) ) and helium ( left(_{2} H e^{4}right) ) atoms are ( 1.1 mathrm{MeV} ) and ( 7 mathrm{MeV} ). If two deuteron atoms react to form a single helium atom, then the energy released is A. ( 13.9 mathrm{MeV} ) в. ( 26.9 mathrm{MeV} ) c . ( 23.6 mathrm{MeV} ) D. ( 19.2 mathrm{MeV} ) | 12 |

601 | Slow neutrons can bring about the fission of : A ( cdot 92left[U^{235}right. ) В. ( s_{2} U^{238} ) c. ( _{82} P b^{207} ) D・ ( 88 U^{226} ) | 12 |

602 | For which of the following, number of neutrons and protons is same? A. Chlorine B. Deuterium c. Protium D. Fluorine | 12 |

603 | Which of the following relations hold for units of activity? A. ( 1 B q=1 ) decay ( / s ) В . ( 1 C l=3.7 times 10^{10} B q^{4} ) C ( .1 R d=10^{6} B q ) D. All of the above | 12 |

604 | Among the following reactions, the impossible one is : A ( cdot^{2} H e_{4}+^{4} B e_{9} longrightarrow^{0} n_{1}+^{6} C_{12} ) B. ( ^{2} mathrm{He}_{4}+^{7} mathrm{N}_{14} longrightarrow^{1} mathrm{H}_{1}+^{8} mathrm{O}_{17} ) ( mathbf{c} cdot 4left(^{1} H_{1}right) rightarrow^{2} H e_{4}+^{2}left(^{-1} e_{0}right) ) D. ( ^{3} L i_{7}+^{1} H_{1} longrightarrow^{4} B e_{8} ) | 12 |

605 | Parto of the uranium decay series is shown ( 92^{2}-90 T h^{234} rightarrow 91 P a^{234} rightarrow ) ( 92 U^{234} rightarrow_{90} T h^{230} rightarrow_{88} R a^{226} ) How many pairs of isotopes are there in the above series: A ( . ) B. 2 ( c cdot 3 ) D. | 12 |

606 | 33. The probability of survival of a radioactive nucleus for one mean life is (b) 1 – – (d) 1 – In 2 | 12 |

607 | 46. Assuming that about 200 MeV of energy is released per fission of ,2U23s nuclei, then the mass of U235 consumed per day in a fission reactor of power 1 megawatt will be approximately (a) 100g (b) lg (c) 100 g (d) 10,000 g | 12 |

608 | The heavy atom of hydrogen has neutrons. A. 0 B. ( c cdot 2 ) ( D ) | 12 |

609 | One milligram of matter is converted into energy. The energy released will be ( mathbf{A} cdot 9 times 10^{6} J ) B ( .9 times 10^{8} J ) c. ( 9 times 10^{10} J ) D. ( 9 times 10^{12} J ) | 12 |

610 | Which row describes the nature of ( alpha ) – particles and of ( gamma- ) rays A. ( alpha ) – particles : helium nuclei ; rays – electromagnetic radiation B. ( alpha ) – particles : helium nuclei ; gamma rays – electrons c. ( alpha ) – particles: protons; ( gamma ) rays – electromagnetic radiation D. ( alpha ) – particles: protons; ( gamma ) rays – electrons | 12 |

611 | Consider an ( alpha ) -particle just in contact with a ( _{92}^{238} mathrm{U} ) nucleus. The Coulombic repulsion energy (i.e, the height of the Coulombic barrier between ( ^{238} mathrm{U} ) and alpha particle) assuming that the distance between them is equal to the sum of their radii is ( mathbf{A} cdot 16.35 M e V ) в. ( 46.66 mathrm{MeV} ) c. 22.24 MeV D. 26.14 ( M e V ) | 12 |

612 | If the decay constant of radium is ( 4.28 times 10^{-4} ) per year, then its half life will be approximately be A. 1240 years B. 1620 years c. 2000 years D. 2260 years | 12 |

613 | Which of the following term means the difference between the mass of the nucleus and the sum of each individual nucleon? A. mass defect B. nucleon difference c. nucleon defect D. mass difference E. nuclear difference | 12 |

614 | The radioactive decay rate of a radioactive element is found to be ( 10^{3} ) disintegrations / second at a certain time. If the half life of the element is one second, the decay rate after one second is x disintegrations per sec and after three seconds is y disintegrations per sec. Then ( y / x= ) | 12 |

615 | It is proposed to use the nuclear fusion reaction ( _{1} H^{2}+_{1} H^{2} longrightarrow H e^{4} ) in a nuclear reactor with an electrical power rating of ( 200 M W . ) If the energy form the above reaction is used with 25 percent efficiency in the reactor, how many grams of deuterium fuel will be needed per day? (The masses of ( _{1} boldsymbol{H}^{2} ) and ( _{2} H e^{4} ) are ( 2.0141 a m u ) and 4.0026 amu respectively.) | 12 |

616 | In a nuclear reactor, what is the function of a moderator? | 12 |

617 | The present day abundances of the isotopes ( bigcup^{238} ) and ( U^{235} ) are in the ratio of ( 128: 1 . ) They have half lives of ( 4.5 times ) ( 10^{9} ) years and ( 7 times 10^{8} ) years respectively and assume that the equal amount of each isotope existed at the time of formation of the earth. If age of earth is ( frac{49 X}{76} times 10^{9} ) years, then calculate ( X ) | 12 |

618 | In each fission of ( _{92}^{235} mathrm{U}, 200 mathrm{MeV} ) energy is released. How many fissions must occur per second to produce power of ( mathbf{1} k W ? ) A ( cdot 1.25 times 10^{18} ) В. ( 3.125 times 10^{13} ) C ( .3 .2 times 10^{18} ) D. ( 1.25 times 10^{13} ) | 12 |

619 | Consider the following statements: ( A: p-p, p-n, n-n ) forces between nucleons are not equal and charge dependent B: In nuclear reactor the fission reaction will be in accelerating state if the value of neutron reproduction factor ( k>1 ) A. Both A and B are correct B. Both A and B are wrongg C. A is wrong and B is correct D. A is correct and B is wrong | 12 |

620 | 31. The half-life of a certain radioactive isotope is 32 h. What fraction of a sample would remain after 16 h? (a) 0.25 (b) 0.71 (c) 0.29 (d) 0.75 | 12 |

621 | A student wrote the relation for one unified atomic mass unit (u) as ( 1 u= ) ( 931.5 M e V . ) What is the correct relation? A. ( 1 u times c=931.5 ) MeV В . ( 1 u times c^{2}=931.5 mathrm{MeV} ) c. ( frac{1 u}{c^{2}}=931.5 mathrm{MeV} ) D. ( (1 u)^{2} times c=931.5 mathrm{MeV} ) | 12 |

622 | The activity of a radioactive element decreases to one-third of the origina activity ( I_{0} ) in a period of nine years. After a further lapse of nine years, its activity will be A ( cdot I_{0} ) B . ( (2 / 3) I_{0} ) C ( cdotleft(I_{0} / 9right) ) D・ ( left(I_{0} / 6right) ) | 12 |

623 | A radioactive nucleus can decay by two different processes. The mean value period for the first process is ( t_{1} ) and that for the second process is ( t_{2} ). The effective mean value period for the two processes is A ( cdot frac{t_{1}+t_{2}}{2} ) B . ( t_{1}+t_{2} ) c. ( sqrt{t_{1} t_{2}} ) D. ( frac{t_{1} t_{2}}{t_{1}+t_{2}} ) | 12 |

624 | Assertion The binding energy per nucleon, for nuclei with the atomic mass number ( A>100, ) decreases with ( A ) Reason The nuclear forces are weak for heavier nuclei. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

625 | At present, electricity production is not taking place using A. nuclear fission B. nuclear fusion c. burning of coil D. it is being produced using all the above methods | 12 |

626 | Nuclear fusion is a A. thermonuclear reaction B. thermochemical reaction c. electrochemical reaction D. none of these | 12 |

627 | The nucleus ( _{92} mathrm{X}^{234} ) emits ( 3 alpha ) -particles and then one ( beta ) -particle. The end product will be A ( cdot 84 mathrm{Y}^{222} ) В. ( 87 mathrm{Y}^{228} ) ( mathbf{c} cdot_{84} mathbf{Y}^{228} ) D・ ( _{87} mathrm{Y}^{222} ) | 12 |

628 | The number ( N_{Y} ) of nuclei of ( Y ) at ( t= ) ( T_{1 / 2} ) is A. ( K frac{l n 2}{lambda}+frac{3}{2}left(frac{K-lambda N_{0}}{lambda}right) ) в. ( K frac{l n 2}{lambda}+frac{1}{2}left(frac{K-lambda N_{0}}{lambda}right) ) c. ( quad K frac{l n 2}{lambda}-frac{1}{2}left(frac{K-lambda N_{0}}{lambda}right) ) D. ( K frac{ln 2}{lambda}-2left(frac{K-lambda N_{0}}{lambda}right) ) | 12 |

629 | Atomic mass of ( _{6}^{13} C ) is 13.00335 amu and its mass number is ( 13.0 . ) If amu ( = ) ( 931 mathrm{MeV}, ) the binding energy of the neutrons present in the nucleus is A. ( 0.24 mathrm{MeV} ) B . ( 1.44 mathrm{MeV} ) c. ( 1.68 mathrm{MeV} ) D. 3.12 Mev | 12 |

630 | According to Einstein’s theory of relativity, mass can be converted into energy and vice-versa. The lightest elementary particles, taken to be the electron, has a mass equivalent to ( 0.51 M e V ) of energy. Then we can say that This question has multiple correct options A. The minimum amount of energy available through conversion of mass into energy is ( 1.02 mathrm{MeV} ) B. The least energy of a ( gamma- )ray photon that can be converted into mass is ( 1.02 mathrm{MeV} ) c. Whereas the minimum energy released by conversion of mass into energy is ( 1.02 mathrm{MeV} ), it is only a ( gamma-mathrm{ray} ) photon of energy ( 0.51 mathrm{MeV} ) and above that can be converted into mass D. Whereas the minimum energy released by conversion of mass into energy is ( 0.51 mathrm{MeV} ), it is only a ( gamma-mathrm{ray} ) photon of energy ( 1.02 mathrm{MeV} ) and above that can be converted into mass | 12 |

631 | Which of the following is/are example(s) of isobars? A. ( 11 . N a^{23} ) and ( 12 mathrm{Mg}^{24} ) ( ^{4} ) B . ( _{19} K^{39} ) and ( _{20} A r^{40} ) ( mathbf{c} cdot_{18} A r^{40} ) and ( _{20} C a^{40} ) D・ ( _{17} C l^{35} ) and ( _{17} C l^{37} ) | 12 |

632 | The principle behind the working of an atom bomb is: A. Nuclear fussion B. Nuclear fission c. Radioactivity D. None of these | 12 |

633 | A heavy nucleus ( X ) of mass number 240 and binding energy per nucleon ( 7.6 M e ) is split into two fragment ( Y ) and ( Z ) of mass numbers 110 and ( 130 . ) The binding energy per nucleon in ( Y ) and ( Z ) is ( 8.5 M e V ) per nucleon. Calculate the energy ( Q ) released per fission in ( M e V ) | 12 |

634 | A proton and a neutron are both shot at ( 100 m s^{-1} ) towards a ( frac{12}{6} C ) nucleus. Which particle, if either, is more likely to be absorbed by the nucleus? A. The proton B. The neutron C. Both particles are about equally likely to be absorbedd D. Neither particle will be absorbed | 12 |

635 | Function of moderator in a reactor is to A. slow down neutrons B. absorb neutrons c. speed up neutrons D. catalyse neutrons | 12 |

636 | Fill up the blanks. The particle of the nucleus that undergoes change during beta decay is | 12 |

637 | If a nuclues ( z^{A} ) emits ( 9 alpha ) and ( 5 beta ) particles, then the ratio of the total protons and neutrons in the final nucles is A ( cdot frac{(Z-13)}{(A-36)} ) в. ( frac{(Z-13)}{(A-Z-13)} ) c. ( frac{(Z-18)}{(A-36)} ) D. ( frac{(Z-13)}{(A-Z-23)} ) | 12 |

638 | Radiations from a nuclear power plant is harmful to: A. environment B. human civilization c. wildlife D. all of the above | 12 |

639 | A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half life of the source is: A. 80 min B. 120 min ( c .20 ) min D. 30 min | 12 |

640 | State whether the given statement is True or False : Nuclear power plants as compared to other plants can generate huge amount of electricity. | 12 |

641 | The ( t_{1 / 2} ) of a radioactive substance is 100sec. Its decay constant is: A ( cdot 6.93 times 10^{-3} mathrm{sec}^{-1} ) B. ( 6.93 times 10^{-2} ) sec ( ^{-1} ) D. ( 6.93 times 10^{-4} s e c^{-1} ) | 12 |

642 | The coolant used in the nuclear reactor is A . Liquid sodium B. Cadmium c. Deuterium D. Liquid hydrogen | 12 |

643 | Atom bomb consists of pieces of ( ^{92} U_{235} ) and a source of A. Proton B. Neutron c. Meson D. Electron | 12 |

644 | Write the principle behind the Hydrogen bomb. | 12 |

645 | Which one of them is a radioisotope? A. Cobalt-60 B. Carbon-12 c. carbon-14 D. None of the above | 12 |

646 | ( 2 g m ) of radio active element undergoes ( 3.7 times 10^{8} ) disintegrations per second. Its curie value is A ( .2 g ) в. ( 0.02 g ) ( c .200 g ) D. 3700g | 12 |

647 | Which symbol replaces the unit of atomic mass, amu? ( A ) B. A ( c . ) м ( D ) | 12 |

648 | Under certain circumstances, a nucleus can decay by emitting a particle more massive than an ( alpha ) -particle. Consider the following decay processes: ( 223 R a rightarrow frac{209}{82} P b+frac{14}{6} C ) 88 ( 223 R a rightarrow 219 R n+4 H e ) 88 Calculate the ( Q ) -values for these decays and determine that both are energetically allowed. | 12 |

649 | The half life, ( T ), of a substance is related to the decay constant by the equation ( A cdot T=frac{1}{lambda} ) в. ( frac{1}{0.693 lambda} ) c. ( frac{0.693}{lambda} ) D. ( frac{2.303}{lambda} ) | 12 |

650 | Ratio of initial active nuclei of the two different samples is 2 ratio 3 . Their half lives are 1 and 2 respectively. Ratio of active nuclei at the end of 6 hours will be A . 1: 1 B. 1: 12 c. 4: 3 D. 3: 4 | 12 |

651 | A nucleus ( _{Z}^{A} X ) has mass represented by ( boldsymbol{m}(boldsymbol{A}, boldsymbol{Z}) . ) If ( boldsymbol{m}_{boldsymbol{p}} ) and ( boldsymbol{m}_{boldsymbol{n}} ) denote the mass of proton and neutron respectively and BE the binding energy(in MeV) then. A ( cdot B E=left[mleft(A_{1} Zright)-Z m_{p}-(A-Z) m_{n}right] C^{2} ) B . ( B E=left[Z m_{p}+(A-Z) m_{n}-m(A, Z)right] C^{2} ) C ( . B E=left[Z m_{p}+A m_{n}-m(A, Z)right] C^{2} ) D. ( B E=mleft(A_{1} Zright)-Z m_{p}-(A-Z) m_{N} ) | 12 |

652 | In nuclear fusion, ( 1 g m ) hydrogen is converted into ( 0.993 g m ) Helium in one hour. If the efficiency of the generator is ( 5 %, ) the energy obtained in ( K W h ) is: ( mathbf{A} cdot 8.75 times 10^{3} ) B . ( 4.75 times 10^{3} ) c. ( 5.75 times 10^{3} ) D. ( 3.73 times 10^{3} ) | 12 |

653 | A proton exerts a force on a proton which is This question has multiple correct options A. gravitational B. electromagnetic c. nuclear D. weak | 12 |

654 | Out of the following which has no charge? A. ( alpha ) -rays B. ( beta ) -rays c. ( gamma ) -rays D. cathode rays | 12 |

655 | Initially 480 particles per minute are being emitted by a radioactive substance. This number reduces to 240 after 2 hours. The number of particles being emitted per minute after next 4 hour will be A . 0 B. 60 c. 80 D. 120 | 12 |

656 | The process by which the percentage of ( U-235^{prime} ) in ( U-238 ) is increased, is called A . fission B. fusion c. chain reaction D. enrichment | 12 |

657 | The binding energy of an electron in the ground state of ( boldsymbol{H} boldsymbol{e} ) atom is ( boldsymbol{E}_{mathbf{0}}= ) 24.6e ( V ). The energy required to remove both the electrons from the atom is A . ( 24.6 e V ) в. ( 79.0 e V ) c. ( 54.4 e V ) D. None of these | 12 |

658 | ( ^{23} N a ) is the more stable isotope of ( N a ) By which process ( _{11}^{24} N a ) can undergo radioactive decay? ( mathbf{A} cdot beta^{-}-e m i s s i o n ) B. ( alpha ) – emission c. ( beta^{+}- ) emission D. None of these | 12 |

659 | Assertion In a decay process of a nucleus, the mass of products is less than that of the parent. Reason The rest mass energy of the products must be less than that of the parent A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

660 | The binding energies per nucleon for a deuteron and an ( alpha ) -particle are ( x_{1} ) and ( x_{2} ) respectively.What will be the energy Q released in the reaction ( _{1} boldsymbol{H}^{2}+_{1} ) ( boldsymbol{H}^{2}+rightarrow_{2} boldsymbol{H} boldsymbol{e}^{4}+boldsymbol{Q} ) ( mathbf{A} cdot 4left(x_{1}+x_{2}right) ) B . ( 4left(x_{2}-x_{1}right) ) c. ( 2left(x_{1}+x_{2}right) ) D ( cdot 2left(x_{2}-x_{1}right) ) | 12 |

661 | The rays produced in the above experiment consist of A. protons B. neutrons C. positrons D. neutrinos | 12 |

662 | A neutron breaks into a proton and an electron. Calculate the energy produced in this reaction is MeV. Mass of an electron ( =9 times 10^{-31} k g, ) mass of proton ( =1.6725 times 10^{-27} k g, ) mass of neutron ( =1.6747 times 10^{-27} k g, ) and speed of light ( =3 times 10^{8} m s^{-1} ) | 12 |

663 | A nucleus ( _{11}^{24} N a ) is ( beta ) -radioactive. What general name is given to the product nucleus with respect of ( _{11}^{24} ) Na? A . isotope B. isonucleus c. isobar D. isoelectron | 12 |

664 | A nuclear transformation is denoted by ( X(n, alpha)_{3}^{7} L i . ) Which of the following is the nucleus of element ( boldsymbol{X} ) ? A ( cdot^{12} C_{6} ) В ( cdot frac{10}{5} B ) ( c cdot_{5}^{9} B ) ( mathrm{D} cdot_{4}^{11} mathrm{Be} ) | 12 |

665 | 15. A nuclear transformation is denoted by X (n, a) Li. Which of the following is the nucleus of element X? (a) “Be (b) B (c) B (d) 12C6 (AIEEE 2005) | 12 |

666 | Consider a sample of a pure beta-active material. Choose the correct one of the following. A. All the beta particles emitted have the same energy B. The beta particles originally exist inside the nucleus and are ejected at the time of beta decay C. The antineutrino emitted in a beta decay has zero mass and hence, zero momentum D. The active nucleus changes to one of its isobars after the decay | 12 |

667 | In a certain hypothetical radioactive decay process, species A decays into species B and species B decays into species ( C ) according to the reactions ( boldsymbol{A} rightarrow 2 boldsymbol{B}+ ) particles ( + )energy ( boldsymbol{B} rightarrow mathbf{2} boldsymbol{C}+boldsymbol{text {particles}}+ )energy The decay constant for species A is ( lambda_{1}=1 s^{-1} ) and that for species B is ( lambda_{2}=100 s^{-1} . ) Initially, ( 10^{4} ) moles of species of A were present while there was none of ( mathrm{B} ) and ( mathrm{C} ). It was found that while there was none of ( B ) and ( C ). It was found that species B reaches its maximum number at a time ( t_{0}= ) ( 2 ln (10) s . ) Calculate the value of maximum number of moles of B | 12 |

668 | A radioactive element X decays by the sequence and with half life given below: ( boldsymbol{X} frac{boldsymbol{alpha}}{mathbf{3 0 m i n}} boldsymbol{Y} frac{mathbf{2} boldsymbol{beta}}{mathbf{2 d a y s}} boldsymbol{Z} ) which of the following statements about this system are correct? A. After two hours, less than ( 10 % ) of the initial ( x ) is left B. An intermediate nuclide exists between Y and Z c. Atomic number of ( x ) and ( z ) are same D. The mass number of Y is greater than ( x ) | 12 |

669 | A non-ecofriendly source of energy is A. Tidal energy B. Wind energy c. Solar energy D. Nuclear energy | 12 |

670 | 42. The rate of decay of a radioactive element at any instant is 10 disintegrations s. If the half-life of the elements is 1 s, then the rate of decay after 1 s will be (a) 500 – (b) 1000 – (c) 250 s- (d) 2000 s- | 12 |

671 | Conceptual Question Three elements ( X, Y, Z ) form a Dobernier traid. The difference in atomic weights between elements ( Y, Z ) is ( 45 . ) If atomic weight of ( X ) is 35 find atomic weight of elements X, Y and Z. | 12 |

672 | The ratio of density of nuclei of ( O^{16} ) and ( C a^{40} ) is: A . 1: 1 B. 1: 2 ( c cdot 1: 3 ) D. 1: 4 | 12 |

673 | Two species of radioactive atoms are mixed in equal number. The disintegration constant of the first species is ( lambda ) and of the second is ( lambda / 3 ) After a long time the mixture will behave as a species with mean life of approximately: A. ( 0.70 / lambda ) d в. ( 2.10 / lambda ) c. ( 1.00 / lambda ) D. ( 0.52 / lambda ) | 12 |

674 | A radioactive substance is being consumed at a rate constant of ( 1 s^{-1} ) After what time will the number of radioactive nuclei become 100. Initially, there were 200 nuclei present A . ( 1 s ) B. ( frac{1}{ln (2)} s ) c. ( ln (2) ) s D. ( 2 s ) | 12 |

675 | Imagine that a reactor converts all given mass into energy and that it operates at a power level of ( 10^{9} W ). The mass of the fuel consumed per hour in the reactor will be (velocity of light, c is ( left.3 times 10^{8} m / sright) ) ( mathbf{A} cdot 0.8 g m ) в. 0.96 gm c. ( 4 times 10^{-2} g m ) D. ( 6.6 times 10^{-5} g m ) | 12 |

676 | Calculate the ground state Q value of the induced fission reaction in the equation ( boldsymbol{n}+_{mathbf{9 2}}^{235} boldsymbol{U} rightarrow_{mathbf{9 2}}^{236} boldsymbol{U}^{*} rightarrow_{40}^{99} boldsymbol{Z} boldsymbol{e}+_{52}^{134} boldsymbol{T} boldsymbol{e}+ ) ( mathbf{3} n ) if the neutron is thermal. A thermal neutron is in the thermal equilibrium with its environment; it has an average kinetic energy given by (3/2) kT. Given: ( $ $ m(n)=1.0087 ) amu, ( mathrm{M}(wedge{235} cup)=235.0439 ) amu, ( M(wedge{99} Z r)=98.916 ) amu ( mathrm{M}(wedge{134} mathrm{Te})=133.9115 ) amu ( $ $ ) | 12 |

677 | Two radioactive substances ( X ) and ( Y ) emit ( alpha ) and ( beta ) particles respectively. Their disintegration constants are in the ratio ( 2: 3 . ) To have equal probabilities of getting emission of ( alpha ) and ( beta ) particles, find the ratio of number of atoms of ( X ) to that of ( Y ) at any time instant. | 12 |

678 | During a negative beta decay. A. An atomic electron is ejected B. An electron which is already present within the nucleus is ejected C. A neutron in the nucleus decays emitting an electron D. A part of the binding energy of the nucleus is converted into an electron | 12 |

679 | A positron and an electron come close together to give a neutral one called A. Electronium B. Positronium c. ( gamma ) -photon D. ( beta ) -particle | 12 |

680 | In the nuclear reaction, there is a conservation of A. momentum B. mass c. energy D. all of these | 12 |

681 | The half life of a radioactive isotope is 3 hours.What is the value of its disintegration constant? A. 0.3 hour ( ^{-1} ) B. 0.693 hour ( ^{-1} ) c. 0.231 hour ( ^{-1} ) D. ( 0.231 min ^{-1} ) | 12 |

682 | Two samples of radioactive substances initially contain equal number of atoms Their half life times are respectively 2 hours and 4 hours. The ratio of their disintegration rates after 12 hours is : A .1: 4 B. 1: 8 c. 3: 4 D. 2: 3 | 12 |

683 | The nuclear reaction is given as ( _{6} C^{11} rightarrow_{5} B^{11}+beta+X . ) Here, ( X ) is? A. A proton B. An electron c. A neutrino D. A neutron | 12 |

684 | E.O. Lawrence was awarded the 1939 Physics Nobel Prize for invention and development of A. diode B. microwave transmitter c. cyclotron D. none of these | 12 |

685 | State radioactive decay law. Prove that radioactive decay is exponential in nature | 12 |

686 | Nuclear fusion produces: ( A cdot ) argon B. deuterium c. helium D. krypton | 12 |

687 | 11. The binding energy per nucleon of deutero CH) and helium nucleus (He) is 1.1 MeV and 7 Mev respectively. If two deuteron nuclei react to form a single helium nucleus, then the energy released is (a) 13.9 MeV (b) 29.9 MeV (c) 23.6 MeV (d) 19.2 MeV (AIEEE 2004) | 12 |

688 | Which one of the following is a possible nuclear reaction? A ( cdot frac{10}{5} B+_{2}^{4} H e rightarrow_{7}^{13} N+_{1}^{1} H ) B ( cdot frac{23}{13} mathrm{Na}+_{1}^{1} mathrm{H} rightarrow_{20}^{20} mathrm{Ne}+_{2}^{4} mathrm{He} ) C ( cdot frac{239}{11} mathrm{Np} rightarrow_{94}^{239} mathrm{Pu}+beta^{-}+bar{v} ) D. ( frac{11}{7} N+_{1}^{1} H rightarrow_{6}^{12} C+beta^{-}+v ) | 12 |

689 | The example of nuclear fusion is: A. Formation of barium and krypton from uranium B. Formation of helium from hydrogen C. Formation of plutonium – 235 from uranium -235 D. Formation of water from hydrogen and oxygen | 12 |

690 | From the following equations, pick out the possible nuclear reactions. This question has multiple correct options ( begin{array}{lllllll}mathbf{C} cdot_{7} N^{14} & + & _{1} H^{1} & rightarrow & 8 & O^{15} & + & 7.3 & M e Vend{array} ) D・ ( _{92} U^{235}+_{0} n^{1} rightarrow_{54} X^{140}+_{38} S i^{94}+ ) ( 20 n^{1}+gamma+200 mathrm{MeV} ) | 12 |

691 | In pair annihilation the least number of ( gamma ) – ray photons produced is : ( A cdot 2 ) B. 3 ( c cdot 4 ) D. | 12 |

692 | Which of the following change the activity of radioisotope? A. Temperature B. Pressure c. chemical environment D. None of the above | 12 |

693 | Isotopes of same element exists in nature.How they differ from each other ( ? ) A. They will have different locations on the periodic table B. They will have different numbers of electrons c. They will have undergo different chemical reactions. D. They have different numbers of protons E. They have different numbers of neutrons | 12 |

694 | Two radioactive sources ( X ) and ( Y ) of half lives ( 1 h ) and ( 2 h ) respectively initially contain the same number of radioactive atoms. At the end of ( 2 h ) their rates of disintegration are in the ratio of : A .4: 3 B. 3: 4 ( c cdot 1: 2 ) D. 2: 1 | 12 |

695 | Fast neutrons can easily be slowed down by: A. The use of lead shield B. Passing them through heavy water c. Elastic collision with heavy nucleus D. Applying a strong electric field | 12 |

696 | The decay of mass during nuclear fission and fusion are: A . ( 0.1 % ) and ( 0.231 % ) B. 0.231% and 0.1% c. ( 0.4 % ) and ( 0.2 % ) D. 0.3% and 0.3% | 12 |

697 | Cadmium rods are used as moderators in a nuclear reactor A. True B. False | 12 |

698 | Assertion Light nuclei are most stable if ( boldsymbol{N}=boldsymbol{Z} ) while heavy nuclei are more stable if ( N>Z .(N rightarrow ) number of neutrons ( Z rightarrow ) number of protons Reason As the number of protons increases in a nucleus, the Coulomb’s repulsive force increases, which tends to break the nucleus apart. So, to keep the nucleus stable, more number of neutrons are needed which are neutral in nature. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

699 | A piece of wood collected from Cro Magnon caves gave 4 dpm. A freshly cut wood of the same weight gives ( 16 d p m ) The cro magnon man lived about years ago (Half life of ( C^{14} ) is 5760 years. Assume the activity is due to ( C^{14} ) only A .5700 в. 2900 c. 11520 D. 1400 | 12 |

700 | A heavy nucleus having mass number 200 gets disintegrated into two small fragments of mass number 80 and 120 If binding energy per nucleon for parent atom is 6.5 MeV and for daughter nucle is ( 7 mathrm{MeV} ) and ( 8 mathrm{MeV} ) respectively, then the energy released in the decay is ( X times ) ( 110 M e V ).Find the value of ( X ) ( A cdot 3 ) B. 4 ( c cdot 2 ) ( D ) | 12 |

701 | 61. A certain radioactive material can undergo three different types of decay, each with a different decay constant 2.22 and 32. Then, the effective decay constant Neff is (a) 62 (b) 42 (c) 22 (d) 32 | 12 |

702 | a) Define atomic mass unit b) Distinguish between molecular mass and molar mass c) Give an example of (i) diatomic, (ii) triatomic molecule of compounds. | 12 |

703 | In sun, the important source of energy is A. proton-proton cycle B. carbon-nirtogen cycle c. carbon-caron cycle D. nitrogen-nitrogen cycle | 12 |

704 | ( 4_{1} H^{1} rightarrow_{2} H e^{4}+2_{+1} e^{0}+ )energy Energy released in this process is [lt is ( operatorname{given} 4_{1} H^{1}=4.031300 mathrm{amu},_{2} H e^{4}= ) ( left.4.0026603 text { amu, } 2_{1} e^{0}=0.01098 text { amu }right] ) A . 14 Mev B. 16.45 Mev c. 37.2 Mev D. ( 32.7 mathrm{Mev} ) | 12 |

705 | Calculate the binding energy of an alpha-particle. Given mass of proton ( = ) 1.0073 a.m.u., mass of neutron ( = ) 1.0087 a.m.u., mass of ( alpha ) -particle ( = ) 4.0015a.m.u. | 12 |

706 | The nuclear reaction ( n+_{5}^{10} B rightarrow_{3}^{7} L i+_{2}^{4} ) He is observed to occur even when very slow-moving neutrons ( left(M_{n}=right. ) 1.0087amu ( ) ) strike a boron atom at rest. For a particular reaction in which ( boldsymbol{K}_{n}=mathbf{0}, ) the helium ( left(boldsymbol{M}_{boldsymbol{H} e}=right. ) ( 4.0026 a m u) ) is observed to have a speed of ( 9.30 times 10^{6} m s^{-1} . ) Determine (a) the kinetic energy of the lithium ( left(M_{L i}=7.0160 a m uright) ) and (b) the ( Q ) value of the reaction. | 12 |

707 | An element ( z M^{A} ) emits one ( alpha ) (alpha) particle followed by two ( beta ) (beta) particles. Among the following, the daughter element is : A ( cdot z-2 M^{A-4} ) B . ( _{z-2} M^{A} ) ( mathbf{c} cdot_{z} M^{A-4} ) D. ( _{z+2} M^{A-4} ) | 12 |

708 | 3. During mean life of a radioactive element, the fraction that disintegrates is (a) e (B) (c) e-1 e-1 | 12 |

709 | The half-life of a radio active nuclide is 0.693 minutes. The time (in minutes) required for the disintegration of this nuclide from 10 grams to one gram is ( mathbf{A} cdot 0.693 ) B. c. 6.93 D. 2.303 | 12 |

710 | Define the atomic mass unit. | 12 |

711 | ( C^{14} ) is: A. a natural non-radioactive isotope B. an artificial non-radioactive isotope C . an artificial radioactive isotope D. a natural radioactive isotope | 12 |

712 | A radioactive sample at any instant has its disintegration rate 5000 disintegration per minute. After 5 minutes, the rate is 1250 disintegrations per minute. Then, the decay constant, per minute, is A . ( 0.4 ln 2 ) B. ( 0.2 ln 2 ) c. ( 0.1 ln 2 ) D. ( 0.8 ln 2 ) | 12 |

713 | The overall process of carbon nitrogen fusion cycle results in the fusion of 4 protons to yield helium nucleus and: A. positron B. two electrons c. two positrons D. an electron | 12 |

714 | The reaction ( _{1}^{2} boldsymbol{H}+_{1}^{2} boldsymbol{H} rightarrow_{2}^{3} boldsymbol{H} boldsymbol{e}+_{0}^{1} boldsymbol{n} ) is called A. Fusion B. Fission c. Endothermic reaction D. Spontaneous reaction | 12 |

715 | Two radioactive materials ( boldsymbol{X}_{1} ) and ( boldsymbol{X}_{2} ) have decay constants ( 6 lambda ) and ( 3 lambda ) respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of ( X_{1} ) to that of ( X_{2} ) will be ( frac{1}{e} ) after a time. A ( cdot frac{1}{6 lambda} ) B. ( frac{1}{3 lambda} ) c. ( frac{3}{6 lambda} ) D. ( frac{6}{9 lambda} ) | 12 |

716 | 56. To generate a power of 3.2 mega watt, the number of fissions of U233 per minute is (Energy released per fission=200 MeV, leV=1.6 x 10-‘J) (a) 6 x 1018 (b) 6 x 1017 (c) 1017 (d) 6 x 1016 | 12 |

717 | A nucleus of element ( X ) is represented ( operatorname{as}_{26}^{56} X ) Which is an isotope of element ( X ? ) ( A cdot frac{26}{56} X ) B ( cdot frac{54}{26} X ) ( mathbf{c} cdot underset{24}{56} X ) ( mathrm{D} cdot_{28}^{54} mathrm{X} ) | 12 |

718 | ( C l^{35} ) and ( C l^{37} ) are: A. isomers B. isotopes c. isomorphous D. isobars | 12 |

719 | One curie is equal to A ( .3 .7 times 10^{10} ) disintegration / sec B. ( 3.2 times 10^{8} ) disintegration/sec c. ( 2.8 times 10^{10} ) disintegration / sec D. None of these | 12 |

720 | A radioactive element ( X_{90}^{238} ) decays into ( Y_{83}^{222} . ) The number of ( beta ) -particles emitted are ( A ) B. 2 ( c cdot 4 ) D. 6 | 12 |

721 | If mass-energy equivalence is taken into account, when water is cooled to form ice, the mass of water should ( A ). increase B. remain unchanged c. decrease D. first increase then decrease | 12 |

722 | The correct statement is A. the nucleus ( _{3}^{6} L i ) can emit an alpha particle B. the nucleus 210 84 Po can emit a proton C . deuteron and alpha particle can undergo complete fusion | 12 |

723 | 60. If mass of U235 = 235.12142 amu, mass of U236 = 236.1205 amu and mass of neutron = 1.008665 amu, then the energy required to remove one neutron from the nucleus U236 is nearly about (a) 75 MeV (b) 6.5 MeV (c) 1 eV (d) zero | 12 |

724 | 1 amu is equal to ( 1.66 times 10^{-24} ) g. A. True B. False | 12 |

725 | Among the following which is used in the nuclear reactor as a moderator? A. copper B. boron c. graphite D. None of these | 12 |

726 | Sun radiates energy at the rate of ( 3.6 times ) ( 10^{26} ) Joule/s. The rate of decrease in mass of the sun is ( left(text { in } mathrm{kgs}^{-1}right) ) A ( .12 times 10^{10} ) B . ( 1.3 times 10^{20} ) c. ( 4 times 10^{9} ) D . ( 3.6 times 10^{36} ) | 12 |

727 | The nuclide which disintegrates by emitting a ( beta ) – particle to form ( _{7}^{14} ) N contains: A. 8 neutrons B. 10 neutrons c. 7 neutrons D. 6 neutrons | 12 |

728 | 30. The speed of daughter nuclei is (a) 2Δm c Δη “- Μ + Δm (b) o M m ΔΜ • • 1 | 12 |

729 | The relation between half life ( (T) ) and decay constant ( (lambda) ) is A ( . lambda T=1 ) в. ( lambda T=frac{1}{2} ) c. ( lambda T=log _{e} 2 ) D. ( lambda=log 2 T ) | 12 |

730 | 1 amu is equal to A ( cdot 1.67 times 10^{-27} k g ) В. ( 1.67 times 10^{27} k g ) c. ( 1.67 times 10^{-37} k g ) D. ( 1.67 times 10^{37} k g ) | 12 |

731 | Which of the following will produce more energy in a short time? A. nuclear fission B. nuclear fusion c. both will produce the same amount of energy D. none of these | 12 |

732 | Nuclear fusion occur in A. Atom bomb B. Hydrogen bomb C. Neutron bomb D. None of these | 12 |

733 | In a nuclear reaction, ( _{1}^{2} boldsymbol{H}+_{1}^{2} boldsymbol{H} longrightarrow_{2}^{3} boldsymbol{H} boldsymbol{e}+_{0}^{1} boldsymbol{n} ) if the masses of ( _{1}^{2} H ) and ( _{2}^{3} H e ) are ( mathbf{2 . 0 1 4 7 4 1} ) amu and ( mathbf{3 . 0 1 6 9 7 7} ) amu respectively, then the ( Q ) -value of the reaction is nearly: B. 3.57 Mev c. 0.82 Mev D. 2.45 MeV | 12 |

734 | Identify the correct ascending order of ( boldsymbol{alpha}, boldsymbol{beta} ) and ( gamma ) with reference to their ionizing power: I) ( alpha ) -ray II) ( gamma ) -ray III) ( beta ) -ray A . “।,॥,।, в. ।,॥।, c. ॥,।,॥| D. I,II,II | 12 |

735 | A bone fragment found in a cave contains 0.21 times as much ( _{6}^{14} mathrm{C} ) as in equal amount of carbon in air when the organism containing bone died. Find the approximate age of fragment ( t_{1 / 2} ) of ( frac{14}{6} mathbf{C}=5730 ) years A ( cdot 1.15 times 10^{4} y ) B. ( 1.3 times 10^{4} y ) c. ( 1.24 times 10^{4} y ) D. ( 1.4 times 10^{4} y ) | 12 |

736 | When ( _{3} L i^{7} ) nuclei are bombarded by protons and the resultant nuclei are ( 4 B e^{8}, ) the emitted particles will be: A. alpha particles B. beta particles c. gamma particles D. neutrons | 12 |

737 | How many ( alpha ) and ( beta ) -particles should be eliminated so that an isodiaphere is formed? ( mathbf{A} cdot n alpha, n beta ) B . ( n alpha,(n+1) beta ) ( c cdot n a ) D. ( n beta ) | 12 |

738 | 10. A nucleus is disintegrated into two nuclear parts havin velocities in the ratio 2 : 1. The ratio of their nuclear size will be (a) 213 : 1 (b) 1:32 (c) 31/2. 1 n (d) 1:213 (AIEEE 2001 | 12 |

739 | At some instant, a radioactive sample ( boldsymbol{S}_{1} ) having an activity ( 5 mu C i ) has twice the number of nuclei as another sample ( S_{2} ) which has an activity of ( 10 mu C ) i. The half lives of ( S_{1} ) and ( S_{2} ) are A. 20 years and 5 years, respectively B. 20 years and 10 years, respectively c. 10 year each D. 5 year each | 12 |

740 | List two advantages of power production by nuclear fusion, over nuclear fission. | 12 |

741 | Which one of the following statements is/are correct? This question has multiple correct options A. Neutron was discovered by Chadwick. B. Nuclear filsion was discovered by Hahn and Strassmann C. Polonium was discovered by Madam Curie D. Nuclear fusion was discovered by Fermi | 12 |

742 | The disposal of waste produced in a nuclear power plant is difficult because they are: A. highly inflammable B. highly radioactive c. highly poisonous D. extremely heavy | 12 |

743 | The splitting of a heavy nucleus with neutron into two smaller nuclei along with the release of a large amount of energy is known as A. nuclear fusion B. nuclear fission c. radioactive decay D. none of the above | 12 |

744 | The energy equivalent of 1 amu is A. 931 eV th В. ( 93.1 V ) ( mathbf{c} .931 mathrm{MeV} ) D. ( 9.31 mathrm{MeV} ) | 12 |

745 | 2. At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit (i) electrons (ii) protons (ii) He2+ (iv) neutrons The emission at the instant can be (a) i, ii, iii (b) i, ii, iii, iv (c) iv (d) ii, iii (AIEEE 2002) | 12 |

746 | The energy equivalent of 1 g of matter is A ( cdot 9 times 10^{13} ) joule B. ( 9 times 10^{13} ) erg c. ( 3 times 10^{5} ) joule D. ( 3 times 10^{5} ) erg | 12 |

747 | The type of reactions considered to be the principal sources of energy in stars is ( _{-}–_{-}- ) when hydrogen is converted to helium. A. nuclear fission B. nuclear fusion c. radioactive decay D. none of the above | 12 |

748 | 13. Which sample contains greater number of nuclei a 5.00- uCi sample of 24UPu (half-life 6560y) or a 4.45-UC; sample of 243 Am (half-life 7370 y) (a) 240pu (b) 243 AM (c) Equal in both (d) None of these | 12 |

749 | A ( 2 M e V ) neutron is emitted in a fission reactor. If it looses half of its kinetic energy in each collision with a moderator atom, how many collisions must it undergo to achieve thermal energy of ( 0.039 e V ? ) A . 20 B. 26 c. 30 D. 42 E . 48 | 12 |

750 | toppr ( 5 tau . ) The decay products in both cases are stable. A plot is made of the total number of radioactive nuclei as a function of time. Which of the following figures best represents the form of this plot? ( A ) B. ( c ) ( D ) | 12 |

751 | Who was the Indian scientist who was primarily responsible for setting of nuclear reactors in India? A. H. J. Bhabha B. V. A. Sarabhai c. Dr. A. P. J. Abdul Kalam D. G. Madhavan Nair | 12 |

752 | In the nuclear reaction ( boldsymbol{n}+_{mathbf{9 2}}^{235} boldsymbol{U} rightarrow_{mathbf{5 4}}^{boldsymbol{a}} boldsymbol{X} boldsymbol{e}+_{boldsymbol{b}}^{mathbf{9 4}} boldsymbol{S r}+mathbf{2 n} ) determine the values of a and ( b ) | 12 |

753 | A nucleus of mass ( M+Delta m ) is at rest and decays into two daughter nuclei of equal mass of ( frac{M}{2} ) each. The speed of light is c,Then speed of daughter nuclei is? A ( cdot c frac{Delta mathrm{m}}{mathrm{M}+Delta mathrm{m}} ) B. ( mathrm{c} sqrt{frac{2 Delta mathrm{m}}{mathrm{M}}} ) ( ^{c} cdot c sqrt{frac{Delta m}{M}} ) D ( cdot sqrt{frac{Delta m}{M+Delta m}} ) | 12 |

754 | The masses of ( alpha ) -particle, proton and neutron are 4.00150 amu, 1.00728 amu and 1.00867 amu respectively. Binding Energy per nucleon of ( alpha ) -particle is : begin{tabular}{l} A .2835 \ hline end{tabular} в. 931.5 Ме ( V ) c. ( 28.3 mathrm{MeV} ) D. ( 7.08 mathrm{MeV} ) | 12 |

755 | ( 92 U^{238} rightarrow 82 p b^{206}+8_{2}^{4} H e . ) The number of ( beta ) particles released in this reaction is : ( mathbf{A} cdot mathbf{6} ) B. 3 c. 1 D. 10 | 12 |

756 | 68. K isotope of potassium has a half-life of 1.4 x 10yr and decays to form stable argon, 18 Ar. A sample of rock has been taken which contains both potassium and argon in the ratio 1:7, i.e., Number of potassium-40 atoms 1 Number of argon-40 atoms 7 Assuming that when the rock was formed no argon-40 was present in the sample and none has escaped subsequently, determine the age of the rock. (a) 4.2 x 10 years (b) 9.8 x 109 years (c) 1.4 x 10 years (d) 10 x 10 years 25 | 12 |

757 | The probability of a radioactive nucleus to survive one mean life is ( frac{1}{e+x}, ) then ( x ) is | 12 |

758 | A nucleus at rest undergoes ( boldsymbol{alpha}- ) decay emitting an ( alpha- ) particle of de Broglie wavelength ( lambda=5.76 times 10^{-15} mathrm{m} . ) If the mass of the daughter nucleus is 223.610 amu and that of the ( alpha- ) particle is 4.002 amu, determine the total kinetic energy in the final state, Hence, obtain the mass of parent nucleus in amu. ( (1 a m u= ) ( left.mathbf{9 3 1 . 4 7 0} M e V c^{-mathbf{2}}right) ) | 12 |

759 | The percentage efficiency of nuclear fission is ( _{-}-_{-}-_{-}- ) that of nuclear fusion. A. higher than B. lower than c. same as D. may be higher, lower or same | 12 |

760 | A radioactive nucleus can decay by two different processes. The mean value period for the first process is ( Z_{1} ) and that for the second process is ( Z_{2} ). The effective mean value period for the two processes is: A ( cdot frac{Z_{1}+Z_{2}}{2} ) в. ( Z_{1}+Z_{2} ) c. ( sqrt{Z_{1} Z_{2}} ) D. ( frac{Z_{1} Z_{2}}{Z_{1}+Z_{2}} ) | 12 |

761 | Sun maintains its shining because of A. the fission of helium B. chemical reactoin c. fusion of hydrogen nuclei D. burning of carbon | 12 |

762 | After an interval of one day, ( frac{1}{16} t h ) initia amount of a radioactive material remains in a sample. Then, its half-life is ( mathbf{A} cdot 6 h ) в. ( 12 h ) ( c .1 .5 h ) D. ( 3 h ) | 12 |

763 | An uncontrolled nuclear chain reaction forms the basis of: A. hydrogen bomb B. atom bomb c. hydro electric power plant D. nuclear power plant | 12 |

764 | A vessel of ( 125 mathrm{cc} ) contains ( _{1}^{3} mathrm{H}left(t_{1 / 2}=right. ) 12.3 ( y ) ) at ( 500 mathrm{kPa} ) and ( 300 mathrm{K} ). Find the activity of the gas A. ( 0.754 mathrm{Ci} ) в. 7.24 Сг c. ( 72.4 mathrm{Ci} ) D. 724 С( i ) | 12 |

765 | toppr Q Type your question decay products of the neutron. Therefore, considering the decay of a neutron as a two-body decay process, it was predicted theoretically that the kinetic energy of the electron should be a constant. But experimentally, it was observed that the electron kinetic energy has a continuous spectrum. Considering a three-body decay process, i.e. ( boldsymbol{n} rightarrow boldsymbol{p}+boldsymbol{e}^{-}+overline{boldsymbol{v}}_{e}, ) around 1930, Pauli explained the observed electron energy spectrum. Assuming the anti-neutrino ( left(bar{v}_{e}right) ) to be massless and possessing negligible energy, and the neutron to be at rest, momentum and energy conservation principles are applied. From this calculation, the maximum kinetic energy of the electron is ( 0.8 times 10^{6} e V . ) The kinetic energy carried by the proton is only the recoil energy. f the anti-neutrino had a mass of 3 ( e V / c^{2}(text { where } c ) is the speed of light) instead of zero mass, what should be the range of the kinetic energy, ( boldsymbol{K}, ) of the electron? A. ( 0 leq K leq 0.8 times 10^{6} e V ) B . ( 3.0 e V leq K leq 0.8 times 10^{6} c V ) c. ( 3.0 e V leq K<0.8 times 10^{6} e V ) D. ( 0 leq K<0.8 times 10^{6} e V ) | 12 |

766 | Half life of a radio active element is 5 min 10 sec. Time taken for ( 90 % ) of it to disintegrate is nearly This question has multiple correct options A. 100 min B. 1000 sec ( mathrm{c} cdot 10^{4} mathrm{sec} ) D. ( 10^{4} ) min | 12 |

767 | Find the ( Q ) -value and the kinetic energy of the emitted ( alpha ) – Particle in the ( alpha ) -decay of ( (a)_{86}^{220} R n ) and (b) 226 88 Ra. Given: ( boldsymbol{m}left(_{mathbf{8 8}}^{226} boldsymbol{R} boldsymbol{a}right)=mathbf{2 2 6 . 0 2 5 4 0} boldsymbol{u} ) ( boldsymbol{m}left(_{86}^{222} boldsymbol{R} boldsymbol{n}right)=mathbf{2 2 2 . 0 1 7 5 0} boldsymbol{u} ) ( boldsymbol{m}left(_{84}^{216} boldsymbol{P o}right)=mathbf{2 1 6 . 0 0 1 8 9} boldsymbol{u} ) | 12 |

768 | How much energy must be imparted to the proton so as to start the reaction? ( ^{7} L i_{3}+^{1} H_{1} rightarrow_{4} B e^{7}+_{0} eta^{1} ) Given the mass of the atoms; ( _{3}^{7} L i-7.01600_{, 1}^{1} H-1.00783_{, 4}^{7} B e- ) ( mathbf{7 . 0 1 6 9 3}_{.0} mathbf{n}-mathbf{1 . 0 0 8 6 6} ) | 12 |

769 | An ( alpha ) -particle is bombarded on ( ^{14} mathrm{N} ). As a result, a ( ^{17} ) O nucleus is formed and a particle is emitted. This particle is a A. neutron B. proton c. electron D. positron | 12 |

770 | The atomic mass of ( 7^{N^{15}} ) is 15.000108 a.m.u. and that is of ( 8^{circ}^{16} 15.994915 ) a.m.u. If the mass of a proton is 1.007825 a.m.u. then the minimum energy provided to remove the least tightly bound proton is B. 12.13 Mev c. 13.018 Mev D. 12.13 ev | 12 |

771 | ( ln beta^{+} ) decay process, the following changes take place inside the nucleus A ( cdot frac{A}{Z} X longrightarrow_{Z-1}^{A} Y+e^{+}+gamma ) B . ( _{Z} X longrightarrow_{Z+1}^{A} Y+e^{-}+gamma ) ( mathbf{c} cdot_{Z}^{A} X longrightarrow_{Z}^{A} Y+e^{-}+gamma ) D ( cdot frac{A}{Z} X longrightarrow_{Z}^{A} Y+e^{-}+bar{gamma} ) | 12 |

772 | of relative danger 78. Three radioactive sources A, B and C of same activity 25 m Ci are dumped in a pond as waste. Source A emits 1.0 MeV y-rays, source B emits 2.0 MeV y-rays, and source Cemits 2.0 MeV O-rays. Order of relative of A, B and C is (a) ABC (b) B > A >C (c) C>B>A (d) A = B = C | 12 |

773 | Which of the following is the radio isotope in this pair? ( mathbf{1 2} mathbf{C}, mathbf{1 4} mathbf{C} ) ( mathbf{6} ) A ( cdot frac{12 C}{6} ) B. ( 14 C ) c. Both of them D. None of them | 12 |

774 | Assertion ( gamma ) -radiation emission occurs after ( boldsymbol{alpha} ) and ( beta ) decay. Reason Energy levels occur in nucleus. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion. C. Assertion is correct but Reason is incorrect. D. Both Assertion and Reason are incorrect. | 12 |

775 | Fill in the blanks: kg coal can light up 1 bulb for hours. ( A cdot 6 ) B. 8 c. 7 D. 5 | 12 |

776 | The fusion of two nuclide will require a temp of order of ( mathbf{A} cdot 10^{6} K ) B . ( 10^{7} K ) ( mathbf{c} cdot 10^{8} K ) D cdot ( 10^{9} K ) | 12 |

777 | Assertion Most nuclear power stations in India have been constructed near sources of water Reason Nuclear power stations require a great quantity of water cooling purposes. A. Both A and R are true and R explains A. B. Both A and R are true but R does not explain A c. A is true and R is false. D. A is false and R is true | 12 |

778 | Assertion: The reaction; ( _{1} boldsymbol{H}^{2}+_{0} boldsymbol{n}^{1} rightarrow ) ( _{2} H e^{4}+_{0} n^{1} ) will not happen Reason: The equation given is not balanced. A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion c. Assertion is true but Reason is false D. Assertion is false but Reason is true E. Both Assertion and Reason are false | 12 |

779 | The atomic mass of ( _{11}^{23} mathrm{Na} ) in amu is : | 12 |

780 | Consider the following statements (A) and (B) and identify the correct answer given below: Statement A: Positive values of packing fraction implies a large value of binding energy Statement B: The difference between the mass of the nucleus and the mass number of the nucleus is called the packing fraction A. A and B are correct B. A and B are false c. A is true, B is false D. A is false, B is true | 12 |

781 | Best neutron moderator is. A. Beryllium oxide B. Pure water c. Graphite D. Heavy water | 12 |

782 | A substance contains ( 35.0 g ) nitrogen, ( 5.05 g ) hydrogen, and ( 60.0 g ) oxygen. How many grams of oxygen are there in a ( 200 g ) sample of the substance? A. ( 10.1 g ) B. ( 60.0 g ) c. ( 70.0 g ) D. 1209 E . ( 140 g ) | 12 |

783 | The mass of chlorine ( left(_{17} C l^{35}right) ) atom is 34.98 amu, mass of proton ( =1.007825 ) amu, mass of neutron= 1.008665 amu Then binding energy is : ( mathbf{A} cdot 287.83 mathrm{Mev} ) B. 287.83 joules c. 8.22 Mev D. 8.22 joule | 12 |

784 | A radioactive nucleus A finally transforms into a stable nucleus B. Then, A and B may be A. isobars B. isotones c. isotopes D. none of these | 12 |

785 | ILLUSTRATION 30.6 What is the wavelength of the 0.186 MeV X-ray photon emitted by radium 33″ Ra ? | 12 |

786 | Modern atomic mass scale is based on the mass of ( mathbf{A} cdot H-1 ) B. ( C-12 ) c. ( C-14 ) D. ( C-16 ) | 12 |

787 | In which of the following decays the element reduced does not change? A. ( alpha ) -decay B. ( beta^{+} ) -decay c. ( beta^{-} ) -decay D. ( gamma ) -decay | 12 |

788 | Energy released in a nuclear reaction is given by | 12 |

789 | The fissionable material used in a breeder reactor is A ( cdot 92 mathrm{U}^{235} ) 55 В ( cdot ) g ( _{9} mathrm{Pu}^{239} ) ( mathrm{c} cdot_{90} mathrm{Th}^{234} ) D. ( c^{12} ) | 12 |

790 | How is nuclear power derived? A. It is derived from energy i.e. released when relatively large atoms of uranium, thorium are split by shooting neutrons on them. B. It is derived from energy i.e. released when relatively small atoms of uranium, thorium are split by shooting neutrons on them. C. It is derived from energy i.e. released when relatively large atoms of uranium, thorium are split by shooting electrons on them. D. None | 12 |

791 | ( 1.00 g ) of ( E u C l_{2} ) is treated with excess of aqueius ( A g N O_{3} ) and all the chlorine is recovred as ( 1.29 mathrm{g} ) of ( A G c L . ) Calculate the atomic weight of ( boldsymbol{E u}(boldsymbol{C l}= ) ( mathbf{3 5 . 5}, boldsymbol{A} boldsymbol{g}=mathbf{1 0 8}) ) | 12 |

792 | The particle ( X ) in the following nuclear reaction is ( _{5}^{B} 10+_{2}^{H e} 4 longrightarrow_{7}^{N} 13+X ) A. ( P ) в. ( c cdot e ) D. | 12 |

793 | Assertion The average mass of one Mg atom is 24.305 amu, which is not equal to the actual mass of one Mg atom. Reason Three isotopes, ( ^{24} M g,^{25} M g ) and ( ^{26} M g ) of Mg can be found in nature. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

794 | The number of ( U^{238} ) nuclei in a rock sample is equal to the number of ( mathrm{Pb}^{206} ) atoms. The half-life of ( mathrm{U}^{238} ) is ( 4.5 times 10^{9} ) years.The age of the rock is A ( cdot 4.5 times 10^{9} y ) B. ( 9 times 10^{9} y ) C. ( 13.5 times 10^{9} y ) D. ( 18 times 10^{9} y ) | 12 |

795 | What, according to you, were the values displayed by Asha and her mother? | 12 |

796 | Positronium is converted into A. 2 Photons each of energy ( 0.51 mathrm{MeV} ) B. 1 Photon of energy 1.02 MeV C. 2 Photons each of energy 1.02MeV D. 1 Photon of energy ( 0.51 mathrm{MeV} ) | 12 |

797 | Fill in the blanks. Fissionable isotope of uranium is | 12 |

798 | Two radioactive sources ( A ) and ( B ) initially contain equal number of radioactive. Source ( boldsymbol{A} ) has a half-life of 1 hour and source ( B ) has a half-life of 2hours. the ratio of the rate of disintegration of ( boldsymbol{A} ) to that of ( boldsymbol{B} ) is: A .1: 2 B . 2: 1 c. 1: 1 D. 1: 4 | 12 |

799 | The unified atomic mass unit is the standard unit that is used for indicating mass on an atomic or molecular scale. If true enter 1 , else enter 0 | 12 |

800 | Choose the correct options – This question has multiple correct options A. In a nuclear reactor, the function of the moderator, is to slow down neutrons B. 1 MeV energy is ( 1.6 times 10^{-13} J ) C . A nucleus ( _{Z}^{A} X ) emits an ( alpha- ) particle. The resultant nucleus emits a ( beta^{+}- ) particle. The respective atomic and mass nos. of the final nucleus will be ( z-3, A-4 ) D. The mass equivalent of 931 MeV energy is ( 1.66 times ) ( 10^{-27} k g ) | 12 |

801 | In the nuclear reaction ( _{1} H^{2}+_{1} H^{2} rightarrow_{2} ) ( H e^{3}+_{0} n^{1} ) if the mass of the deuterium atom ( =2.014741 a m u, ) mass of ( _{2} H e^{3} ) atom ( =3.016977 a m u, ) and mass of neutron ( =1.008987 a m u, ) then the ( Q ) value of the reaction is nearly A. 0.00352 Mev B. 3.27 MeV c. 0.82 Mev D. 2.45 MeV | 12 |

802 | In the nuclear reaction ( _{90} T h^{232} rightarrow_{82} ) ( P b^{208} . ) The number of ( alpha ) and ( beta ) particles emitted are: ( mathbf{A} cdot 1 alpha, 4 beta ) B. ( 2 alpha, 2 beta ) ( mathbf{c} cdot 6 alpha, 4 beta ) D. ( 8 alpha, 4 beta ) | 12 |

803 | The radioactive decay of uranium into thorium is expressed by the equation ( 92 U^{238} rightarrow 90 T h^{234}+X ) Where ( X ) is A. an electron B. a proton c. a deuteron D. an alpha particle | 12 |

804 | Find the atomic number and mass number of the last member in the following series: (a) ( _{88}^{226} R a stackrel{-alpha}{longrightarrow} R n quad-alpha ) ( boldsymbol{R} boldsymbol{a} boldsymbol{A} stackrel{-boldsymbol{alpha}}{longrightarrow} boldsymbol{R} boldsymbol{a} boldsymbol{B} stackrel{-boldsymbol{beta}}{longrightarrow} boldsymbol{R} boldsymbol{a} boldsymbol{C} ) (b) ( _{Z}^{M} A stackrel{-alpha}{A} B^{-beta} C^{-beta} ) ( boldsymbol{D} stackrel{-boldsymbol{alpha}}{longrightarrow} boldsymbol{E} ) | 12 |

805 | Average power developed in time ( t ) due to the decay of the radionuclide is A ( cdotleft(frac{q_{0} t}{2}-frac{q_{0}}{lambda}+frac{q_{0}}{lambda^{2} t}-frac{q_{0}}{lambda^{2} t} e^{-lambda t}right) E_{0} ) B. ( left(frac{q_{0} t}{2}+frac{q_{0}}{lambda}+frac{q_{0}}{lambda^{2} t}-frac{q_{0}}{lambda^{2} t} e^{-lambda t}right) E_{0} ) c. ( left(frac{q_{0} t}{2}-frac{q_{0}}{lambda}+frac{q_{0}}{lambda^{2} t}+frac{q_{0}}{lambda^{2} t} e^{-lambda t}right) E_{0} ) D. ( left(frac{q_{0} t}{2}+frac{q_{0}}{lambda}+frac{q_{0}}{lambda^{2} t}+frac{q_{0}}{lambda^{2} t} e^{-lambda t}right) E_{0} ) | 12 |

806 | Which of the following relations is correct? A. ( E=m c ) B . ( E=m c^{2} ) c. ( E=2 m c^{2} ) D. ( E=m c^{2} / 4 ) | 12 |

807 | If the half-life period of a radioactive substance is 0.693 years, what is its decay constant? A. 0.2 year ( ^{-1} ) B. 0.1 year ( ^{-1} ) c. 0.5 year ( ^{-1} ) D. 1 year ( ^{-1} ) | 12 |

808 | A radio isotope ‘X’ with a half life ( 1.4 times ) ( 10^{9} ) years decays to ‘Y’ which is stable. A sample of the rock from a cave was found to contain ‘ ( X ) ‘ and ‘ ( Y ) ‘ in the ratio 1 : 7. The age of the rock is A ( cdot 1.96 times 10^{9} )years В. ( 3.92 times 10^{9} ) years c. ( 4.20 times 10^{9} ) years D. ( 8.40 times 10^{9} ) years | 12 |

809 | (a) In a typical nuclear reaction e.g ( _{1}^{2} boldsymbol{H}+_{1}^{2} boldsymbol{H} rightarrow_{2}^{3} boldsymbol{H}+_{0}^{1} boldsymbol{n}+mathbf{3} .2 mathbf{7} M e boldsymbol{V} ) although number of nucleons is conserved, yet energy is released, How? Explain. (b) Show that nuclear density in a given nucleus is independent of mass number A. | 12 |

810 | ( _{1}^{2} boldsymbol{H}+_{1}^{3} boldsymbol{H} rightarrow_{0}^{1} boldsymbol{n}+mathbf{X} ) The product ( X ) in the nuclear reaction represented is. A ( cdot frac{1}{1} H ) в. ( _{2}^{3} mathrm{He} ) ( mathrm{c} cdot_{2}^{4} mathrm{He} ) D. ( frac{4}{3} L i ) ( E cdot_{3}^{5} L i ) | 12 |

811 | Fusion reaction takes place at about : A ( cdot 9 times 10^{2} K ) В. ( 3 times 10^{3} K ) ( mathbf{c} cdot 3 times 10^{4} K ) D. ( 3 times 10^{6} K ) | 12 |

812 | To convert ( _{90} T h^{232} ) into ( _{90} T h^{228}, ) the least number of ( alpha ) and ( beta ) particles that have to be emitted are respectively. ( A cdot 1,1 ) B. 2, ( c cdot 1,2 ) D. 2, 2 | 12 |

813 | Fast neutrons can easily be slowed down by A. the use of lead shielding B. passing them through water c. elastic collision with heavy nuclei D. applying a strong electric field | 12 |

814 | In stars, when many hydrogen nuclei in the nuclear reaction are joined, is called as: A. mass defect B. sunburn c. fusion reaction D. fission reaction E. helium reaction | 12 |

815 | One mole of radium has an activity of ( 1 / 3.7 ) killo curie. Its decay constant will be A ( cdot frac{1}{6} times-10 s^{-1} ) В. ( 10^{-10} s^{-1} ) ( mathbf{c} cdot 10^{-11} s^{-1} ) D. ( 10^{-8} s^{-1} ) | 12 |

816 | Two radioactive substances ( X ) and ( Y ) initially contain equal number of atoms Their half-lives are 1 hour and 2 hours respectively. Then the ratio of their rates of disintegration after four hours is: A . 1: 1 B . 2: 1 c. 1: 2 D. 2: 3 | 12 |

817 | Two radioactive materials ( A ) and ( B ) have decay constants 5 lambda and ( lambda ) respectively. Initially both ( A ) and ( B ) have the same number of nuclei. The ratio of the number of nuclei of ( A ) to that of ( B ) will be ( frac{1}{e} ) after a time A ( cdot frac{1}{5 lambda} ) в. ( frac{1}{4 lambda} ) ( c cdot frac{5}{4 lambda} ) D. ( frac{4}{5 lambda} ) | 12 |

818 | In Carbon-Nitrogen fusion cycle protons are fused to form a helium nucleus, positrons and release some energy.The number of protons fused and the number of positrons released in this process respectively are ( A cdot 4,4 ) B. 4,2 ( c cdot 2,4 ) D. 4,6 | 12 |

819 | Where was the first nuclear explosion by India was carried out? A. Puskar B. Narora c. Pokhran D. Mumbai | 12 |

820 | Unit of radioactivity is : A. Fermi B. Farad c. Curie D. Hertz | 12 |

821 | The relation between the volume ( V ) and the mass ( M ) of a nucleus is: A. ( V propto M^{3} ) B ( cdot V propto M^{1 / 3} ) c. ( V propto M ) D. ( V propto 1 / M ) | 12 |

822 | Consider the following statements: ( A: p-p, p-n, n-n ) forces between nucleons are not equal and charge dependent B: In nuclear reactor the fission reaction will be in accelerating state if the value of neutron reproduction factor ( k>1 ) A. Both A and B are correct B. Both A and B are wrongg C. A is wrong and B is correct D. A is correct and B is wrong | 12 |

823 | When an ( alpha ) -particle is ejected, the atomic number of the atom decreases by | 12 |

824 | 76. Why is a He nucleus more stable than a Li nucleus? (a) The strong nuclear force is larger when the neutron to proton ratio is higher. (b) The laws of nuclear physics forbid a nucleus from containing more protons than neutrons. (c) Forces other than the strong nuclear force make the lithium nucleus less stable. (d) None of the above. | 12 |

825 | The half-life of ( ^{215} A t ) is ( 100 mu ) s. The time taken for the radioactivity of a sample of ( ^{215} A t ) to decay to ( 1 / 16 ) th of its initial value is A. ( 400 mu s ) B. ( 6.3 mu s ) c. ( 40 mu s ) D. 300mus | 12 |

826 | Composition of the nuclei of two atomic species ( X ) and ( Y ) are given as under [ begin{array}{r} boldsymbol{X} boldsymbol{Y} \ text { Protons }=boldsymbol{6} end{array} ] Neutrons ( =mathbf{6} ) Given the mass numbers of ( X ) and ( Y ). What is the relation between the two species? | 12 |

827 | Which energy is produced by nuclear fission or nuclear fusion? A. Thermal Energy B. Geothermal energy C. Nuclear energy D. Tidal Energy | 12 |

828 | Identify which of the following equations represents alpha decay in a nuclear fission reaction? ( begin{array}{ll}text { A } cdot & frac{2}{1} H+_{1}^{2} H rightarrow quad_{1}^{3} H+_{1}^{1} H+text { energy } \ & text { y } Hend{array} ) B ( cdot frac{226}{88} R a rightarrow quad frac{222}{86} R n+_{2}^{4} H e ) ( begin{array}{ll}text { C. }_{83}^{209} B i rightarrow & frac{209}{84} P o+_{-1}^{0} e \ & eend{array} ) D ( cdot frac{235}{92} U+_{0}^{1} n rightarrow quad frac{140}{54} X e+_{38}^{94} S r+_{2}^{1} n ) E ( cdot frac{4}{2} mathrm{He}+_{13}^{27} mathrm{Al} rightarrow quad_{15}^{30} mathrm{P}+_{0}^{1} n ) | 12 |

829 | Atoms having the same but different ( _{-1-} ) are called isotopes. | 12 |

830 | 14. If the radius of a 13 Al nucleus is estimated to be 36 im. then the radius of a Te nucleus is nearly (a) 5 fm (b) 4 fm (c) 8 fm (d) 6 fm (AIEEE 2005) | 12 |

831 | Explain the alpha and beta decay in radioactivity | 12 |

832 | Find the angle in degrees through which the photon is scattered in the scattering event described. ( mathbf{A} cdotleft(3 times 10^{-3}right) ) B ( cdotleft(3 times 10^{-5}right) ) C ( cdotleft(3 times 10^{-7}right) ) D. ( left(3 times 10^{-9}right) ) | 12 |

833 | The unit of rate constant for a zero order reaction is: A ( cdot s^{-1} ) B. ( m o l L^{-1} s^{-1} ) c. ( L m o l^{-1} s^{-1} ) D. ( L^{2} m o l^{-2} s^{-1} ) | 12 |

834 | ( _{11} N a^{22} ) and ( _{10} N e^{22} ) are A. Isotopes B. Isomers c. Isotones D. Isobars | 12 |

835 | 33. Assume that a neutron breaks into a proton and an electron. The energy released during this process is: (mass of neutron = 1.6725 x 10-27 kg mass of proton = 1.6725 x 104 kg, mass of electron = 9 x 10-31 kg) (a) 0.73 MeV (b) 7.10 MeV (c) 6.30 MeV (d) 5.4 MeV (AIEEE 2012) | 12 |

836 | f ( 1 u=1.492 times 10^{-a} ) erg; the value of ( a ) is : | 12 |

837 | Complete the equation for the following fission process ( _{92} U^{235}+_{0} n^{1} rightarrow_{38} ) ( boldsymbol{S} boldsymbol{r}^{boldsymbol{9 0}}+ldots ) В ( cdot_{54} X e^{14} ) ( mathrm{c} cdot_{57} mathrm{Xe}^{142} ) ( mathrm{D} cdot_{54} X e^{142}+3_{0} ) | 12 |

838 | The energy of thermal neutrons is nearly A ( .0 .25 mathrm{eV} ) B. ( 0.025 mathrm{eV} ) c. ( 200 mathrm{MeV} ) D. 0.025 Joule | 12 |

839 | In the nuclear reaction given by ( _{2} H e^{4}+_{7} N^{14} rightarrow_{1} H^{1}+X ) the nucleus ( x ) is A. nitrogen of mass 16 B. nitrogen of mass 17 c. oxygen of mass 16 D. oxygen of mass 17 | 12 |

840 | State the law of Radioactive disintegration | 12 |

841 | Half life of radioactive element depends upon A. amount of element present B. temperature c. pressure D. nature of element | 12 |

842 | Which of the following waste is present in coolant water from atomic reactors? A. Solid municipal waste B. Low-level radioactive waste c. High-level radioactive waste D. None of the above | 12 |

843 | Let ( m_{p} ) be the mass of proton, ( m_{n} ) the mass of a neutron, ( M_{1} ) the mass of a ( _{10}^{20} N e ) nucleus, and ( M_{2} ) the mass of a ( _{20}^{40} C a ) nucleus. Then This question has multiple correct options A. ( M_{2}=2 M_{1} ) В . ( M_{2}>2 M_{1} ) c. ( M_{2}<2 M_{1} ) D. ( M_{1}<10left(m_{p}+m_{p}right) ) | 12 |

844 | ( A gamma ) ray photon produces an electron positron pair. If the rest mass energy of electron is 0.51 Mev and the total kinetic energy of electron – positron pair is ( 0.78 M e V ) then the energy of ( gamma- ) ray photon is ( M e v ) is A . 0.78 в. 1.8 c. 1.28 D. 0.28 | 12 |

845 | A count rate-meter is used to measure the activity of a given sample. At one instant the meter shows 4750 counts per minute. Five minutes later it shows 2700 counts per minute. The decay constant of the sample is ( A cdot 0.565 min ^{-1} ) B. ( 0.452 mathrm{min}^{-1} ) c. ( 0.226 min ^{-1} ) D. ( 0.113 min ^{-1} ) | 12 |

846 | Best moderator for neutron is A. berillium oxide B. pure water c. heavy water D. graphite | 12 |

847 | A nucleus ( z X^{A} ) emits ( 9 alpha ) -particles and 5 ( p ) particle. The ration of total protons and neutrons in the final nucleus is: A ( frac{(Z-13)}{(A-Z-23)} ) B. ( frac{(Z-18)}{(A-36)} ) c. ( frac{(Z-23)}{(A-Z-8)} ) D. ( frac{(Z-13)}{(A-Z-13)} ) | 12 |

848 | Boron rods are used in nuclear reactor as A. moderator B. control rods c. coolant D. protective shield | 12 |

849 | The source emits only one type of radiation. For each type of radiation, ( boldsymbol{alpha}, boldsymbol{beta} ) and ( gamma, ) state whether or not is emitted, given reason for your answer in each case. | 12 |

850 | The fraction of atoms of radioactive element that decays in 6 days is ( 7 / 8 ) The fraction that decays in 10 days will be : A. ( 77 / 80 ) B. ( 71 / 80 ) c. ( 31 / 32 ) D. ( 15 / 16 ) | 12 |

851 | A radioactive substance of half life 69.3 days is kept in a container. The time in which ( 80 % ) of the substance will disintegrate will be A. 1.61 days B. 16.1days c. 161 days D. 1610 days | 12 |

852 | A beam of ultraviolet radiation having wavelength between ( 100 n m ) and ( 200 n m ) is incident on a sample of atomic hydrogen gas. Assuming that the atoms are in ground state, which wavelengths will have low intensity in the transmitted beam? A . ( 104 n m ) в. ( 103 n m ) c. ( 105 n m ) D. 100 nm | 12 |

853 | Isotones possess which of the following properties? A. They have different number of electrons B. They have same number of neutrons but different number of nucleons c. Both A and B D. None of the above | 12 |

854 | Substances which have identical chemical properties but differ in atomic weight are called. A. Isothermals B. Isotopes c. Isotropics D. Elementary particles | 12 |

855 | Which of the following is used in cancer treatment? ( mathbf{A} cdot frac{1331}{51} ) B . ( _{15}^{22} P ) ( mathrm{c} cdot_{27}^{60} mathrm{Co} ) ( mathrm{D} cdot_{1}^{2} mathrm{H} ) | 12 |

856 | Binding energy per nucleon for helium nucleus ( left(_{2}^{4} H eright) ) is ( 7.0 mathrm{MeV} . ) Find vallue of mass defect for helium nucleus. | 12 |

857 | A certain radioactive material can undergo three different types of decay, each with a different decay constant ( lambda, 2 lambda, ) and ( 3 lambda . ) Then, the effective decay constant ( lambda_{e f f} ) is equal to ( n lambda ). What is the value of n? | 12 |

858 | Find the accurate expressions. ( mathbf{A} cdot E=m c^{2} ) B . ( E=m / c^{2} ) ( mathbf{C} cdot M=E c^{2} ) D. All of the expressions are accurate. E ( cdot c=E m^{2} ) | 12 |

859 | What is meant by pair production and annihilation? | 12 |

860 | The elements ( A ) and ( B ) combine together to give two compounds ( A_{2} B_{3} ) and ( A B_{2} . ) The weight of 0.2 mole of ( A_{2} B_{3} ) is ( 26 g mathrm{m} ). The weight of 0.3 mole of ( A B_{2} ) is ( 24 mathrm{gm} . ) Then the atomic weights of ( A ) and ( B ) respectively. A. 15,20 B. 20,25 c. 20,30 D. 25,30 | 12 |

861 | The correct equation of nuclear fusion reaction is ( mathbf{A} cdot_{1} H^{1}+_{1} H^{1} rightarrow H_{2} ) ( mathbf{B} cdot_{1} H^{2}+_{1} H^{1} rightarrow_{2} H e^{4}+_{0} n^{1} ) ( mathbf{C} cdot_{1} H^{2}+_{1} H^{2} rightarrow_{2} H e^{4}+ )energy ( mathbf{D} cdot 2 H_{2}+3 H_{2} rightarrow 5 H_{2} ) | 12 |

862 | The activity of certain preparation decreases by ( 75 % ) after 7.0 days. Tha half life of the sample is [Take ( ln (0.4)= ) -0.916] A . 2.9 days B. 5.3 days c. 3.5 days D. 6 days | 12 |

863 | A nucleus of sodium- ( 21, frac{21}{11} N a, ) decays to form a new nucleus containing 10 protons and 11 neutrons. Which leptons are emitted from the | 12 |

864 | The ( frac{B . E}{A} ) ratio for deuteron and ( alpha ) particle are ( X_{1} ) and ( X_{2} ) respectively. The energy released in the fusion of deuteron into ( alpha ) -particle is ( mathbf{A} cdot 4left(X_{2}-X_{1}right) ) B ( cdot 2left(X_{2}-X_{1}right) ) ( mathbf{c} cdot 4left(X_{2}+X_{1}right) ) D. ( frac{X_{2}-X 1}{4} ) | 12 |

865 | Define curie. | 12 |

866 | 73. Samples of two radioactive nuclides, X and Y, each have equal activity A at time t = 0. X has a half-life of 24 years and Y a half-life of 16 years. The samples are mixed together. What will be the total activity of the mixture at t = 48 years? 1- -in me W | 12 |

867 | Free ( ^{238} boldsymbol{U} ) nuclei kept in a train emit alpha particles.When the train is stationary and a uranium nucleus decays, a passenger measures that the separation between the alpha particles and the recoiling nucleus becomes ( x, ) in ( t ) time after the decay. If a decay takes places, when the train is moving at a uniform speed ( v, ) the distance between the alpha particle and the recoiling nucleus at a time ( t ) after the decay, as measured by the passenger will be A ( . x+v t ) B. ( x-v t ) ( c ) D. depends on the directions of the train | 12 |

868 | Assertion Isotopes of an element can be separated by using a mass spectrometer. Reason Separation of isotopes is possible because of difference in electron number of isotopes. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

869 | Fusion reactions take lace at high temperature because A. atoms are ionized at high temperature B. molecules break up at high temperature C . nuclei break up at high temperature D. kinetic energy is high enough to overcome repulsion between nuclei | 12 |

870 | A radioactive nuclide is produced at the constant rate of ( ^{prime} boldsymbol{n}^{prime} ) per second (say, by bombarding a target with neutrons) The expected number’ ( N^{prime} ) of nuclei in existence ( t ) s after the number is ( N_{0} ) is given by A. ( N=N_{0} e^{-lambda t} ) B. ( N=frac{n}{lambda} N_{0} e^{-lambda} ) c. ( N=frac{n}{lambda}+left(N_{0}-frac{n}{lambda}right) e^{-lambda t} ) D. ( N=frac{n}{lambda}+left(N_{0}+frac{n}{lambda}right) e^{-lambda t} ) | 12 |

871 | In a Bainbridge mass spectrometer positive rays of the same element produce different traces. The traces correspond to: A. isotopes B. isobars c. isotones D. none of the above | 12 |

872 | The power obtained in a reactor using ( U^{235} ) disintegration is ( 1000 k W . ) The mass decay of ( U^{235} ) per hour is : A. 10 microgram B. 20 microgram c. 40 microgram D. 1 microgram | 12 |

873 | The sources of energy obtained in a nuclear reaction are : A. Mass defect B. Binding energy c. Fission D. Fusion E. All of these | 12 |

874 | For uranium nucleus how does its mass vary with volume? ( A cdot m propto V ) B. ( m propto 1 ) IN ( c cdot m propto ) ( D cdot m propto V^{2} ) | 12 |

875 | Two isotopes ( P ) and ( Q ) of atomic weight 10 and ( 20, ) respectively are mixed in equal amount by weight. After 20 days their weight ratio is found to be 1: 4 Isotope ( P ) has a half-life of 10 days. The half-life of isotope ( Q ) is A . zero B. 5 days c. 20 days D. infinite | 12 |

876 | Which of the following statement is correct? A. Alpha particles are singly ionised helium atoms B. Protons and neutrons have exactly the same mass C. Beta rays are same as cathode rays D. Gamma rays are high energy neutrons | 12 |

877 | Two samples ( A ) and ( B ) of same radioactive nuclide are prepared Sample A has twice the initial activity of sample B. For this situation, mark out the correct statement(s): This question has multiple correct options A. The half-lives of both the samples would be same B. The half-lives of the samples are different C. After each has passed through 5 half-lives, the ratio of activity of A to B is 2: D. After each has passed through 5 half-lives, ratio of activities of A to B is 64: | 12 |

878 | The stable nucleus that has a radius ( 1 / 3 ) that ( O s^{189} ) is ( mathbf{A} cdot_{3} L i^{7} ) B ( cdot_{2} mathrm{He}^{4} ) ( mathbf{c} cdot_{5} B^{10} ) ( mathrm{D} cdot_{6} C^{12} ) | 12 |

879 | Which of the following statement best describe Nuclear fusion reaction? A. two smaller nuclei are combined into a more massive nuclei B. the electrons are exchanged from one or more substances to produce a different substance, and the elements are the same in the products and reactants. C. the nucleus of a large atom is split into two or more fragments. D. the particles in the nucleus are changed, and one element is transformed into another element when particles in the nucleus are gained or lost. E. radiation is made | 12 |

880 | ( mathbf{4}_{mathbf{1}} boldsymbol{H}^{mathbf{1}} rightarrow_{mathbf{2}} boldsymbol{H} boldsymbol{e}^{mathbf{4}}+mathbf{2} boldsymbol{e}^{+}+mathbf{2} mathbf{6} boldsymbol{M} boldsymbol{e} boldsymbol{V} ) The above reaction represents A. Fusion B. Fission c. ( beta ) -decay D. ( gamma ) -decay | 12 |

881 | If a proton is completely converted into the energy, then the energy produced will be: A. ( 0.51 mathrm{MeV} ) B. 1.02 MeV c. ( 185 mathrm{MeV} ) D. 932 MeV | 12 |

882 | When a nucleus with atomic number ( z ) and mass number A undergoes a radioactive decay process A. both ( z ) and ( A ) will decrease if the process is ( alpha ) -decay B. Z will decrease but A will not change if the process is ( beta^{+}- ) decay c. z will increase but A will not change, if the process is ( beta^{-}- ) decay D. z and A will remain unchanged if the process is ( gamma ) decay | 12 |

883 | If the binding energy per nuclear in ( L i^{7} ) and ( H e^{4} ) nuclei are respectively ( mathbf{5 . 6 0} M e V ) and ( 7.06 M e V, ) then energy of reactor ( L i^{7}+P rightarrow 2_{2} H e^{4} ) is: A. ( 19.6 mathrm{MeV} ) B. ( 2.4 mathrm{MeV} ) c. ( 8.4 mathrm{MeV} ) D. ( 17.6 mathrm{MeV} ) | 12 |

884 | In a nuclear reactor, nuclear energy is converted into | 12 |

885 | Estimate the increase in wavelength in an average compton scattering process. ( mathbf{A} cdot 5 times 10^{-33} mathrm{m} ) B ( .5 times 10^{-31} mathrm{m} ) D. ( 2 times 10^{-31} mathrm{m} ) | 12 |

886 | Cadmium rods are used in a nuclear reactor A. To produce neutrons B. To speed up neutrons c. To absorb neutrons D. None of these | 12 |

887 | Which of the following has an equal number of neutrons and protons? A. Hydrogen B. Deuterium c. Fluorine D. Chlorine | 12 |

888 | Consider fusion of ( H e ) plasma. At what temperature fusion at a distance 2 fm is possible A ( .2 .23 times 10^{9} K ) В. ( 22.3 times 10^{9} K ) ( mathbf{c} cdot 2.23 times 10^{8} K ) D. none of these | 12 |

889 | Th – 230 undergoes a series of radioactive decay processes resulting in ( B i-214 ) being the final product. What was the sequence of the processes that occurred? ( mathbf{A} cdot alpha, alpha, alpha, g, beta ) в. ( alpha, alpha, alpha, alpha, beta ) ( mathbf{c} cdot alpha, alpha, beta, beta ) ( mathbf{D} cdot alpha, beta, beta, beta, gamma ) | 12 |

890 | A radioactive sample at any instant has its disintegration rate 5000 disintegrations per minute. After 5 minutes, the rate is 1250 disintegrations per minute. Then, the decay constant (per minute) is A. ( 0.4 ln 2 ) B. ( 0.2 ln 2 ) c. ( 0.1 ln 2 ) D. ( 0.8 ln 2 ) | 12 |

891 | In an endothermic reaction the binding energies of reactants and products are ( e_{1}, e_{2} ) respectively, then B ( cdot e_{1}=e_{2} ) ( mathbf{c} cdot e_{1}>e_{2} ) D. ( e_{1} geq e_{2} ) | 12 |

892 | The mean lives for ( alpha ) and ( beta ) decay of a radioactive substance are 1620 years and 405 years respectively. The time in which ( frac{3}{4} t h ) of the material will decay, if it simultaneously emits ( alpha ) and ( beta ) particles is A. 449 years B. 199 years ( c cdot alpha ) D. 99 years | 12 |

893 | The reaction that take place in nuclear reactor is: A. Nuclear fusion B. Nuclear fission c. controlled nuclear fission D. Double decomposition | 12 |

894 | The most stable nucleus should have: A. even number of proton and odd number of neutrons B. odd number of neutrons and odd number of protons C. even number of protons and even number of neutrons D. even number of neutrons and odd number of protons | 12 |

895 | A nucleus of lead ( P b_{82}^{314} ) emits two electrons’followed by an alpha particle. The resulting nucleus will have A. 82 protons and 128 neutrons B. 80 protons and 130 neutrons c. 82 protons and 130 neutrons D. 78 protons and 134 neutrons | 12 |

896 | 9. The intensity of gamma radiation from a given source is 1. On passing through 36 mm of lead, it is reduced to I/8. The thickness of lead which will reduce the intensity to 1/2 will be (a) 18 mm (b) 12 mm (c) 6 mm (d) 9 mm (AIEEE 2005) | 12 |

897 | One of the characteristics of nuclear reactions is that in their decayed or fused parts A. total mall number keeps on changing B. total charge number keeps on changing c. total charge number remains constant D. all the above | 12 |

898 | If the decay constants of two elements are in 1: 2 ratio, their half lives are in the ratio: A . 1: 2 B ( cdot 1^{2}: 2^{2} ) c. 2: 1 D. 4: 1 | 12 |

899 | The half life of a neutron is 800 sec. ( 10^{8} ) neutrons at a certain instant are projected from one space station towards another space station, situated ( 3200 mathrm{km} ) away, with a velocity ( 2000 mathrm{m} / mathrm{s} ) their velocity remains constant during the journey. How many neutrons reach the oyher station? A ( .50 times 10^{6} ) B . ( 25 times 10^{6} ) c. ( 80 times 10^{5} ) D. ( 25 times 10^{5} ) | 12 |

900 | In a hydrogen spectrum third line of Balmer’s series having wavelength ( lambda ) Find the binding energy of the ground state | 12 |

901 | The half life of a radioactive substance is 20 minutes. The approximate time interval ( left(mathrm{t}_{2}-mathrm{t}_{1}right) ) between the time ( mathrm{t}_{1} ) when ( frac{1}{3} ) of it had decayed and ( t_{2} ) when ( frac{2}{3} ) of it had decayed is : ( A cdot 7 min ) B. 14 min ( c .20 mathrm{min} ) D. 28 min | 12 |

902 | Which of the following is NOT an isotope of uranium? B ( cdot frac{235}{91} mathrm{U} ) ( mathrm{c} cdot_{92}^{239} mathrm{U} ) D. ( frac{235}{92} mathrm{U} ) E ( cdot frac{238}{92} mathrm{U} ) | 12 |

903 | The ratio ( r ) of the rate of production of neutrons from uranium nucleus to the rate of leakage of neutrons for sustained chain reaction is ( mathbf{A} cdot r>1 ) В. ( 1>r ) c. ( 1>r^{2} ) D. ( r^{2}=1 ) | 12 |

904 | Identify which of the following energy released when a large nucleus splits into smaller nuclei. A. nuclear energy B. thermal energy c. radiant energy D. sound E. potential energy | 12 |

905 | Radioactivity of an isotope falls to ( 1 / 8 ) of its original value in 48 days. What is its half-life period (in days)? A . 48 B . 16 ( c cdot 12 ) D. | 12 |

906 | order to calculate the binding energy per nucleon of an element ( _{z} X^{A}, ) given the actual mass of ( _{z} X^{A}(mathrm{M}), ) mass of proton ( left(boldsymbol{m}_{boldsymbol{p}}right) ) and mass of neutron ( left(boldsymbol{m}_{boldsymbol{n}}right) ) (All the values are given in atomic mass units) (a) Note the actual mass of the nucleus (M), number of nucleons in ( _{z} boldsymbol{X}^{boldsymbol{A}}, boldsymbol{m}_{boldsymbol{p}} ) and ( boldsymbol{m}_{boldsymbol{n}} ) (b) Calculate the mass defect of the given nucleus. (c) Find the number of protons and number of neutrons in the nucleus. (d) Determine the sum of the individual masses of constituents in ( _{z} boldsymbol{X}^{boldsymbol{A}} ) (e) Calculate the binding energy (B. E) of the nucleus. (f) Divide it with the number of nucleons present in the element to get binding energy per nucleon. A. a ed cb f B. a c d bef ( c cdot a c b d e f ) D. a d c be f | 12 |

907 | Among the following interactions, the one of least significance in nuclear physics is A. nuclear interaction B. gravitational interaction c. electrostatic interaction D. electromagnetic interaction | 12 |

908 | A radioactive substance has density ( rho ) volume ( V ) and decay constant ( lambda ). If the molecular weight of the substance is ( M, ) and Avogadro’s number is ( N_{a}, ) then the radioactivity of the substance after time ( ^{prime} boldsymbol{t}^{prime} ) is: ( ^{mathbf{A}} cdotleft(frac{lambda V rho N_{a}}{M}right)left(1-e^{lambda t}right) ) B. ( left(frac{t N_{a} V}{rho M}right) e^{lambda t / 2} ) c. ( frac{lambda N_{a}}{V rho M} e^{-lambda t} ) D. ( frac{lambda V rho N_{a} e^{-lambda t}}{M} ) | 12 |

909 | In the radioactive transformation ( z^{boldsymbol{X}}^{boldsymbol{A}} frac{boldsymbol{beta}^{-}}{boldsymbol{X}} boldsymbol{z}+mathbf{1} boldsymbol{X}_{mathbf{1}}^{boldsymbol{A}} ) ( z-1 X_{2}^{A-4} longrightarrow Z_{-3} X_{3}^{A-3} ) which are successively emitted radioactive radiations? A ( cdot beta^{-}, alpha, beta^{-} ) в. ( alpha, beta^{-}, beta^{-} ) ( mathrm{c} cdot beta^{-}, alpha, alpha ) D ( cdot alpha, beta^{-}, alpha ) | 12 |

910 | A hypothetical radioactive nucleus decays according to the following series ( mathrm{z}_{2} boldsymbol{A}^{180} underline{boldsymbol{alpha}} boldsymbol{A}_{1} stackrel{boldsymbol{beta}^{-}}{longrightarrow} boldsymbol{A}_{2} underline{boldsymbol{alpha}} boldsymbol{A}_{3} underline{boldsymbol{Upsilon}} boldsymbol{A}_{4} ) If the mass number and atomic number of A are respectively 180 and 72 . then the atomic number and mass number of A will respectively be: ( mathbf{A} cdot 69,171 ) B. 70,172 c. 68,172 D. 69,172 | 12 |

911 | Moderator is used in nuclear reactor for: A. slowing neutrons B. accelerating neutrons c. stopping neutrons D. heating the neutrons | 12 |

912 | Assertion Neutrons penetrate matter more readily as compared to protons. Reason Neutrons are slightly more massive than protons. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

913 | What is the essential difference between the working of a nuclear reactor and that of a fission bomb? | 12 |

914 | Arrange the three natural radiations in decreasing order of penetration A. alpha, beta, and gamma B. beta, gamma, and alpha c. gamma, alpha, and beta D. gamma, beta, and alpha E. beta, alpha, and gamma | 12 |

915 | Compare the penetrating powers of ( alpha, beta ) and ( gamma ) – radiations. A ( cdot alpha>beta>gamma ) v в. ( alpha<betagamma>beta ) D. ( alpha<gamma<beta ) | 12 |

916 | The rest energy of electron or positron is ( mathbf{A} cdot 0.51 mathrm{MeV} ) B. 1 MeV c. ( 1.02 mathrm{MeV} ) D. 1.5 Mev | 12 |

917 | ( A ) and ( B ) are isotopes. ( B ) and ( C ) are isobars. All three are radioactive. A. ( A, B ) and ( C ) must belong to the same element B. ( A, B ) and ( C ) may belong to the same element c. It is possible that ( A ) will change to ( B ) through a radioactive-decay process D. It is possible that ( B ) will change to ( C ) through a radio active -decay process | 12 |

918 | (a) State the names of two elements that produce nuclear energy. (b) What are high and low tides? | 12 |

919 | If the decay constant of radium is ( 4.28 times 10^{-4} ) per year, then its half life will be approximately be A. 1240 years B. 1620 years c. 2000 years D. 2260 years | 12 |

920 | The velocity of a body of rest mass ( m_{o} ) is ( frac{sqrt{3}}{2} c(text { where } c ) is the velocity of light in vacuum). The mass of this body is : ( ^{mathbf{A}} cdotleft(frac{sqrt{3}}{2}right) m_{o} ) B ( cdotleft(frac{1}{2}right) m_{o} ) ( mathrm{c} cdot 3 m_{0} ) D. ( 2 m_{o} ) | 12 |

921 | Atomic masses of two isobars ( _{29}^{64} C u ) and ( _{30}^{64} Z n ) are ( 63.9298 u ) and ( 63.9292 u ) respectively. It can be concluded from this data that A. both the isobars are stable B. ( 64 Z n ) is radioactive, decaying to ( ^{64} C u ) through ( beta- ) decay C. ( ^{64} C u ) is radioactive, decaying to ( ^{64} Z n ) through ( beta- ) decay D. ( ^{64} C u ) is radioactive, decaying to ( ^{64} Z n ) through ( gamma ) decay | 12 |

922 | Why nuclei invariably have mass less than the sum of the masses of the individual nucleons in them? | 12 |

923 | The term ( B W R ) stands for A. Bureau of Workers Rights B. Boiling Water Reactor c. Bilateral Water Reactor D. Bureau of Waste Research | 12 |

924 | The energy emitted per second by sun is approximately A . ( 3.8 times 10^{26} ) Joule B. ( 3.8 times 10^{14} ) Joule c. ( 3.8 times 10^{12} ) Joule D. ( 3.8 times 10^{-26} ) Joule | 12 |

925 | ILLUSTRATION 30.9 A 50.0 g sample of carbon is taken from the pelvis bone of a skeleton and is found to have a ‘C decay rate of 200.0 decays min-‘. It is known that carbon from a living organism has a decay rate of decays/ming and that 14C has a half-life of 5730 year = 3.01 x 10 min. Find the age of the skeleton. | 12 |

926 | At time ( t=0, N_{1} ) nuclei of decay constant ( lambda_{1} ) and ( N_{2} ) nuclei of decay constant ( lambda_{2} ) are mixed. The decay rate of mixture is ( mathbf{A} cdot N_{1} N_{2} e^{-left(lambda_{1}+lambda_{2}right) t} ) B. ( -left(frac{N_{1}}{N_{2}}right) e^{-left(lambda_{1}+lambda_{2}right) t} ) C. ( -left(N_{1} lambda_{1} e^{-lambda_{1} t}+N_{1} lambda_{2} e^{-lambda_{2} t}right) ) D. ( -N_{1} lambda_{1} N_{2} lambda_{2} e^{left(-lambda_{1}+lambda_{2}right) t} ) | 12 |

927 | If the half life of a radioactive material is 100 days then its half life after 10 days will become A. 50 days B. 200 days c. 400 days D. 100 days | 12 |

928 | If the half-lives of a radioactive element for ( alpha ) – decay and ( beta ) – decay are 4 years and 12 years respectively. What percent would its total activity be of its initial activity after 12 years? A . 50 B. 25 c. 12.5 D. 6.25 | 12 |

929 | Which of the following is/are source(s) of internal radiations? A. Solar radiations B. Radioactive substances present inside the body c. Beta radiations D. Naturally occurring radioactive substances | 12 |

930 | Radioactivity is a phenomenon. A. nuclear B. elustronic c. atomic D. all of the above | 12 |

931 | ( P u^{239} ) and ( U^{238} ) are respectively: A . fertile material, artificial fissile material B. artificial fissile material, fertile material c. both artificial fissile materials D. both fertile materials | 12 |

932 | The reaction, ( _{92}^{235} U+_{0}^{1} n longrightarrow_{56}^{140} B a+_{36}^{93} ) ( K r+3 ) represents: A. artificial radioactivity B. nuclear fission c. nuclear fusion D. none of the above | 12 |

933 | Nuclear energy may become an important source of energy in the future. Which one of the following statements about nuclear energy is NOT true? A. Large amounts of energy are produced by a smal mass of fuel B. Nuclear energy has no harmful effects c. Nuclear energy produces heat on the sunn D. Uranium is an important fuel for nuclear energy | 12 |

934 | The nucleus ( ^{23} N e ) decays by ( beta- ) emission into the nucleus ( ^{23} N a ). Write down the ( beta- ) decay equation and determine the maximum kinetic energy of the electrons emitted. Given, ( boldsymbol{m}left(_{mathbf{1 0}}^{23} boldsymbol{N} boldsymbol{e}right)=mathbf{2 2 . 9 9 4 4 6 6 a m u} ) and ( boldsymbol{m}left(_{11}^{23} boldsymbol{N a}right)=22.989770 a m u . ) Ignore the mass of antineutrino ( (overline{boldsymbol{v}}): ) | 12 |

935 | Give a reason for your answer. | 12 |

936 | The half-life of that radioactive substance, which reduces to ( 1 / 64 ) of its initial value in 15 hours, will be A. 5 hours B. 2 hours c. 2.5 hours D. 4 hours | 12 |

937 | Calculate the neutron separation energy from the following data. ( boldsymbol{m}left(_{20}^{40} boldsymbol{C a}right)=mathbf{3 9 . 9 6 2 5 9 1} boldsymbol{u} ) ( boldsymbol{m}left(_{20}^{41} boldsymbol{C a}right)=mathbf{4 0 . 9 6 2 2 7 8} boldsymbol{u} ) ( boldsymbol{m}_{n}=mathbf{1 . 0 0 8 6 5} ) ( mathbf{1} boldsymbol{u}=mathbf{9 3 1 . 5} boldsymbol{M} e boldsymbol{V} / boldsymbol{C}^{2} ) ( mathbf{A} cdot 7.57 M e V ) В. ( 8.36 mathrm{MeV} ) c. 9.12 MeV D. 9.56 MeV | 12 |

938 | A radioactive element ( X ) converts into another stable element ( Y ). Half-life of ( boldsymbol{X} ) is 2 ( h ). Initially, only ( X ) is present. After time ( t, ) the ratio of atoms of ( X ) and ( Y ) is found to be ( 1: 4 . ) Then ( t ) in hours is A . 2 B. 4 c. between 4 and 6 D. 6 | 12 |

939 | In a hypothetical star,two carbon nuclei fuse to form magnesium.The reaction is:(take :1amu ( left.=mathbf{9 3 1} text { Me } boldsymbol{V} / mathbf{c}^{mathbf{2}}right) ) ( ^{12} boldsymbol{C}+^{12} boldsymbol{C} rightarrow^{24} boldsymbol{M} boldsymbol{g} ) The energy released per carbon nuclei is: (Mass of ( left.^{24} M g=23.985 a m uright) ) A. 13.965 MeV В. 11.12 Ме ( V ) c. 6.982 MeV D. 10.12 MeV | 12 |

940 | toppr Q Type your question can emit a ( beta ) particle ( left(beta_{1}right) ) and come to ground state by either emitting one ( gamma ) ray ( left(gamma_{1}right) ) or emitting two ( gamma ) rays ( left(gamma_{3} & gamma_{4}right) ) (ii) it can emit one ( beta ) particle ( left(beta_{2}right) ) and come to ground state by emitting ( gamma_{2} ) ray. Atomic masses : ( ^{198} A u=197.9682 ) a.m.u. ( ^{198} boldsymbol{H} boldsymbol{g}=mathbf{1 9 7 . 9 6 6 2} ) amu ( , 1 ) amu ( = ) ( 930 M e V / c^{2} ) The energy levels of the nucleus are shown in figure. What is the maximum kinetic energy of emitted ( beta_{2} ) particles? A. ( 1.44 mathrm{MeV} ) в. ( 0.59 mathrm{MeV} ) c. ( 1.86 mathrm{MeV} ) D. ( 1.46 M ) | 12 |

941 | Why high temperature is required for Nuclear fusion? A. All nuclear reactions absorb heat B. The particles can not come together unless they are moving rapidly c. The binding energy must be supplied from an external source D. The mass defect must be supplied | 12 |

942 | For the following nuclear disintegration process ( _{92}^{238} boldsymbol{U} rightarrow_{82}^{206} boldsymbol{P b}+boldsymbol{x}left[_{2}^{4} boldsymbol{H} eright]+left[_{-2}^{0} boldsymbol{e}right] ) then value of ( x ) is ( mathbf{A} cdot mathbf{8} ) B. 6 ( c cdot 4 ) D. 10 | 12 |

943 | The nuclear reactor at Kaiga is a : A. research reactor B. fusion reactor c. breedor reactor D. power reactor | 12 |

944 | Which of the following reactions is impossible? ( mathbf{A} cdot_{2} mathrm{He}^{4}+_{4} mathrm{Be}^{9}=_{0} mathrm{n}^{1}+_{6} mathrm{C}^{12} ) ( mathbf{B} cdot_{2} mathrm{He}^{4}+_{7} mathrm{N}^{14}=_{1} mathrm{H}^{1}+_{8} mathrm{O}^{17} ) ( mathbf{C} cdot 4left(_{1} mathrm{H}^{1}right)=_{2} mathrm{He}^{4}+2left(_{1} mathrm{e}^{0}right) ) ( mathbf{D} cdot_{3} mathrm{Li}^{4}+_{1} mathrm{H}^{1}=_{4} mathrm{Be}^{8} ) | 12 |

945 | Hydrogen bomb is based on A. thermochemical reaction B. nuclear fission c. nuclear fusion D. none of these | 12 |

946 | Assertion Two protons and two neutrons are each separated by a distance of ( mathbf{r}=mathbf{1 0}^{-14} mathbf{m} ) which is the size of the nucleus. Hence the force between two neutrons will be greatest. Reason At distances of the order of ( 10^{-14} mathrm{m} ) neutrons and protons exert very strong attractive forces on each other and this force does not depend on the charge. A. Statement l is True and Statement 2 is True and is a correct explanation of Statement 1 B. Statement lis True and Statement 2 is True but not a correct explanation of Statement c. statement lis True and Statement 2 is False D. Statement lis False and Statement 2 is True | 12 |

947 | Binding energy per nucleon versus mass number curve for nuclei is shown in the figure. ( A, B, C ) and ( D ) are four muclei indicated on the curve. The process that would release energy is he process that ( mathbf{A} cdot C rightarrow 2 D ) B . ( A rightarrow C+D ) ( mathbf{c} cdot A rightarrow 2 C ) D. ( B rightarrow C+D ) | 12 |

948 | The radioactivity of a sample is ( R_{1} ) at a time ( T_{1} ) and ( R_{2} ) at a time ( T_{2} . ) If the half- life of the specimen is ( T, ) the number of atoms that have disintegrated in the time ( T_{2}-T_{1} ) is proportional to A ( cdot T_{2}-T_{1} alphaleft(R_{1}-R_{2}right) T ) В ( cdotleft(R_{1}-R_{2}right) ) c. ( left(R_{1}-R_{2}right) / T ) D ( cdotleft(R_{1}-R_{2}right) T ) | 12 |

949 | A container is filled with a radioactive substance for which the half-life is 2 days. A week later, when the container is opened, it contains ( 5 g ) of the substance. Approximately how may grams of the substances were initially placed in the container? A . 40 B. 60 c. 80 D. 100 | 12 |

950 | The half life of ( ^{58} ) Co is 72 days. Its average life is: A. 102.9 days B. 103.9 days c. 104.9 days D. 105.9 days | 12 |

951 | If ( n_{t}, ) number of radio atoms are present at time ( t, ) the following expression will be a constant A ( cdot frac{n_{t}}{t} ) в. ( ln frac{n_{t}}{t} ) c. ( frac{d}{d t}left(ln n_{t}right) ) D. ( t cdot n_{t} ) | 12 |

952 | If the radius of a nucleus ( ^{256} X ) is 8 fermi, then the radius of ( ^{4} ) He nucleus will be: A. 16 fermi B. 2 fermi c. 32 fermi D. 4 fermi | 12 |

953 | Specific heat and equivalent wt. of a metal are ( =0.057 ) cal ( g^{-1} ) and 38.24 respectively. It’s exact atomic weight is? A . ( 114.72 g ) в. ( 38.297 g ) c. ( 110.9 g ) D. uncertain | 12 |

954 | Calculate the number of neutrons produced along with ( _{54}^{139} X e ) and ( _{38}^{94} S r ) from the absorption of a slow neutron by ( 235 boldsymbol{U} ) ( . ) | 12 |

955 | When an atom undergoes ( beta ) -decay, its atomic number A. Does not change B. Increases by 1 c. Decreases by 1 D. Increases by 2 | 12 |

956 | The mass defect per nucleon is called A. binding energy B. packing fraction c. ionisation energy D. excitation energy | 12 |

957 | The binding energies of the atoms of elements ( boldsymbol{P} ) and ( boldsymbol{Q} ) are ( boldsymbol{E}_{boldsymbol{p}} ) and ( boldsymbol{E}_{Q} ) respectively. Three atoms of element ( boldsymbol{Q} ) fuse to form one atom of element ( P . ) In this process, the energy released is ( e ) The correct relation between ( boldsymbol{E}_{boldsymbol{P}}, boldsymbol{E}_{boldsymbol{Q}} ) and ( e ) will be ( mathbf{A} cdot E_{Q}=3 E_{P}+e ) B . ( E_{Q}=3 E_{P}-e ) ( mathbf{c} cdot E_{P}=3 E_{Q}+e ) D. ( E_{P}=3 E_{Q}-e ) | 12 |

958 | The decay constant of the parent nuclide in uranium series is / lambda. Then the decay constant for the stable end product of the series will be? A. ( lambda / 238 ) B. ( lambda / 206 ) ( c cdot lambda / 208 ) D. zero | 12 |

959 | Radioactivity of a sample ( (Z=22) ) decreases ( 90 % ) after 10 yr. What will be the half-life of the sample? A . 5 yr B. 2 yr ( c cdot 3 y r ) D. 10 yr | 12 |

960 | The number of ( alpha ) and ( beta ) -particles emitted in the conversion of ( g_{0} T h^{232} ) to ( 82 P b^{208} ) are : ( mathbf{A} cdot 6,4 ) в. 4,6 ( c cdot 8,6 ) D. 6,8 | 12 |

961 | If the nuclei of masses ( X ) and ( Y ) are fused together to form a nucleus of mass ( m ) and some energy is released, then A. ( X+Y=m ) B. ( X+Ym ) D. ( X-Y=m ) | 12 |

962 | Which quantity remains same in isobars? A. Number of neutrons B. Number of protons c. Mass number D. All of the above | 12 |

963 | The initial number of atoms of a radioactive element with half life 100 days, is ( 9.6 times 10^{26} . ) The number of atoms remaining undecayed after 500 days, will be A ( cdot 9.6 times 10^{25} ) B . ( 3.84 times 10^{25} ) ( mathrm{c} cdot 3 times 10^{25} ) D. ( 19.2 times 10^{25} ) | 12 |

964 | An isotope decays to ( 1 / 16^{text {th }} ) of its mass in ( 1 h . ) What is the half-life period of the isotopes? A . 15 min B. 30 min ( c .12 ) min D. 10 min | 12 |

965 | What are isobars? | 12 |

966 | Energy equivalent of 10 amu is A. 93.15 Mev B. 931.5 Mev C. 9315 Mev D. 9315 Joules | 12 |

967 | What is the exchange particle for strong nuclear interaction? A. neutrino B. positron c. ( pi ) meson D. ( alpha ) – particle | 12 |

968 | For Uranium nucleus, how does its mass vary with volume? ( A cdot m propto V ) в. ( m propto 1 / V ) ( mathbf{c} cdot m propto sqrt{V} ) D ( cdot m propto V^{2} ) | 12 |

969 | The nuclear reaction that takes place in a nuclear reactor is A. controlled fission reaction B. uncontrolled fission reaction c. nuclear fusion reaction D. none of the above | 12 |

970 | The fraction of a radioactive sample that will decay during half of its half life period is A ( cdot frac{1}{sqrt{2}} ) в. ( frac{1}{sqrt{2}-1} ) c. ( frac{sqrt{2}-1}{sqrt{2}} ) D. ( frac{1}{2} ) | 12 |

971 | Energy in the sun is due to A. Fossil fuels B. Radioactivity c. Fission D. Fusion | 12 |

972 | During a ( beta^{-} ) decay which of the following statements are correct? A. The daughter nucleus has one proton less than the parent nucleus B. The daughter nucleus has one proton more than the parent nucleus c. An electron which is already present within the nucleus is rejected D. A neutron in the nucleus decays emitting an electron | 12 |

973 | A nuclear fission is given below ( A^{240} rightarrow B^{100}+C^{140}+Q(text {energy}) ) Let binding energy per nucleon ( A, B ) and ( mathrm{C} ) is ( 7.6 mathrm{MeV}, 8.1 mathrm{MeV} ) and ( 8.1 mathrm{MeV} ) respectively. Value of ( Q ) is : A. 20 Mev B. 220 MeV c. 120 Mev D. 240 Mev | 12 |

974 | Explain the process of release of energy in the installation at Chernobyl. | 12 |

975 | Naturally occurring argon (Ar) consists of three isotopes the atoms of which occur in the abundances as given in the table The atomic weight of argon is: Isotopes Abundance ( ^{36} A r ) 0.34% ( ^{38} A r ) 0.07% ( begin{array}{ll}40 & text { 99.59% }end{array} ) A. 38.45 u в. 37.20 c. 39.98 и D. 40.98 u | 12 |

976 | Ip experiment on scattering ot ( boldsymbol{alpha} ) -particles by a thin foil of gold, draw the trajectory of ( alpha ) -particles in the coulomb field of target nucleus. Explain briefly how one gets the information on the size of the nucleus from this study. From the relation ( boldsymbol{R}=boldsymbol{R}_{0} boldsymbol{A}^{1 / 3}, ) where ( boldsymbol{R}_{0} ) is constant and ( A ) is the mass number of the nucleus, show that nuclear matter density is independent of ( mathbf{A} ) OR Distinguish between nuclear fission and fusion. Show how in both these | 12 |

977 | Assertion A nucleus having enrgy ( E_{1} ) decays by ( beta ) emission to daughter nucleus having energy ( E_{2} ) but the ( beta ) -rays are emitted with a continuous energy spectrum having end point energy ( boldsymbol{E}_{mathbf{1}}-boldsymbol{E}_{mathbf{2}} ) Reason To conserve energy and moment in ( boldsymbol{beta} ) decays at least three particles must take part in the transformation. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

978 | In a given reaction ( z^{boldsymbol{A}^{A}} longrightarrow z_{+1} boldsymbol{Y}^{boldsymbol{A}} longrightarrow z_{-1} ) ( boldsymbol{K}^{boldsymbol{A}-boldsymbol{4}} longrightarrow boldsymbol{z}-mathbf{1} boldsymbol{K}^{boldsymbol{A}-boldsymbol{4}} ) Radioactive radiations are emitted in the sequence of ( mathbf{A} cdot alpha, beta, gamma ) в. ( gamma, alpha, beta ) ( mathbf{c} cdot beta, alpha, gamma ) D. ( gamma, beta, alpha ), | 12 |

979 | How much energy is released when a ( mathrm{s} mathrm{O}^{16} ) nucleus is completely converted into energy? The binding energy per nucleon of ( _{8} O^{16} ) | 12 |

980 | Nuclei A and B convert into a stable nucleus C. Nucleus A is converted into C by emitting ( 2 alpha- ) particles and ( 3 beta- ) particles. Nucleus B is converted into ( C ) by emitting one ( alpha- ) particle and ( 5 beta- ) particles. At time ( t=0, ) nuclei of A are ( 4 N_{0} ) and nuclei of ( B ) are ( N_{0} . ) Initially, number of nuclei of ( C ) are zero. Half-life of ( A ) (into conversion of ( C ) ) is 1 min and that of ( mathrm{B} ) is 2 min. Find the time (in minutes) at which rate of disintegration of ( A ) and ( B ) are equal | 12 |

981 | The most penetrating atom smashing particle is A. neutron B. proton c. alpha particle D. deuteron | 12 |

982 | A certain radioactive material is known to decay at a rate proportional to the amount present. Initially there is ( 50 mathrm{kg} ) of thematerial present and after two hours it is observed that themateria has lost ( 10 % ) of its original mass, then the A ( cdot ) mass of the material after four hours is ( 50left(frac{9}{10}right)^{2} ) B. mass of the material after four hours is ( 50 . e^{-0.51 n 9} ) c. time at which the material has decayed to half of its initial mass (in hours) is ( frac{left(ell n frac{1}{2}right)}{left(-frac{1}{2} ell n 0.9right)} ) D. time at which the material has decayed to half of its initial mass (in hours) is ( frac{2 ln frac{1}{2}}{ln 0.99} ) | 12 |

983 | Which of the following is a best nuclear fuel? A. Thorium 236 B. Plutonium 239 c. Uranium 236 D. Neptunium 239 | 12 |

984 | If ( M_{O} ) is the mass of an oxygen isotope ( mathrm{s} boldsymbol{O}^{17}, boldsymbol{M}_{boldsymbol{p}} ) and ( boldsymbol{M}_{boldsymbol{n}} ) are the masses of a proton and a neutron, respectively, the nuclear binding energy of the isotope is A. ( M_{O} c^{2} ) B. ( left(M_{O}-17 M_{n}right) c^{2} ) ( mathbf{c} cdotleft(M_{O}-8 M_{p}right) c^{2} ) D. ( left(8 M_{p}+9 M_{n}-M_{O}right) c^{2} ) | 12 |

985 | Which of the following were released during accidental leakage in Chernobyl, the three-mile island? A . Low-level radiations B. Intermediate level radiation c. High level radiation D. No radiations were released | 12 |

986 | The activity of a radioactive element decreases to one-third of the origina activity ( A_{0} ) in a period of 9 years. After ( a ) further lapse of 9years, its activity will be ( A cdot A_{0} ) B. ( frac{2}{3} A_{0} ) c. ( frac{A_{0}}{9} ) D. ( frac{A_{0}}{6} ) | 12 |

987 | In a nuclear reactor, it is desirable to use reactor core in the form of A. cubical or cylindrical B. cubical or spherical c. cylindrical or spherical D. spherical | 12 |

988 | Which of the following is the best nuclear fuel? A ( cdot U^{23} ) B. ( P u^{23} ) C. ( N p^{239} ) D. ( T h^{236} ) | 12 |

989 | The radius of ( _{13}^{27} ) Al is 3.6 Fermi. Find the radius of ( _{52}^{125} mathrm{Te} ) A. 6 Fermi B. 8 Fermi c. 4 fermi D. 5 Fermi | 12 |

990 | Assertion For nuclear reactor, it is desirable to have (Multiplication Factor) ( k=1 ) Reason Sustained chain reaction occur at this critical condition. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect | 12 |

991 | Which word equation represents ( boldsymbol{beta}^{+} ) decay? A. Proton ( rightarrow ) neutron ( + ) electron ( + ) electron antineutrino B. Proton ( rightarrow ) neutron ( + ) electron ( + ) electron neutrino c. Proton ( rightarrow ) neutron ( + ) positron ( + ) electron antineutrino D. Proton ( rightarrow ) neutron ( + ) positron ( + ) electron neutrino | 12 |

992 | Which weapons among the following, though, would produce far less radioactive fallout than current designs, although they would release huge numbers of neutrons? A. Pure fission weapons B. Boosted fission weapons c. Pure fusion weapons D. None of the above | 12 |

993 | A radioactive substance X decays into another radioactive substance Y. Initially, only ( X ) was present. ( lambda_{x} ) and ( lambda_{y} ) are the disintegration constants of ( mathbf{X} ) | 12 |

994 | A radioactive sample contains two nucleoids ( A ) and ( B ) having decay constant ( lambda h r^{-1} ) and ( 2 lambda h r^{-1} . ) Initially ( 25 % ) of the decay comes from ( A ). The number of hours it will take before ( 75 % ) of the total decay comes from ( A ) is ( n ) ( (operatorname{take} lambda=ln 3) . ) Find ( n ) | 12 |

995 | Boron rods in a nuclear reactor are used to A. absorb excess neutrons B. absorb alpha particle c. slow down the reaction D. speed up the reaction | 12 |

996 | Two radio active elements ( X ) and ( Y ) have half lives of 50 minutes and 100 minutes respectively. Samples of ( X ) and initially contain equal number of atoms. After 200 minutes, the ratio of number of atoms of X unchanged to that of Y is A .4 B . 2 c. ( 1 / 2 ) D. ( 1 / 4 ) | 12 |

997 | A radioactive sample has ( 8.0 times 10^{18} ) active nuclei at a certain instant. How many of these nuclei will still be in the active state after two half-lives (in ( left.times 10^{18}right) ? ) | 12 |

998 | A radioactive substance after 48 days remains ( 25 % ) of initial. Find disintegration constant A ( cdot 2.89 times 10^{-2} T^{-1} ) В. ( 3.89 times 10^{-3} T^{-1} ) c. ( 4.89 times 10^{-2} T^{-1} ) D. none of these | 12 |

999 | The binding energy per nucleon of ( _{8} O^{16} ) is ( 7.97 M e V ) and that of ( _{8} O^{17} ) is ( 7.75 M e V . ) The energy required to remove one neutron from ( _{8} O^{17} ) is ( M e V ) A . 3.62 в. 3.52 c. 4.23 D. 7.86 | 12 |

1000 | Explain ( boldsymbol{E}=boldsymbol{m} boldsymbol{c}^{2} ) | 12 |

1001 | The energy equivalent to a substance of mass ( 1 mathrm{g} ) is? A ( cdot 18 times 10^{13} ) 」 В. ( 9 times 10^{13} ) j C ( .18 times 10^{6} mathrm{J} ) D. ( 9 times 10^{6} ), | 12 |

1002 | Two protons and two neutrons combine to form a nucleus of ( _{2} H e^{4} . ) Find the energy released during the process. Take masses of proton, neutron and helium nuclues as ( mathbf{1 . 0 0 7 u}, mathbf{1 . 0 0 9 u}, mathbf{4 . 0 0 2 u} ) respectively B. 84.67 MeV c. 94.82 Mev D. 24.12 Mev | 12 |

1003 | Which of the following is an example of nuclear fusion reaction? ( mathbf{A} cdot underset{90}{233} T H+_{0}^{1} n rightarrow_{90}^{234} T H ) B . ( _{48}^{13} mathrm{Cd}+_{0}^{1} n rightarrow_{48}^{114} mathrm{Cd}+gamma-mathrm{ray} ) ( mathbf{c} cdot_{i H}^{3} H+_{1}^{1} H rightarrow_{2}^{4} H e ) D ( cdot frac{239}{92} U rightarrow_{93}^{239} N p+_{-1}^{0} e ) | 12 |

1004 | What precautions should be taken against nuclear radiations? A. The radioactive elements should be kept in containers made up of thick lead walls. B. The people working in the plants should wear special jackets and gloves made of lead linings. C. The handling of the plants should be carried out from a distance. D. All of the above. | 12 |

1005 | A disadvantage of nuclear power is – A. it produces carbon dioxide which is responsible for global warming B. it produces toxic waste C . it affects the ozone layer D. it requires large amounts of fuel to produce a small amount of energy | 12 |

1006 | ( alpha ) and ( beta ) – particles emitted when uranium nucleus ( _{92} U^{238} ) decay to ( 82 P b^{214} ) are A. ( 6-alpha ) particles and ( 2-beta ) particles B. 4 ( alpha ) – particles and 2 ( beta ) particles c. ( 2-alpha ) particles and ( 6 beta ) particles D. 2 ( alpha ) -particles and 4 ( beta ) -particles | 12 |

1007 | State two safety measures to be taken while establishing a nuclear power plant. A. Use uranium rod and inside environment is not shielded B. Use uranium rod and inside environment should be shielded c. Use copper rod and inside environment is not shielded D. None of the above | 12 |

1008 | What is the importance of moderator in a nuclear reactor? A. Moderator controls the flow of water inlet B. Controls the nuclear fission by absorbing the excess neutrons c. controls the nuclear fission by slowing down the neutrons. D. None of these | 12 |

1009 | A newly prepared radioactive nuclide has a decay constant ( lambda ) of ( 10^{-6} s^{-1} ) What is the approximate half-life of the nuclide? A . 4 B. 1 day c. 8 week D. 12 month | 12 |

1010 | Energy released in the nuclear fusion reaction is : ( _{1} mathbf{H}^{2}+_{1} mathbf{H}^{3} rightarrow_{2} mathbf{H} mathbf{e}^{4}+_{0} mathbf{n}^{1} ) Atomic mass of some species are given below. ( _{1} mathbf{H}^{2}=mathbf{2 . 0 1 4},_{1} mathbf{H}^{3}=mathbf{3 . 0 1 6} ) ( _{2} mathbf{H e}^{4}=mathbf{4 . 0 0 3},_{0} mathbf{n}^{1}=mathbf{1 . 0 0 9} mathbf{a m u} ) A . ( 8.30 mathrm{eV} ) B. ( 16.758 mathrm{MeV} ) c. ( 500 mathrm{J} ) D. ( 4 times 10^{6} ) kcal | 12 |

1011 | 1 Curie is: A. Activity of ( 1 g ) of Uranium B. 1 disintegration / second C ( .3 .7 times 10^{10} ) becquerel D. ( 1.6 times 10^{12} ) disintegration / second | 12 |

1012 | The existence of isotopes is due to the presence of different number of A. electrons B. protons c. neutrons D. atoms | 12 |

1013 | A chlorine atom whose nucleus contains 17 protons and 20 neutrons. Find out the composition of the nucleus of an isotope of chlorine? A. 20 protons, 17 neutrons B. 19 protons, 18 neutrons c. 18 protons, 18 neutrons D. 17 protons, 19 neutrons E. 16 protons, 20 neutrons | 12 |

1014 | In an atomic explosion, a temperature of about 10 million degrees is developed at the moment of explosion. The wavelengths of light corning from the hot region of the atomic explosion lie in the A . Ultraviolet region B. Visible region c. Infrared region D. x-ray region | 12 |

1015 | Assertion (A): Fragments produced in the fission of ( U^{235} ) are radioactive Reason (R) : The fragments have abnormally high proton to neutron ratio A. Both A and R are true and R is correct explanation of A B. Both A and R are true and R is not correct explanation of c. ( A ) is true but ( R ) is false D. A is false but R is true | 12 |

1016 | Fill up the blanks. The lightest isotope is | 12 |

1017 | Results of calculations for four different designs of a fusion reactor using D-D reaction are given below.Which of these is most promising based on Lawson criterion? A. deuteron density ( =2.0 times 10^{12} mathrm{cm}^{-3} ), confinement time ( =5.0 times 10^{-3} mathrm{s} ) B. deuteron density ( =8.0 times 10^{14} mathrm{cm}^{-3} ), confinement time ( =9.0 times 10^{-1} mathrm{s} ) C. deuteron density ( =4.0 times 10^{23} mathrm{cm}^{-3}, ) confinement time ( =1.0 times 10^{-11} mathrm{s} ) D. deuteron density ( =1.0 times 10^{24} mathrm{cm}^{-3} ), confinement time [ =4.0 times 10^{-12} mathrm{s} ] | 12 |

1018 | The binding energies per nucleon for deuterium and helium are ( 1.1 mathrm{MeV} ) and ( 7.0 mathrm{MeV} ) respectively. How much amount energy, in joules, will be liberated when ( 10^{6} ) deuterons take part in the reaction. | 12 |

1019 | If it is assumed that ( _{92}^{235} U ) decays only by emitting ( alpha- ) and ( beta ) -particles, the possible product of the decay is A ( cdot frac{225}{89} mathrm{Ac} ) B . ( frac{297}{A c} ) ( mathbf{C} cdot_{89}^{230} A c ) D・ ( _{89}^{23} A C ) | 12 |

1020 | The energy released during the fission of ( 1 mathrm{kg} ) of uranium: A ( .9 times 10^{20} ) ergs B. ( 9.0 times 10^{10} ) ergs c. ( 9.0 times 10^{18} ) ergs D. ( 9.0 times 10^{8} ) ergs | 12 |

1021 | The rest energy involved in a mass of one atomic mass unit is ( mathrm{eV} ) A. ( 931 mathrm{MeV} ) B. 1.6 ev ( mathrm{c} .9 .3 mathrm{MeV} ) D. 9. | 12 |

1022 | ( mathbf{8}^{214} boldsymbol{B} boldsymbol{i} quad boldsymbol{alpha}-e m i s s i o n quad boldsymbol{A} quad boldsymbol{beta}-e m i s s i o boldsymbol{n} ) ( boldsymbol{B} stackrel{boldsymbol{beta}-text {emission}}{longrightarrow} boldsymbol{C} quad boldsymbol{beta}- )emission ( boldsymbol{D} stackrel{boldsymbol{alpha}-boldsymbol{e} boldsymbol{m} i boldsymbol{s} boldsymbol{s} i boldsymbol{o} boldsymbol{n}}{boldsymbol{}} boldsymbol{E} ) ( E^{prime} ) is an element of stable nucleus. What is the element’ ( ‘ E ) ‘? ( mathbf{A} cdot_{81}^{207} T l ) B. 206 82 ( mathrm{Pb} ) C ( cdot 206 ) 80 ( mathrm{Hg} ) D. 206 79 | 12 |

1023 | There are ( _{–}-_{–} ) isotopes of Carbon A. 0 B. ( c cdot 2 ) D. | 12 |

1024 | Mark the correct statements: This question has multiple correct options A. The nuclear force between two protons is always greater than the electromagnetic force between them B. The electromagnetic force between two protons is always greater than the gravitational force between them C. The gravitational force between two protons may be greater than the nuclear force between them D. Electromagnetic force between two protons may be greater than the nuclear acting between them. | 12 |

1025 | Health hazards related to nuclear radiations are: A. They can cause cancer B. They can cause deformity in the body c. They can damage the genes of a person. D. All of the above. | 12 |

1026 | The half-life of a radioactive element is 8 hours. A given number of nuclei of that element is reduced to ( 1 / 4 ) of that number after two hours. A . True B. False | 12 |

1027 | The atomic number ( (A) ) and mass number ( (M) ) of the nuclide formed where three alpha ( alpha ) and two ( beta ) particles are emitted from ( 238_{92}^{238} U ) A. ( A=87, M=233 ) В. ( A=86, M=226 ) c. ( A=88, M=227 ) D. ( A=88, M=226 ) | 12 |

1028 | Radioactivity is generally does not found in: This question has multiple correct options A. light nuclei B. stable nuclei C . heavy nuclie D. nuclei of intermediate mass | 12 |

1029 | Assuming that about 20 MeV of energy is released per fusion reaction ( _{1} H^{2}+1 ) ( boldsymbol{H}^{2} rightarrow_{2} boldsymbol{H} boldsymbol{e}^{4}+boldsymbol{E}+ ) other particles, then the mass of ( _{1} H^{2} ) consumed per day in a fusion reactor of power 1 megawatt will approximately be A . ( 0.001 mathrm{g} ) B. 18 c. ( 10.0 mathrm{g} ) D. 1000 | 12 |

1030 | The binding energies per nucleon for deuteron ( left(_{1} H^{2}right) ) and helium ( left(_{2} H e^{4}right) ) are ( 1.1 mathrm{MeV} ) and ( 7.0 mathrm{MeV} ), respectively. Calculate the energy released when two deuterons fuse to form a helium nucleus ( left(_{2} boldsymbol{H} e^{4}right) ) | 12 |

1031 | The nuclear radius of a nucleus with nucleon number 16 is ( 3 times 10^{-15} m ) Then, the nuclear radius of a nucleus with nucleon number 128 is : A ( cdot 3 times 10^{-15} mathrm{m} ) B . ( 1.5 times 10^{-15} m ) ( mathbf{c} cdot 6 times 10^{-15} m ) D. ( 4.5 times 10^{-15} mathrm{m} ) | 12 |

1032 | The end product of the decay of ( _{90} T h^{232} ) is ( _{32} P b^{208} ). The number of cc and fa- particles emitted are respectively ( A cdot 6,4 ) B. 3,3 ( c cdot 4,6 ) D. 6,0 | 12 |

1033 | ( _{19}^{39} K ) and ( _{20}^{40} C a ) are : A. Isotopes B. Isobars C. Isotones D. Isodiaphers | 12 |

1034 | When the number of nucleons in nuclei increases, the binding energy per nucleon A. increases continuously with mass number B. decreases continuously with mass number c. remains constant with mass number D. first increases and then decreases with increase of mass number | 12 |

1035 | Find whether ( alpha- ) decay or any of the ( beta- ) decay are allowed for ( _{89}^{226} A c ) | 12 |

1036 | The count rate of a radioactive source at ( t=0 ) was 1600 counts/s and at ( t=8 s, ) it was 100 counts/s. The count rate (in counts) at ( t=6 s ) will be A . 150 B. 200 ( c .300 ) D. 400 | 12 |

1037 | What is the number of electrons that would weigh ( 1 k g ) ? Mass of an electron is ( 9.11 times 10^{-31} k g ) | 12 |

1038 | Write one balanced reaction representing nuclear fusion. | 12 |

1039 | A radioactive nucleus undergoes a series of decays according to the scheme ( boldsymbol{A} stackrel{boldsymbol{alpha}}{longrightarrow} boldsymbol{A}_{1} stackrel{boldsymbol{beta}}{longrightarrow} boldsymbol{A}_{2} stackrel{boldsymbol{alpha}}{longrightarrow} boldsymbol{A}_{3} stackrel{gamma}{longrightarrow} boldsymbol{A}_{4} ) If the mass number and atomic number of ( A ) are 180 and ( 72, ) respectively, then what are these number for ( boldsymbol{A}_{4} ) ? A. 172 and 69 B. 174 and 70 c. 176 and 69 D. 176 and 70 | 12 |

1040 | A good moderator should A. be a gas B. have an appetite for neutrons c. be lighter in mass number D. be heavier in mass number | 12 |

1041 | A radioactive sample decays by two different processes. Half-life of first process is ( t_{1}, ) and for second process is ( t_{2} . ) Then, the effective half-life is A ( cdot t_{1}-t_{2} ) в. ( t_{1}+t_{2} ) c. ( frac{t_{1}, t_{2}}{t_{1}+t_{2}} ) D. ( frac{t_{1}^{2}+frac{2}{2}}{t_{1}-t_{2}} ) | 12 |

1042 | Write the S.I. unit of activity. A. Becquerel в. Henry ( mathrm{c} cdot O h m ) D. Mendel | 12 |

1043 | Which particle is used to bombard ( 13 A I^{28} ) togive ( _{15} P^{31} ) and a neutron? A. ( alpha ) -particle B. Deuteron c. Proton D. Neutron | 12 |

1044 | ( mathbf{7}^{mathbf{N}^{mathbf{1 4}}}+_{mathbf{2}} mathbf{H} e^{mathbf{4}} rightarrow mathbf{X}+_{mathbf{1}} boldsymbol{H}^{mathbf{1}} ; mathbf{X} ) is ( mathbf{A} cdot_{9} F^{18} ) В. ( _{10} N e^{18} ) ( mathbf{c} cdot_{8} O^{17} ) ( mathrm{D} cdot_{6} C^{15} ) | 12 |

1045 | Atomic mass number of an element is 232 and its atomic number of ( 90 . ) The end product of this radioactive element is an isotopes of lead (atomic mass 208 and atomic number 82 ). The number of ( alpha ) and ( beta- ) particles emitted are : A. ( alpha=3, beta=3 ) в. ( alpha=6, beta=4 ) c. ( alpha=6, beta=0 ) D. ( alpha=4, beta=6 ) | 12 |

1046 | ( ^{200} boldsymbol{X} rightarrow^{110} boldsymbol{A}+^{90} boldsymbol{B}+boldsymbol{E} boldsymbol{n} e boldsymbol{r} boldsymbol{g} boldsymbol{y} ) If the binding energy per nucleon for ( X, A ) and ( B ) are ( 7.4 mathrm{MeV}, 8.2 mathrm{MeV} ) and 8.2 MeV respectively, the minimum energy required to bring in this reaction will be : A. 90 Mev B. 100 MeV c. 120 Mev D. 160 Mev | 12 |

1047 | Neutron decay in free space is given as follows ( mathbf{o} boldsymbol{n}^{mathbf{1}} longrightarrow mathbf{1} boldsymbol{H}^{mathbf{1}}+mathbf{i} boldsymbol{e}^{mathbf{0}}+[mathbf{]} ) Then the parenthesis [] represents a A. neutrino B. photon c. antineutrino D. graviton | 12 |

1048 | The nucleus ( _{n}^{m} X ) emits ( alpha ) particle and 2 ( boldsymbol{beta} ) particles. The resulting nucleus is: A ( m-4 ) ( n-2 ) В ( cdot m-6 ) ( n-4 ) ( mathbf{c} cdot_{n}^{m-6} Z ) D. ( _{n}^{m-4} X ) | 12 |

1049 | Half-life of a radioactive material is 693 yr. Calculate the value of decay constant of material | 12 |

1050 | In carbon cycle of fusion, 4 protons combine to yield one alpha particle and A. one positron B. two positrons c. ten positrons D. three positrons | 12 |

1051 | Statement A: Density of nucleus is independent of its mass number Statement B: Beryllium is used as a moderator in nuclear reactors A. Both A and B are correct B. Both A and B are wrong C. A is correct,B is wrong D. A is wrong,B is correct | 12 |

1052 | Hydrogen atom will be in its ground state, if its electron is in A. any energy level B. the lowest energy state c. the highest energy state D. the intermediate state | 12 |

1053 | 1 a.m. ( u ) is equivalent to ( mathbf{A} cdot 931 mathrm{MeV} ) В. ( 139 mathrm{MeV} ) ( mathbf{c} .93 mathrm{MeV} ) D. ( 39 mathrm{MeV} ) | 12 |

1054 | The first atomic reactor was made by A. Fermi B. Bohr c. Taylor D. Rutherford | 12 |

1055 | Select correct alternative: Statement -1: Photoelectric effects supports quantum nature of light because electronic charge of the photoelectron is quantized. Statement – 2 : The number of ( boldsymbol{alpha} ) and ( boldsymbol{beta} ) 238 particles emitted when ( mathbf{9 2} ) ( mathbf{2 0 6} ) into ( quad P b ) is 6 and 8 ( mathbf{8 2} ) Statement – 3: If the angular momentum of a system is constant in magnitude then the torque (if any) acting on the system must be perpendicular to the angular momentum. A. FFF B. TFT c. TFF D. FFT | 12 |

1056 | An atom of an element contains 13 electrons. Its nucleus has 14 neutrons. Find out its atomic number and approximate atomic mass. An isotope has atomic mass 2 units higher. What will be the number of protons, neutrons and electrons in the isotope? | 12 |

1057 | Order of magnitude of density of Uranium nucleus is, ( left[boldsymbol{m}_{boldsymbol{p}}=mathbf{1 . 6 7} timesright. ) ( left.mathbf{1 0}^{-mathbf{2 7}} mathbf{k g}right] ) ( mathbf{A} cdot 10^{20} k g / m^{3} ) B . ( 10^{17} mathrm{kg} / mathrm{m}^{3} ) C. ( 10^{14} mathrm{kg} / mathrm{m}^{3} ) D. ( 10^{11} mathrm{kg} / mathrm{m}^{3} ) | 12 |

1058 | What does mean by mass defect? Establish relation between mass defect and nuclear binding energy. And hence write the expression for binding energy per nucleon. | 12 |

1059 | Fill in the blanks. The nuclear reaction that can not be controlled at present is | 12 |

1060 | Isodiaphers are the atoms of two elements having same values of: A ( cdot p / n ) B . ( (p-n) ) c. ( (n-p) ) D . ( n times p ) | 12 |

1061 | In a nuclear reaction some mass converts into energy. In this reaction total B.E of reactants when compared with that of products is: A. always greater B. always less c. either greater or less D. always equal | 12 |

1062 | 1 unified atomic mass unit (1 ( u ) ) is equal to the A ( cdot 1.66 times 10^{-25} mathrm{kg} ) B . ( 1.66 times 10^{-27} mathrm{kg} ) C ( .1 .66 times 10^{-29} mathrm{kg} ) D. ( 1.66 times 10^{-31} mathrm{kg} ) | 12 |

1063 | In beta decay, the typical Q value is approximately: A ( .2 mathrm{MeV} ) B. 1 MeV ( mathrm{c} cdot 1 mathrm{eV} ) D. ( 10 mathrm{MeV} ) | 12 |

1064 | The particle ( X ) in the following nuclear reaction is ( frac{13}{7} mathrm{N} longrightarrow_{6}^{13} mathrm{C}+_{1}^{0} mathrm{e}+X ) A. ( P ) B. ( mathbf{c} cdot e^{-} ) ( D ) | 12 |

1065 | The equation ( 4_{1}^{1} H^{2} rightarrow_{2}^{4} H e^{2+}+2 e^{+1}+ ) ( 26 M e V ) represents A. ( beta- ) decay B. ( gamma- ) decay c. fusion D. fission | 12 |

1066 | The modern atomic mass unit is based on the mass of : A. C-12 isotope B. hydrogen c. oxygen D. nitrogen | 12 |

1067 | The Binding energy per nucleon of ( _{3}^{7} L i ) and ( _{2}^{4} H e ) nucleon are ( 5.60 M e V ) and 7.06 ( M e V ), respectively. In the nuclear reaction ( _{3}^{7} L i+_{1}^{1} H rightarrow_{2}^{4} H e+_{2}^{4} H e+Q ) the value of energy ( Q ) released is A. ( 19.6 mathrm{MeV} ) в. ( -2.4 mathrm{MeV} ) c. ( 8.4 mathrm{MeV} ) D. ( 17.3 mathrm{MeV} ) | 12 |

1068 | The kinetic energy (in keV) of the alpha particle, when the nucleus ( _{84}^{210} ) Po at rest undergoes alpha decay, is ( A .5319 ) в. 5422 c. 5707 D. 5818 | 12 |

1069 | Isotopes of an element do not have: A. same number of electrons B. same physical properties c. same chemical properties D. same electrical charge on the nucleus | 12 |

1070 | Explain binding energy curve.Write its importance.What is gamma decay? Explain with example. | 12 |

1071 | A proton and a neutron are both shot at ( 100 m s^{-1} ) toward a ( _{6}^{12} C ) nucleus. Which particle, if either, is more likely to be absorbed by the nucleus? A. The proton. B. The neutron c. Both particles are about equally likely to be absorbed D. Neither particle will be absorbed | 12 |

1072 | Assertion: The atomic bomb uses the principle of nulcear fission. Reason: Nuclear fusion reaction requires high temperatures. A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion c. Assertion is true but Reason is false D. Assertion is false but Reason is true E. Both Assertion and Reason are false | 12 |

1073 | Complete the following statement. All İsotopes of Uranium have A. the same atomic number and the same mass number. B. different atomic numbers but the same mass number. c. different atomic numbers and different mass numbers. D. the same atomic number but different mass numbers. E. no electrons. | 12 |

1074 | The activity of radioactive sample is measured as 9750 counts per minute at ( t=0 ) and as 975 counts per minute at ( t=5 ) minutes, the decay constant is approximately A . 0.922 per minute B. 0.270 per minute c. 0.461 per minute D. 0.39 per minute | 12 |

1075 | If ( I ) excitation energy for the ( H- ) like (hypothetical) sample is ( 24 e V ), then binding energy in ( I I I ) excired state is: A .2 eV в. 3 eV ( c .4 e V ) D. 5 eV | 12 |

1076 | A nucleus, with mass number ( m ) and atomic number ( n, ) emits one ( alpha ) particle and one ( beta ) particle. The mass number and atomic number of the resulting nucleus will be respectively (Assume ( beta ) is positron) A. ( (m-2), n ) B. ( (m-4),(n-1) ) c. ( (m-4),(n-2) ) D. ( (m+4),(n-1) ) | 12 |

1077 | The mass and energy equivalent to 1 amu are respectively A ( cdot 1.67 times 10^{-27} g m, 9.30 mathrm{MeV} ) В. ( 1.67 times 10^{-27} ) к ( g ), 930 Ме ( V ) C . ( 1.67 times 10^{-27} mathrm{kg}, 1 mathrm{MeV} ) D. ( 1.67 times 10^{-34} k g, 1 M e V ) | 12 |

1078 | A radioactive substance ( X ) decays into another radioactive substance ( Y ) Initially only ( X ) was present, ( lambda x ) and ( lambda y ) Number of nuclei ( N_{y} ) will be maximum | 12 |

1079 | If a heavy nucleus has N/Z ratio higher than that required for stability, then: A . it emits ( beta^{-} ) B. It emits ( beta^{+} ) c. It emits ( alpha ) particle D. None of these | 12 |

1080 | The change in the nucleus to form a new nuclide from a parent nucleus is called : A. binding energy B. transmutation c. stability D. generation E. synthesis | 12 |

1081 | The mean lives of a radioactive material for ( alpha ) and ( beta ) radiations are 1620 years and 520 years respectively. The material decays simultaneously for ( alpha ) and ( beta ) radiations.The time after which one fourth of the material remains undecayed is A. 546 years B. 324 years c. 720 years D. 840 years | 12 |

1082 | The energy equivalent of ( 1 mathrm{mg} ) of mass in joule is ( A cdot 3 times 10^{2} ) B. 3 times10 ( ^{10} ) ( c cdot 9 times 10^{10} ) D. ( 9 times 10^{2} ) | 12 |

1083 | A radioactive nucleus undergoes ( alpha ) emission to form a stable element.What will be the recoil of the daughter nucleus if ( v ) is the velocity of ( alpha ) emission? A ( cdot frac{4 v}{A-4} ) в. ( frac{2 v}{A-4} ) c. ( frac{4 v}{A+4} ) D. ( frac{2 v}{A+4} ) | 12 |

1084 | Radioactivity can be effected by : A. temperature B. pressure c. radiation D. all of these | 12 |

1085 | Which of the following statements about radioactivity is/are true? This question has multiple correct options A. It involves outer electrons activity B. It is not affected by temperature or pressure C. It is an exothermic process D. The radioactivity of an element is not affected by any other element compounded by it | 12 |

1086 | Assertion In alpha decay of different radioactive nuclides, the energy of alpha particles has been compared. It is found that as the energy of alpha particle increases the half-life of the decay goes on decreasing. Reason More is the energy in any decay process, more is the probability of decaying the nuclide which leads to faster rate of decay. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct | 12 |

1087 | What is the maximum value of binding energy per nucleon? ( A cdot 8 mathrm{MeV} ) B. 8.8 MeV c. 7.6 Mev D. 1.1 Mev | 12 |

1088 | The energy released by the Hiroshima bomb was originally thought to be equivalent to the destructive power of approximately A. 2000 tons of TNT B. 20000 tons of TNT c. 200000 tons of TNT D. 2000000 tons of TNT | 12 |

1089 | A radioactive isotope has a ( t_{1 / 2} ) of 10 days. If today there is ( 125 g ) of it left then its weight 40 days earlier is A . 6009 в. ( 1000 g ) c. ( 1250 g ) D. 2000g | 12 |

1090 | A radioactive element X disintegrates successively as under: ( boldsymbol{X} stackrel{boldsymbol{alpha}}{rightarrow} boldsymbol{X}_{1} stackrel{boldsymbol{beta}}{rightarrow} boldsymbol{X}_{2} stackrel{boldsymbol{alpha}}{rightarrow} boldsymbol{X}_{3} stackrel{gamma}{rightarrow} boldsymbol{X}_{4} ) If the atomic number and atomic mass. Number of ( X ) are 72 and ( 180 . ) What are the corresponding values for ( boldsymbol{X}_{mathbf{4}} ) A .69,176 B. 69,172 c. 71,176 D. 71,172 | 12 |

1091 | 63. An element X decays, first by positron emission and then two -particles are emitted in successive radioactive decay. If the product nucleus has a mass number 229 and atomic number 89, the mass number and atomic number of element X are (a) 237,93 (b) 237,94 (c) 221, 84 (d) 237,92 | 12 |

1092 | ( boldsymbol{alpha}, boldsymbol{beta} ) and ( gamma ) -rays emitted from a radioactive source are passed through a ( 0.5 c m ) thick aluminium sheet. The out going radiations will consist of A. ( alpha, beta ) and ( gamma ) -rays B. ( gamma ) and ( beta ) -rays only c. ( gamma ) rays only D. ( alpha ) rays only | 12 |

1093 | When ( _{90} T^{228} ) transforms to ( _{83} B i^{212}, ) then the number to the emitted ( alpha ) and ( beta ) particles is, respectively: ( mathbf{A} cdot 8 alpha, 7 beta ) в. ( 4 alpha, 7 beta ) c. ( 4 alpha, 4 beta ) D. ( 4 alpha, 1 beta ) | 12 |

1094 | The reaction responsible for the production of light energy from the sun will be: A . fission B. fusion c. nuclear D. none of these | 12 |

1095 | ( frac{1}{16} ) part of a radioactive material is left after one hour. It’s half life is ? A. 45 min B. 30 min c. 20 min D. 15 min | 12 |

1096 | Match list I and list II. List I List II | 12 |

1097 | Mass of one twelth of carbon atom is called atomic mass unit. A. True B. False | 12 |

1098 | The strongest attractive forces are A. electrostatic B. gravitational c. nuclear D. nothing can be decided | 12 |

1099 | Among the following which is used to control the rate of reaction in nuclear fission reactions? A. water B. Heavy water c. Cadmium D. Graphite | 12 |

1100 | A radioactive sample has initial concentration ( N_{0} ) of nuclei. Then This question has multiple correct options A. the number of undecayed nuclei present in the sample decays exponentially with time B. the activity (R) of the sample at any instant is directly proportional to the number of undecayed nuclei present in the sample at that time c. the number of decayed nuclei growth exponentially with time D. the number of decayed nuclei grows linearly with time | 12 |

1101 | The instability of the nucleus can be due to various cause.An unstable nucleus emits radiations if possible to transform into less unstable state.Then the cause and the result can be This question has multiple correct options A. a nucleus of excess nucleons is ( alpha ) active B. an excited nucleus of excess protons is ( beta^{-} ) active C. an excited nucleus of excess protons is ( beta^{+} ) active D. an nucleus of excess neutrons is ( beta^{-} ) active | 12 |

1102 | The number ( N_{X} ) of nuclei of ( X ) at time ( boldsymbol{t}=boldsymbol{T}_{1 / 2} ) is A ( cdot frac{K+lambda N_{0}}{2 lambda} ) в. ( left(2 lambda N_{0} Kright) frac{1}{lambda} ) ( ^{mathbf{c}} cdotleft[lambda N_{0}+frac{K}{2}right] frac{1}{lambda} ) D. Data insufficient | 12 |

1103 | ( D_{2} O ) or graphite is a moderator in nuclear reactor A. True B. False | 12 |

1104 | Nuclei of a radio-active element ( A ) are being product at a constant rate ( alpha ). The element has a decay constant ( lambda ). At time ( t=0 ) there are ( N_{0} ) nuclei of the element present (a) Calculate the number of nuclei ( A ) as a function of time ( t ) (b) If ( alpha=2 N_{0} lambda ), calculate the number of nuclei of ( A ) after one half-life of ( A ) and also the limiting value of ( N ) as ( t rightarrow ) ( infty ) | 12 |

1105 | Nuclear fusion reactions cannot be harnessed for productive applications because: A. These reactions require very high temperature and are controllable. B. These reactions require very high temperature and are uncontrollable c. These reactions require very low temperature and are uncontrollable D. These reactions require very low temperature and are controllable | 12 |

1106 | Rest mass energy of an electron is 0.54 MeV. If velocity of the electron is ( 0.8 mathrm{C} ) then its kinetic energy will be: A. ( 0.36 mathrm{MeV} ) B. 0.41 Mev c. 0.48 Mev D. 1.32 MeV | 12 |

1107 | On the bombardment of Boron with neutron, an ( alpha ) – particle is emitted and product nucleus formed is ( mathbf{A} cdot_{6} C^{12} ) В ( cdot_{2} L^{i} ) ( mathrm{c} cdot_{3} L i^{7} ) D・ ( _{4} B e^{9} ) | 12 |

1108 | Which of the following is/are example(s) of isotopes? A. Oxygen and Ozone B. Ice and Steam c. Nitric oxide and Nitrogen dioxide D. Hydrogen and Deuterium | 12 |

1109 | Two radioactive materials ( X_{1} ) and ( X_{2} ) have decay constants ( 10 lambda ) and ( lambda ) respectively. If finally they have the same number of nuclei, then the ratio of the number of nuclei of ( X_{1} ) to that of ( X_{2} ) will be ( 1 / ) e after a time A. ( frac{1}{10 lambda} ) в. ( frac{1}{11 lambda} ) c. ( frac{11}{10 lambda} ) D. ( frac{1}{9 lambda} ) | 12 |

1110 | UM 2016) 36. A radioactive nucleus A with a half-life T, decays into nucleus B. At t = 0, there is no nucleus B. At some time t, the ratio of the number of B to that of A is 0.3. Then, is given by (a) t = T log (1.3) (b) t = 7 log(1.3) Dan (d) t =T log1.3 2 log1.3 log2 (JEE Main 2017) T (c) t = I log2 | 12 |

1111 | Mass of proton ( =1.00760 a m u, ) mass of neutron ( =1.00899 a m u, ) mass of deuterium nucleus ( =2.0147 a m u . ) Then binding energy is : в. ( 1.76 a m u ) c. ( 1.76 M e V ) D. ( 10^{15} ) joules | 12 |

1112 | Plutonium has atomic mass 210 and a decay constant equal to ( 5.8 times 10^{-8} s^{-1} ) The number of ( alpha- ) particles emitted per second by 1 mg plutonium is (Avogadro’s constant ( left.=mathbf{6 . 0} times mathbf{1 0}^{mathbf{2 3}}right) ) A ( cdot 1.7 times 10^{9} ) B . ( 1.7 times 10^{11} ) c. ( 2.9 times 10^{11} ) D. ( 3.4 times 10^{9} ) | 12 |

1113 | ( ln operatorname{an} alpha ) -decay the kinetic energy of ( alpha ) particle is ( 48 mathrm{MeV} ) and ( Q ) -value of the reaction is ( 50 ~ M e V ). The mass number of the molecular nucleus is ( X ). Find value of ( boldsymbol{X} / mathbf{2 5} ) (Assume that daughter nucleus is in ground state.) A .2 B. 4 ( c cdot 6 ) D. 8 | 12 |

1114 | 75. The compound unstable nucleus 23. U often decays in accordance with the following reaction 23 U 34Xe + 3 Sr+ other particles In the nuclear reaction presented above, the “other particle” might be (a) an alpha particle, which consists of two protons and two neutrons (b) two protons (c) one proton and one neutron (d) two neutrons | 12 |

1115 | 67. If a nucleus such as 226Ra that is initially at rest undergoes a-decay, then which of the following statements is true? (a) The alpha particle has more kinetic energy than the daughter nucleus. (b) The alpha particle has less kinetic energy than the daughter nucleus. (c) The alpha particle and daughter nucleus both have same kinetic energy (d) We cannot say anything about kinetic energy of alpha particle and daughter nucleus. | 12 |

1116 | The binding energies of nuclei ( X ) and ( Y ) are ( boldsymbol{E}_{1} ) and ( boldsymbol{E}_{2}, ) respectively. Two atoms of ( X ) fuse to give one atom of ( Y ) and an energy ( Q ) is released. Then, A ( cdot Q=2 E_{1}-E_{2} ) в. ( Q=E_{2}-2 E_{1} ) c. ( QE_{2}-2 E_{1} ) | 12 |

1117 | A radio isotope ( X ) has a half life of ( 10 s ) Find the number of active nuclei in the sample (if initally there are 1000 isotopes which are falling from rest from a height of ( 3000 m ) ) when it is at a height of ( 1000 m ) from the reference plane: ( mathbf{A} .50 ) в. 250 c. 29 D. 100 | 12 |

1118 | For the fast chain reaction, the size of ( U^{235} ) block, as compared to its critical size, must be A. greater B. smaller c. same D. anything | 12 |

1119 | The ratio of the amounts of energy released as a result of the fusion of ( 1 k g ) hydrogen ( left(E_{1}right) ) and fission of ( 1 k g ) of ( mathbf{9 2} boldsymbol{U}^{mathbf{2 3 6}}left(boldsymbol{E}_{mathbf{2}}right) ) will be: A . 1.28 B. 3.28 c. 5.28 D. 7.28 | 12 |

1120 | ( 50 % ) of a radio active substance decays in 5 hours. The time required for the ( 87.5 % ) decay is A. 10 hours B. 15hours c. 12.5 hours D. 17.5 hours | 12 |

1121 | An atomic nucleus ( A ) is composed of 84 protons and 128 neutrons. (i) The nucleus ( A ) emits an alpha particle and is transformed into nucleus ( B ). What is the composition of nucleus ( B ? ) (iii) The nucleus ( B ) emits a beta particle and is transformed into a nucleus ( C . ) What is the composition of nucleus ( C ? ) ( (i i i) ) Does the composition of nucleus ( C ) change if it emits gamma radiations? | 12 |

1122 | When a ( U^{238} ) nucleus originally at rest, decay by emitting an alpha particle having a speed ( 1.5 times 10^{7} m^{-1} . ) Then calculate the kinetic energy of the residual nucleus. | 12 |

1123 | Direction for Question 27: The question contains Statement 1 and Statement 2. Of the four choices given, choose the one that best describes the two statements. 27. Statement 1: Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion. Statement 2: For heavy nuclei, binding energy per nucleon increases with increasing Z while for light nuclei it decreases with increasing Z. (a) Statement 1 is true but statement 2 is false. (b) Statement l is false but statement 2 is true, (c) Statement l is true, statement 2 is true; statement 2 is the correct explanation for statement 1. (d) Statement 1 is true, statement 2 is true; statement 2 is not the correct explanation for statement 1. (AIEEE 2008) | 12 |

1124 | State whether the given statement is true or false: Atomic mass of an element is same as | 12 |

1125 | The energy released per fission of Uranium is ( 200 mathrm{MeV} ). Determine the number of fission per second required to generate 2MW power. ( mathbf{A} cdot 6.25 times 10^{16} ) B. ( 0.25 times 10^{16} ) C. ( 1.25 times 10^{16} ) D ( .25 times 10^{16} ) | 12 |

1126 | Which of the following reasons make nuclear waste an extremely potent pollutant? This question has multiple correct options A. It causes mutations at a very high rate B. It is responsible for heating of Earths surface and atmosphere C. It is a very challenging task to provide safe disposal of radioactive wastes D. All of the above | 12 |

1127 | When a neutron collides with a quasi free proton, it loses half of its energy on the average in the every collission. How many collisions, on the average, are required to reduce a 2 MeV neutron to a thermal energy df ( 0.04 mathrm{eV} ) A . 30 B. 22 ( c .35 ) D. 26 | 12 |

1128 | 1. If N, is the original mass of a substance of half-life period 1/2 = 5 years, then the amount of substance left after 15 years is No (b) 16 2100 zla 21+ (AIEEE 2002) lacion of od: | 12 |

1129 | 70. What is the age of an ancient wooden piece if it is known that the specific activity of Cl4 nuclide in it amounts to 3/5 of that in fresh trees? Given: the half of C nuclide is 5570 years and loge (5/3) = 0.5. (a) 1000 years . (b) 2000 years (c) 3000 years (d) 4000 years | 12 |

1130 | If a star can convert all the ( H e ) nuclei completely into oxygen nuclei, the energy released per oxygen nuclei is [Mass of ( H e ) nucleus is ( 4.0026 a m u ) and mass of oxygen nucleus is ( 15.9994 a m u ) A. ( 7.6 mathrm{MeV} ) B. 56.12 MeV c. ( 10.24 mathrm{MeV} ) D. ( 23.9 mathrm{MeV} ) | 12 |

1131 | The radioactivity of certain radioactive element drops to ( left(frac{1}{8}right)^{text {th }} ) of its initial value in 30 second, its half life is: A. 15 second B. 5 second c. 4 second D. 10 second | 12 |

1132 | A system of binary stars of masses ( boldsymbol{m}_{boldsymbol{A}} ) and ( m_{B} ) are moving in circular orbits of radii ( r_{A} ) and ( r_{B}, ) respectively. If ( T_{A} ) and ( T_{B} ) are the time periods of masses ( m_{A} ) and ( m_{B}, ) respectively then ( stackrel{T_{A}}{T_{B}}=left(frac{r_{A}}{r_{B}}right)^{frac{3}{2}} ) B ( left.cdot T_{A}>T_{B} text { (if } r_{A}>r_{B}right) ) c. ( T_{A}>T_{B} ) (if ( m_{A}>m_{B} ) ) D. ( T_{A}=T_{B} ) | 12 |

1133 | The energy released when a positron is annihilated is : A. ( 0.52 mathrm{MeV} ) B. 5.3Mev c. 185 Mev D. 200MeV | 12 |

1134 | 37. N, atoms of a radioactive element emit N, beta particles per second. The decay constant of the element is (in s) Ni N (a) (b) N N, (c) , In (2) (d) N, In (2) | 12 |

1135 | 20. When zLi’ nuclei are bombarded by protons, and the resultant nuclei are Be®, the emitted particles will be (a) gamma photons (b) neutrons (c) alpha particles (d) beta particles(AIEEE 2006) | 12 |

1136 | Energy in the sun is mainly generated by A. Fusion of radioactive materials B. Fission of helium nucle c. Fusion of hydrogen nuclei D. Chemical reaction | 12 |

1137 | 32. The half-life of a radioactive substance is 20 minutes. The approximate time interval (t2- t) between the time tz when 2/3 of it has decayed and time t, when 1/3 of it had decayed is (a) 7 min (b) 14 min (c) 20 min (d) 28 min (AIEEE 2011) | 12 |

1138 | The fraction of atoms of radioactive element that decays in 6 days is ( 7 / 8 ) The fraction that decays in 10 days will be A. ( frac{77}{88} ) в. ( frac{71}{80} ) c. ( frac{31}{32} ) D. ( frac{15}{16} ) | 12 |

1139 | Binding energy of a nucleus is of the order of. A. Electron volt (ev) B. Kilo electron volt (KeV) c. Mega electron volt (MeV) D. A joule (J) | 12 |

1140 | Write two distinguishing feature of nuclear forces. | 12 |

1141 | What is the atomic mass (u) of chlorine? A . 34 B. 35.5 ( c cdot 33 ) D. 35 | 12 |

1142 | Which of the following are used as nuclear fuel? ( mathbf{A} cdot_{82} P b^{208} ) В ( cdot 92 U^{235} ) ( mathbf{c} cdot_{92} U^{238} ) D. Both (B) and (C) | 12 |

1143 | The conclusion that may be drawn from the experiment which demonstrated radioactivity (A.R) is A. ( A l ) is artificial radioactive substance B. positrons are essential for the production of A.R c. Exponential decay led to the discovery of A.R. D. In A.R., only positrons are produced | 12 |

1144 | Write the decay equations and expressions for the disintegration energy ( Q ) of the following decay: ( beta^{-} ) decay, ( beta^{+} ) decay, electron capture | 12 |

1145 | Explain with an exampple, whether the neutron to proton ratio in a nucleus increases or decreases due to ( beta ) -decay. | 12 |

1146 | Calculate ( Q ) value of the following nuclear reaction. [ _{13} A l^{27}+_{2} H e^{4} longrightarrow_{14} S i^{30}+_{1} H^{1}+Q ] The exact mass of ( _{13} A l^{27} ) is ( mathbf{2 6 . 9 8 1 5} mathbf{a m u},_{mathbf{1 4}} mathbf{S i}^{mathbf{3 0}} mathbf{i s} mathbf{2 9 . 9 7 3 8} boldsymbol{a m u} ) ( _{2} H e^{4} ) is ( 4.0026 a m u ) and ( _{1} H^{1} ) is 1.0078 amu. | 12 |

Hope you will like above questions on nuclei and follow us on social network to get more knowledge with us. If you have any question or answer on above nuclei questions, comments us in comment box.

**help, strategies and expertise**.