Nuclei Questions

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
A ( cdot frac{238}{92} U )
В ( cdot frac{233}{92} U )
( mathbf{c} cdot_{94}^{239} mathrm{Pu} )
D ( cdot frac{203}{90} mathrm{Th} )

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.
A. True
B. False

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
correct?
A ( cdot ) (i) and (ii)
B. (i), (ii) and (iii)
c. (ii) and (iii)
D. (i) and (iii)

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
are unstable
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
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} )
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
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.
A. True
B. False

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
sodium-21 nucleus during the decay?
A. A positron and an antineutrino
B. A positron and a neutrino
c. An electron and an antineutrino
D. An electron and a neutrino

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
processes energy is released.
Calculate the energy release in MeV in the deuterium-tritium fusion reaction:
( mathbf{2} boldsymbol{H}+_{mathbf{1}}^{mathbf{3}} boldsymbol{H} longrightarrow_{mathbf{2}}^{mathbf{4}} boldsymbol{H} boldsymbol{e}+boldsymbol{n} )
Using the data:
( boldsymbol{m}left(_{1}^{2} boldsymbol{H}right)=mathbf{2 . 0 1 4 1 0 2} boldsymbol{u} )
( boldsymbol{m}left(_{1}^{3} boldsymbol{H}right)=mathbf{3} . mathbf{0} mathbf{1 6 0} mathbf{4 9} boldsymbol{u} )
( boldsymbol{m}left(begin{array}{l}4 \ 2end{array} boldsymbol{H} eright)=4.002603 boldsymbol{u} )
( boldsymbol{m}_{boldsymbol{n}}=mathbf{1 . 0 0 8 6 6 5 u} )
( mathbf{1} boldsymbol{u}=mathbf{9 3 1 . 5} boldsymbol{M} boldsymbol{e} boldsymbol{V} / boldsymbol{c}^{2} )

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} )
is ( 7.97 M e V ) and ( m_{p}=1.0078 u ) and
( boldsymbol{m}_{boldsymbol{n}}=mathbf{1 . 0 0 8 7 u} )
A . ( 14899.438 mathrm{MeV} )
в. 148.99 Ме ( V )
c. 4489.73 Ме ( V )
D. 448.973 MeV

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} )
and Y. ( N_{y} ) will be maximum when ( left(N_{y} ) is right.
atoms of ( Y ) )
A ( cdot frac{N_{y}}{N_{x}-N_{y}}=frac{lambda_{y}}{lambda_{x}-lambda_{y}} )
В. ( frac{N_{x}}{N_{x}-N_{y}}=frac{lambda_{x}}{lambda_{x}-lambda_{y}} )
c. ( lambda_{y} N_{y}=lambda_{x} N_{x} )
D. ( lambda_{y} N_{x}=lambda_{x} N_{y} )

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 )
are the disintegration constants of ( boldsymbol{X} )
and ( Y . N_{x} ) and ( N_{y} ) are the number of
nuclei of ( X ) and ( Y ) at any time ( t )

Number of nuclei ( N_{y} ) will be maximum
when
A ( cdot frac{N_{y}}{N_{x}-N_{y}}=frac{lambda_{y}}{lambda_{x}-lambda_{y}} )
В. ( frac{N_{x}}{N_{x}-N_{y}}=frac{lambda_{x}}{lambda_{x}-lambda_{y}} )
( c cdot frac{lambda_{y}}{N_{y}}=frac{lambda_{x}}{N_{x}} )
( mathbf{D} cdot lambda_{y} N_{y}=lambda_{x} N_{x} )

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
( mathbf{A} cdot_{mathbf{1}}^{2} boldsymbol{H}+_{mathbf{1}}^{mathbf{3}} boldsymbol{H} rightarrow_{mathbf{2}}^{mathbf{4}} boldsymbol{H} boldsymbol{e}+_{mathbf{0}}^{mathbf{1}} boldsymbol{n}+mathbf{1 7} mathbf{. 6} boldsymbol{M} boldsymbol{e} boldsymbol{V} )
1. Artificial radioactivity
B. ( _{92}^{235} U+_{0}^{1} n rightarrow_{56}^{143} B a+_{36}^{90} K r+3_{0}^{1} n+ )
( 200 M e v quad ) 2. Isodiaphers
( mathrm{C} cdot_{13}^{23} A l+_{2}^{4} H e rightarrow_{14}^{30} S i+_{1}^{1} H )
3. Atom Bomb
( mathrm{D} cdot_{Z}^{m} boldsymbol{A} stackrel{-alpha^{m-4}}{rightarrow}_{Z-2} boldsymbol{B} )
4. Nuclear Fissio
5. Nuclear Fusion
( A cdot A-5 ; B-3,4 ; C-1 ; D-2 )
B. A – 2; B – 3,4; C – 1; D – 5
c. ( A-1,5 ; B-3 ; C-4 ; D-2 )
D. A – 3,4; B – 1; C – 5; D – 4,2

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
the mass of a single atom of that
element.
A. True
B. False

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

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