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

#### List of semiconductor electronics: materials, devices and simple circuits Questions

Question No | Questions | Class |
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1 | Photodiode is a device A. Which is always operated in reverse bias B. Which is always operated in forward bias C. In which photo current is independent of intensity of incident radiation D. Which may be operated in forward or reverse bias |
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2 | A semiconductor ( X ) is made by doping a germanium crystal with arsenic ( (mathrm{Z}= ) 33). A second semiconductor Y is made by doping germanium with indium ( (z= ) 49). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct? A. ( x ) is ( p ) -type, ( Y ) is ( n ) -type and the junction is forward biased B. ( x ) is ( n ) -type, ( Y ) is ( p ) -type and the junction is forward biased c. ( x ) is ( p ) -type, ( Y ) is ( n ) -type and the junction is reverse biased D. ( x ) is ( n ) -type, ( Y ) is ( p ) -type and the junction is reverse biased |
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3 | 7. Barrier potential of a p-n junction diode does not depend on (a) Diode design (c) Forward-biased (b) Temperature (d) Doping density |
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4 | A full-wave rectifier circuit along with the output is shown. The contribution(s) from the diode 1 is (are). A. B. A, C ( c . B, D ) D. ( A, B, C, D ) |
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5 | For an amplitude modulated wave, the maximum amplitude is found to be 10 while the minimum amplitude is found to be ( 2 v ). Determine the modulation index ( mu ) |
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6 | Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of ( V_{o} ) changes by : (assume that the Ge diode has large breakdown voltage) A . ( 0.6 v ) B. 0.8 ( c cdot 0.4 v ) ( D, 0.2 mathrm{v} ) |
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7 | The current gain of a transistor in a Common base arrangement is ( 0.98 . ) The Change in collector current corresponding to a change of ( 5 m A ) in emitter current is : ( mathbf{A} cdot 0.1 m A ) B. ( 0.2 m A ) c. ( 4.9 m A ) D. ( 9.2 m A ) |
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8 | 23. In an NPN transistor, the collector current is 24 mA. If 80% of electrons reach collector, its base current in mA is (a) 36 (b) 26 (c) 16 (d) 6 |
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9 | 20. The forward-biased diode connection is (a) 2 Dwwav (b) 2 Dww*2 v (c) *2 Vww-2v (d) -3Dww-3 v (JEE Main 2014) |
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10 | The binary number of decimal number ( (9.25)_{10} ) is A . 1101.01 в. 1001.01 c. 1001.10 D. 1110.010 |
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11 | A full-wave p-n diode rectifier uses a load resistor of ( 1500 Omega ). No filter is used. The forward bias resistance of the diode is ( 10 Omega . ) the efficiency of the rectifier is A . ( 81.2 % ) B . ( 40.6 % ) c. ( 80.4 % ) D. ( 40.2 % ) |
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12 | The truth-table given below is for which gate? ( begin{array}{lll}A & B & C \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0end{array} ) A. xor B. OR c. AND D. NAND |
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13 | The ratio (R) of output resistance ( r_{0} ) and and the input resistance ( r_{i} ) in measurements of input and output characteristics of a transistor is typically in the range: A . ( R sim 10^{2}-10^{3} ) В. ( R sim 1-10 ) c. ( R sim 0.1-1.0 ) D. ( R sim 0.1-0.01 ) |
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14 | represents 45. Symbol (a) NAND gate (c) NOT gate (b) NOR gate (d) XNOR gate |
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15 | Write the truth table of logic OR gate. | 12 |

16 | The maximum frequency of operation of photodiodes is of the order of: ( mathbf{A} cdot 1 k H z ) в. ( 1 M H z ) c. ( 1 G H z ) D. ( 1 T H z ) |
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17 | With rise in temperature, resistance of a semiconductor material (germanium or silicon) A . increases B. decreases c. remains the same D. first increases then decreases |
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18 | The number of silicon atomes per ( m^{3} ) is ( 5 times 10^{28} . ) This is doped simultaneously with ( 5 times 10^{28} ) atoms per ( m^{3} ) of Arsenic and ( 5 times 10^{20} ) per ( m^{3} ) atoms of Indium. Calculate the number of electrons and holes. Given that ( n_{1}=1.5 times 10^{16} m^{-3} ) Is the material ( n ) -type or ( p- ) type? |
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19 | To get an output ( Y=1 ) in given circuit which of the following input will be correct. ( mathbf{A} cdot A=1 ; B=0 ; C=1 ) В. ( A=1 ; B=1 ; C=0 ) c. ( A=0 ; B=1 ; C=0 ) D. ( A=1 ; B=0 ; C=0 ) |
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20 | State whether given statement is True or False Doping of pure ( S i ) with trivalent impurities, gives p-type semiconductors A. True B. False |
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21 | In p-type semiconductors, holes are: A. majority carriers B. minority carriers ( c . ) absent D. none of the above |
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22 | The minimum number of gates required to realise the expression ( Z= ) ( D A B C+D overline{A B C} ) is A. One B. Two c. Eight D. Five |
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23 | For a transistor, ( beta=100 . ) The value of ( alpha ) is A . 1.01 B. 0.99 ( c cdot 100 ) D. 0.01 |
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24 | If electromagnetic rays are incident on a semiconductors its conductivity. A. Increases B. Increases with increases frequency C. Increases when frequency increases above certain frequency D. Increases when wavelength is increases above a certain wavelength |
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25 | A semiconductor is doped with a donor impurity then [more than one option may be correct This question has multiple correct options A. the hole concentration increases B. the hole concentration decreases the electron concentration increases C. the electron concentration increases D. the electron concentration decreases |
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26 | The potential in the depletion layer is due to: A. electrons B. holes ( c . ) ions D. forbidden band |
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27 | In an LED, the longer lead is always connected to the terminal of the battery and the shorter lead is connected to the terminal of the cell (or battery) A. positive, negative B. negative, positive c. positive, neutral D. neutral, positive |
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28 | Which of the following statement(s) is/are true about holes? A. They flow from positive terminal to negative terminal B. They flow from negative terminal to positive terminal C. They do not flow D. None of these |
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29 | When PNjunction os forward biased the current in junction A. increases B. decreases c. Remains same D. None of these |
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30 | How does a diode acts as a rectifier. | 12 |

31 | Mention practical importance of Zener diode in a laboratory. |
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32 | ( ln a p-n-p ) transistor the base is the n-region. Its width relative to the ( p ) regions is A. smaller B. larger c. same D. not related |
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33 | The conduction band and valency band of a good conductor are A. well separated. B. just touch. c. very close. D. overlapped. |
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34 | Suppose a pure ( boldsymbol{S} boldsymbol{i} ) crystal has ( boldsymbol{5} times ) ( 10^{28} ) atoms ( m^{-3} . ) It is doped by 1 ppm concentration of pentavalent ( boldsymbol{A} boldsymbol{s} ) Calculate the number of electrons and |
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35 | In which bias can a zener diode be used as voltage regulator? |
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36 | In a Zener diode regulated power supply, unregulated DC input of ( 10 V ) is applied. If the resistance ( left(R_{s}right) ) connected in series with a Zener diode is ( 200 Omega ) and the Zener voltage ( V_{z}=5 V ), the current across the resistance ( boldsymbol{R}_{s} ) is: ( mathbf{A} cdot 15 m A ) B. ( 10 mathrm{mA} ) c. ( 20 m A ) D. ( 5 m A ) E . ( 25 m A ) |
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37 | In the circuit shown, assume the diode to be ideal. When ( V_{i} ) increases from ( 2 V ) to ( 6 V ), the change in the current is (in ( boldsymbol{m} boldsymbol{A}) ) A . zero B . 20 ( c cdot 80 / 3 ) D. 40 |
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38 | What is an intrinsic semi conductor? Give two examples. |
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39 | What is a Fermi energy level? What is its position in case of an intrinsic semiconductor? | 12 |

40 | Draw the circuit diagram of AND gate using diodes. | 12 |

41 | In which of the following statements, the obtained impure semiconductor is of p-type? A. Germanium is doped with bismuth B. Silicon is doped with antimony c. Germanium is doped with gallium D. Silicon is doped with phosphorus |
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42 | 55. In order to obtain an output Y = 1 from the circuit of the figure, the inputs must be Во A (a) 0 (b) 1 (c) 1 (d) 1 B 1 0 0 1 C 0 0 1 0 |
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43 | The barrier potential in a p-njunction is ( 0.3 V . ) The current required is ( 6 m A . ) The emf of the cell required for use in the circuit if a resistance of ( 200 Omega ) is connected in series with junction is (in volt) |
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44 | Energy band gap between valence band and conduction band for insulator is: A. Zero B. greater than 9 eV c. less than conductors D. approximately ( 1 e V ) |
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45 | The circuit is equivalent to A. NOR gate B. AND gate c. NAND gate D. or gate |
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46 | The voltage gain of an amplifier with 9 negative feedback is ( 10 . ) The voltage gain without feedback will be A . 90 B. 100 c. 10 D. 1.25 |
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47 | The circuit has two oppositively connected ideal diodes in parallel. What is the current flowing in the circuit? ( mathbf{A} cdot 1.71 A ) B . ( 2.00 A ) c. ( 2.31 A ) D. ( 1.33 A ) |
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48 | Reverse bias applied to a p-njunction diode A. Lowers the potential barrier B. Decreases the majority charge carriers C. Raises the potential barrier D. Change the mass of ( p ) -n junction diode |
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49 | The energy band gap (distance between the conduction band and valence band) in conductor is. ( mathbf{A} cdot mathbf{0} ) в. 4 А ( c cdot 10^{circ} ) ( mathbf{D} cdot_{100 A}_{A}^{circ} ) |
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50 | Draw the circuit diagram of a full wave rectifier using two p-njunction diodes and explain its working. Show the input and output waveforms. |
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51 | Construct the logic symbol, Boolean expression and truth table for an AND gate. |
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52 | If the load resistance decreases in a zener regulator, the zener current A. Decreases B. Stays the same c. Increases D. Equals the source voltage divided by the series resistance |
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53 | Name the device used to make a circuit function, only when needed? |
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54 | Make logic symbol and write Boolean expression of NOT gate. | 12 |

55 | When an input signal 1 is applied to a NOT gate, its output is ( mathbf{A} cdot mathbf{1} ) B. 0 c. either 0 or 1 D. both 0 and 1 |
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56 | In ( n ) -p-n transistor, the arrow head on emitter represents that the conventional current flows from A. base to emitter. B. emitter to base c. emitter to collector. D. base to collector. |
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57 | In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is: A. an n-type semiconductor B. a p-type semiconductor ( c . ) an insulator D. a meta |
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58 | The transistor are usually made of A. metal oxides with high temperature coefficient of resistivity. B. metals with high temperature coefficient of resistivity. C. metals with low temperature coefficient of resistivity. D. semiconducting materials having low temperature coefficient of resistivity. |
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59 | In a p-njunction having depletion layer of thickness ( 10^{-6} m ), the potential across it is ( 0.1 mathrm{V} ). The electric field is A ( cdot 10^{7} V / m ) В ( cdot 10^{-6} V / m ) c. ( 10^{5} V / m ) D. ( 10^{-5} V / m ) |
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60 | In p-type semiconductor, conduction is due to A. greater number of holes and less number of electrons. B. only electrons. C . only holes. D. greater number of electrons and less number of holes. |
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61 | At absolute zero, Si acts as A. non-metal B. metal c. insulator D. semiconductor |
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62 | The output ( (X) ) of the logic circuit shown in the figure will be ( mathbf{A} cdot X=bar{A} . bar{B} ) В . ( X=overline{A . B} ) ( mathbf{c} . X=A . B ) D. ( X=overline{A+B} ) |
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63 | In n-type semiconductor, majority charge carriers are A. electrons B. neutrons c. holes D. protons |
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64 | In metals, the conduction bands are incompletely filled orbitals that allow electrons to flow. A. true B. false c. orbit D. none of these |
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65 | Assertion Intrinsic semiconductors are undoped Reason Holes in the valence band are vacancies |
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66 | 11. If in a pn junction diode, a square input signal of 10 V is applied as shown, -sv then the output signal across R, will be (a) +5 V (b) – 10 V – 10v (d) -5V (AIEEE 2007) |
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67 | With a neat circuit diagram, explain the working of a single stage ( C E ) amplifier. Draw the frequency response curve and discuss the results. | 12 |

68 | A student wants to use two p-njunction diodes to convert alternating current into direct current. Draw the labelled circuit diagram he/she would use and explain how it work |
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69 | The intrinsic conductivity of germanium at ( 27^{circ} mathrm{C} ) is ( 2.13 mathrm{mho} / mathrm{m} ) and mobilities of electrons and holes are 0.38 and ( 0.18 m^{2} / V s ) respectively. The density of charge carriers is ( mathbf{A} cdot 2.37 times 10^{19} / m^{3} ) B. ( 3.28 times 10^{19} / m^{3} ) C. ( 7.83 times 10^{19} / m^{3} ) D. ( 8.47 times 10^{19} / m^{3} ) |
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70 | Resistor is coloured as green – orange – yellow – gold,its resistance will be: A. ( 53 times 10^{4} pm 10 % ) В. ( 54 times 10^{4} pm 10 % ) c. ( 42 times 10^{4} pm 10 % ) D. ( 53 times 10^{4} pm 5 % ) |
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71 | How is a Zener diode fabricated? What causes the setting up of high electric field even for small reverse bias voltage across the diode? Describe, with the help of a circuit diagram, the working of Zener diode as a voltage regulator. |
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72 | 1. Three semiconductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is (a) Tellurium, germanium, silicon (b) Tellurium, silicon, germanium (c) Silicon, germanium, tellurium (d) Silicon, tellurium, germanium |
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73 | The current gain in the common emitter amplifier mode of a transistor is ( 10 . ) The input impedance is ( 20 k Omega ) and load of resistance is ( 100 k Omega ). The power gain is : A. 300 в. 500 ( c cdot 200 ) D. 100 |
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74 | The circuit as shown in figure, the equivalent gate is A. NOR gate B. oR gate c. AND gate D. NAND gate |
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75 | Indium impurity in germanium makes A. n-type B. p-type c. insulator D. intrinsic |
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76 | Match List-1 with list-2 ( begin{array}{ll}text { List-1 } & text { List-2 } \ text { A. Emitter } & text { E. Transistor } \ text { B. Base } & text { F. Moderately doped } \ text { C. Collector } & text { G. Lightly doped } \ text { D. Transfer of resistance } & text { H. Heavily doped } \ text { I. largest physical size }end{array} ) A. A-F B-E C-H,I D-G B. A-G B-F.I C-E D-H c. A-HB-G C-F,I D-E D. A-E B-H,I C-G D-F |
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77 | What are Forward and Reverse bias conditions of a Diode? |
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78 | The circuit has two oppositely connect ideal diodes in parallel. What is the current following in the circuit? A ( .1 .33 A ) в. 1.71 А ( c .2 .00 A ) D. ( 2.31 A ) |
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79 | The output of the given combination of gates is equivalent to: A. NAND B. OR ( c . ) AND D. NOR |
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80 | The principle of LASER action involves: A. Amplification of particular frequency emitted by the system B. Population inversion c. Stimulated emission D. All of the above |
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81 | To reverse bias a photo-diode: A. cathode of the detector is set at a higher electric potential than the anode. B. anode of the detector is set at a higher electric potential than the cathode. C. cathode and anode are set at the same electric potential. D. none of the above. |
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82 | 59. For the given combination of gates , if the logic states of inputs A, B, C are as follows A = B = C = 0 and A =B=1, C = 0, then the logic states of output D are B (a) 0,0 (c) 1,0 (b) 0,1 (d) 1,1 al |
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83 | State whether given statement is True or False
The majority charge carriers in ( p ) -type semiconductor are electrons. |
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84 | A potential barrier V volts exists across a P-N junction. The thickness of the depletion region is ‘d’. An electron with velocity ‘v’ approaches P-Njunction from N-side. Find the velocity of the electron crossing the junction. |
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85 | The band gaps of a conductor, semiconductor and insulator are respectively ( boldsymbol{E} boldsymbol{g}_{1}, boldsymbol{E} boldsymbol{g}_{2} ) and ( boldsymbol{E} boldsymbol{g}_{3} . ) The relationship between them can be given as. A ( . E g_{1}=E g_{2}=E g_{3} ) в. ( E g_{1}<E g_{2}E g_{2}>E g_{3} ) D. ( E g_{1}E g_{3} ) |
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86 | For a common emitter amplifier, current gain is ( 60 . ) If the emitter current is ( 6.6 m A ), the base current is ( mathbf{A} cdot 1.08 mathrm{mA} ) B . ( 10.8 mathrm{mA} ) c. ( 0.108 m A ) D. ( 8.01 mathrm{mA} ) |
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87 | In a CE amplifier, the input ac signal to be amplified is applied across. A. Forward biased emitter-base junction B. Reverse biased collector-base junction c. Reverse biased emitter-base junction D. Forward biased collector-base junction |
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88 | A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is ( 250, R_{C}=1 k Omega ) and ( V_{C E} ) to reach saturation? A. ( 100 mu A ) B. ( 7 mu A ) ( c .40 mu A ) D. ( 10 mu A ) |
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89 | The efficiency of a full wave rectifier is? A. Half of half wave rectifier B. 3 times of half wave rectifier C. Double of half wave rectifier D. Same as half wave rectifier |
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90 | To achieve DC from ( A C, A C ) be applied across ( A cdot B D ) B. AC ( c ). ВС ( D cdot c D ) E. Al |
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91 | On increasing the reverse bias to a large value in a p-njunction, diode current A. Increases slowely B. Remains fixed c. suddenly increases D. Decreases slowly |
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92 | Barrier potential of a p-njunction diode does not depend on – A. diode design B. temperature c. forward bias D. doping density |
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93 | Reverse saturation current of a diode: A. is independent of temperature B. increases with increase in temperature C. decreases with increase in temperature D. may increase or decrease with increase in temperature depending on the semiconductor |
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94 | The process of converting alternating current into direct current is known as A. modulation B. amplification c. detection D. rectification |
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95 | Which of the following table helps in representing the previous and next of the sequential circuit prior to and after the clock pulse respectively? A. Truth table B. Characteristic table c. Excitation table D. None of the above |
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96 | What is forward biasing and reverse biasing of a diode? | 12 |

97 | The determines how electrons respond to forces (via the concept of effective mass). A. electrostatic forces B. dispersion relation c. magnetic force D. lorentz force |
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98 | An AND gate is followed by a NOT gate in series. With two inputs ( boldsymbol{A} & boldsymbol{B} ), the Boolean expression for the out put ( Y ) will be : A. ( A . B ) B. ( A+B ) ( c cdot overline{A+B} ) D. ( overline{A . B} ) |
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99 | For a transistor, the current ratio ( boldsymbol{alpha}_{d c}= ) ( frac{69}{70} . ) The current gain ( beta_{d c} ) is ( mathbf{A} cdot 66 ) B. 67 ( c cdot 69 ) D. 71 |
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100 | ( boldsymbol{E}_{boldsymbol{g}}(boldsymbol{T})=boldsymbol{E}_{boldsymbol{g}}(boldsymbol{m})-frac{boldsymbol{alpha} boldsymbol{T}^{2}}{boldsymbol{T}+boldsymbol{beta}} ) is the Varshni’s empirical expression,then the value of ( m ) is |
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101 | If to an intrinsic semiconductor, a pentavalent element is added as impurity, one get extrinsic semi conductor of ( _{–}-_{-}- ) type A. n-type B. p-type C. intrinsic D. Both A and B |
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102 | The value of current in the above diagram is (diode assumed to be ideal one) A . 0 в. ( 1 A ) c. ( 1.66 A ) D. 15A |
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103 | LCD stands for: A. Light Carrying Diode B. Liquid Crystal Display C . Long Crystal Display D. Light Crystal Display |
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104 | A semiconductor is a material with a small but non-zero band gap that behaves as an insulator at absolute zero but allows thermal excitation of electrons into its temperatures that are below its melting point. A. номо B. valence band c. conduction band D. LUMO |
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105 | 44. In the circuit shown in the figure, the base current le 1S 10 uA and the collector is 5.2 mA. The value of VBE is RE 3 500 k22 13 lctlB Rc = 1 k12 + 5.5 V INCE T-vec -VBE (a) 0.1 V (c) 0.5 V (b) 0.3 V (d) 0.7 V |
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106 | Draw V-I characteristics of a p-n junction diode. Answer the following questions, giving reasons: (i) Why is the current under reverse bias almost independent of the applied upto a critical voltage? (ii) Why does the reverse current show a sudden increase at the critical voltage? Name any semiconductor device which operates under the reverse bias in the breakdown regions |
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107 | In an ( n ) -p-n transistor circuit, the collector current is ( 10 m A ). If ( 90 % ) of the electrons emitted reach the collector, then This question has multiple correct options A. the emitter current, the will be ( 9 m A ) B. the base current will be ( 1 m A ) c. the emitter current will be ( 11.11 m A ) D. The base current will be ( 1.11 mathrm{mA} ) |
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108 | toppr Q Type your question configuration is : ( A ) B. ( c ) ( D ) |
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109 | Which of the following gates corresponds to the truth table given below? ( A B Y ) [ begin{array}{ccc} 1 & 1 & 0 \ 1 & 0 & 1 \ 0 & 1 & 1 end{array} ] ( 0 quad 0 quad 1 ) A. xor в. ок c. NAND D. NOR |
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110 | In the valance band, the current is due to A. the presence of electrons B. the presence of holes c. the presence of both electrons and holes D. none of the above |
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111 | 70. A moving-coil ammeter is to be adapted to detect small alternating currents. Which of the following diagrams shows how a diode could be connected in order to make the conversion? |
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112 | Production of ICs is preferred in industrial scales because: A. it reduces the cost of production. B. it makes the task of fabrication of a circuit easier c. it improves the efficiency of the circuit. D. specifications of a circuit is same for all applications |
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113 | Of the diodes shown in the following diagrams, the reverse biased diode is ( mathbf{A} ) B. ( mathbf{c} ) D. |
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114 | In the Boolean algebra : ( boldsymbol{A}+boldsymbol{B}= ) A. ( bar{A}+bar{B} bar{hline} bar{B} ) в. А. c. ( overline{bar{A}}+overline{bar{B}} ) |
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115 | the intrinsic semiconductor at room temperature is |
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116 | In the case of forward biasing of a p-n junction diode,which one of the following figure correctly depicts the direction of conventional current? ( A ) ( B ) ( c ) ( D ) |
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117 | Which one of the following statements is not correct of for a junction transistor? A. The base region is very thin. B. Emitter is more heavily doped as compared to collector. c. Emitter and collector can be interchanged D. The surface area of collector is quite large as compared to emitter. |
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118 | You are given two circuits as shown in Fig., which consist of NAND gates. Identify the logic operation carried out by the two circuits. | 12 |

119 | At ( 0 K ) temperature, a p-type semiconductor A. has equal number of holes and free electrons B. has few holes but no free electrons c. has few holes and few free electrons D. does not have any charge carriers |
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120 | An oscillator is basically an amplifier with gain: A. Less than unity B. More than unity c. zero D. 0.5 |
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121 | Explain the formation of energy bands in solids. On the basis of energy bands distinguish between a metal, a semiconductor and an insulator. | 12 |

122 | The following symbol represents A. NAND gate B. NOT gate c. AND gate D. or gate |
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123 | For transistor action, which of the following statements are correct: This question has multiple correct options A. Base, emitter and collector regions should have similar size and doping concentrations B. The base region must be very thin and lightly doped C. The emitter junction is forward biased and collector junction is reverse biased D. Both the emitter junction as well as the collector junction are forward biased |
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124 | When a p-n-p transistor is operated in saturation region, then its A. Base-emitter junction is forward biased and basecollector junction is reverse biased. B. Both base-emitter and base-collector junctions are reverse biased C. Both base-emitter and base-collector junctions are forward biased D. Base-emitter junction is reverse biased and basecollector junction is forward biased. |
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125 | Which of the following pairs of semiconductor devices and the materials used don’t match? A. Solar cell : ( C u I n S e_{2} ) as absorber and ( C d S ) as collector B. LED:GaAs and AlGaAs c. optical fibre : Vitreous high silica glass doped with germanium D. Semiconductor Laser: NdYAG |
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126 | The attached figure shows the characteristics of: A. Zener diode B. Avalanche diode C. Photodiode D. LED |
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127 | Which of the following symbol represents a universal gate? ( A ) в. ( c ) D. |
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128 | In a common emitter transistor amplifier ( beta=60, R_{0}=5000 Omega ) and internal resistance of a transistor is 500Omega. The voltage amplification of amplifier will be A . 500 в. 460 c. 600 D. 560 |
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129 | 2. Two identical capacitors A and B are charged to the same potential V and are connected in two circuits at t = 0, as shown in figure. The charge on the capacitors at time t= CR are respectively R (a) VC, VC (b) C vc VC VC ) (0) VC vc |
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130 | Transistors used for making NOT gate.why? |
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131 | Energy band gap size for semiconductors is in the range ( e V ) ( mathbf{A} cdot 1-2 ) B. ( 2-3 ) ( mathbf{c} cdot 3-4 ) ( mathrm{D} cdot>4 ) |
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132 | Which of the following material(s) is/are used in making a solar cell? This question has multiple correct options A. Silicon B. Polycrystalline Thin Films c. Gallium Arsenide D. Both A and B |
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133 | 20. In the following circuit, the equivalent resistance between A and B is 2003 – 10 V d (b) 1032 (d) 2012 (c) 1692 |
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134 | Which among the following devices work on the basis of photo-voltaic effect?
This question has multiple correct options |
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135 | State whether given statement is True or False The ( p ) -n type junction can act as a semiconductor diode A. True B. False |
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136 | Which logic gate produces LOW output when any of the inputs is HIGH? A. AND в. ов c. NAND D. NOR |
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137 | Which one of the following represents forward bias diode? ( A ) в. ( c ) D. |
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138 | Conductors are materials having an electrical conductivity : A . greater than ( 10^{3} ) s/cm B. between ( 10^{-8} ) to ( 10^{3} ) s/cm C . equal to ( 10^{-8} mathrm{S} / mathrm{cm} ) D. zero |
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139 | A transistor has ( beta=40 . ) A change in base current of ( 100 mu ) A, produces change in collector current A. ( 40 times 100 m A ) в. ( (100-40) m A ) c. ( (100+40) m A ) D. ( 100 / 40 m A ) |
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140 | At absolute zero, a semiconductor is an insulator because A. No electron is present in the conduction band B. All electrons occupy the valence band C. The value of ( E_{G} ) is large D. All of the above |
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141 | Energy gap between valence band and conduction band of a semiconductor is A. Zero B. Infinite ( c cdot 1 e V ) D. 10 eV |
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142 | 3. In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be (a) 70.7 Hz (b) 100 Hz (c) 25 Hz (d) 50 Hz (AIEEE 2005) |
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143 | The electrical conductivity of a semiconductor increases when radiation of the wavelength shorter than ( 2480 n m ) is incident on it.The bandgap (in eV) for the semiconductor is A . 0.5 B. 0.9 ( c .0 .7 ) D. 1. |
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144 | Write down 5 difference between N-type and P-type semiconductors. | 12 |

145 | Give the circuit symbol of a diode. | 12 |

146 | In a solar cell current is generated due to bond breakage in which region? A. Depletion region B. n-region c. p-region D. None of these |
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147 | The circuit shown below is working as a ( 8 V ) de regulated voltage source. When ( 12 V ) is used as input, the power dissipated (in ( boldsymbol{m} boldsymbol{W} ) ) in each diode is; (considering both zener dioses are identical) |
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148 | The transducer used in television transmission works on the principle of A. Electromagnetic induction B. Photoelectric effect c. Raman’s effect D. Rayleigh’s effect |
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149 | A Zener diode is connected to a battery and a load as shown below: The current ( boldsymbol{I}, boldsymbol{I}_{Z} ) and ( boldsymbol{I}_{boldsymbol{L}} ) are respectively : A ( .12 .5 mathrm{mA}, 735 mathrm{mA}, 5 mathrm{mA} ) B. ( 12.5 mathrm{mA}, 5 mathrm{mA}, 7.5 mathrm{mA} ) c. ( 15 mathrm{mA}, 7.5 mathrm{mA}, 7.5 mathrm{mA} ) D. ( 15 mathrm{mA}, 5 mathrm{mA}, 10 mathrm{mA} ) |
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150 | 41. In question 38, the voltage gain of the amplifier is (a) 5 (b) 50 (c) 500 (d) 5000 |
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151 | Fermi energy level for intrinsic semiconductors lies A. At middle of the band gap B. Close to valence band c. close to conduction band D. None of the above |
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152 | Draw a diagram of show how NAND gates can be combined to obtain an OR gate.(Truth table is not required). | 12 |

153 | A germanium specimen is doped with aluminum. The concentration of acceptor atoms is ( 10^{21} ) atoms ( / m^{3} ). Given that the intrinsic concentration of electron-hole pairs is ( 10^{19} / m^{3}, ) the concentration of electrons in the specimen is A ( cdot 10^{17} / m^{3} ) В. ( 10^{15} 5 m^{3} ) c. ( 10^{4} / m^{3} ) D. ( 10^{3} / m^{3} ) |
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154 | With what considerations in view, a photodiode is fabricated? State its working with the help of a suitable diagram. |
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155 | ( boldsymbol{alpha}=mathbf{0 . 9 9} ) for a CE transistor amplified circuit. The input resistance is equal to ( 1 mathrm{K} Omega ) and load resistance is equal to 10 K ( Omega . ) The voltage gain of the circuit is A . 99 в. 990 c. 9900 D. 99000 |
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156 | LASER is an acronym for light amplification by A. Stimulated energetic radiation B. Spontaneous emission of radiation c. Stimulated emission of radiation D. Spontaneous emission of radio waves |
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157 | In p-njunction, avalanche current flows in circuit when biasing is A. forward B. reverse c. zero D. excess |
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158 | 58. The diagram shows a logic network. 8 NANDO YAND NAND NOT AND NANDO NOT Which single gate is equivalent to the network? (a) EX-NOR (b) NOR (c) EX-OR (d) OR son 1 |
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159 | In a common -base amplifier, the phase difference between the input signal voltage and output voltage is : A ( cdot frac{pi}{4} ) в. ( pi ) c. 0 D. |
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160 | If a signal passing through a gate is inhibited by sending a LOW into one of the inputs, and the output is HIGH, the gate is ( a(n) ) A. AND B. NAND c. NOR D. or |
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161 | What is rectification? Draw the circuit diagram of half wave rectifier and explain its working. Show the input ac voltage and output voltage waveforms from the rectifier circuit. |
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162 | Current in the circuit will be ( A cdot frac{5}{A 0} ) ( B cdot frac{5}{50} A ) ( c cdot frac{5}{10} A ) ( D cdot frac{5}{20} A ) |
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163 | What is rectification? Explain the working of a full-wave rectifier with a diagram. What is a zener diode? How will a zener diode be connected in a circuit generally? |
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164 | Electrical conductivity of a semiconductor increases when em radiation of ( lambda<2480 n m ) is incident on it. The band gap in (ev) for the semiconductor is ( mathbf{A} cdot 1.1 e V ) B . ( 2.5 e V ) c. ( 0.7 e V ) ( mathbf{D} cdot 0.5 e V ) |
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165 | The intrinsic semi conductor becomes an insulator at ( mathbf{A} cdot 0^{circ} C ) в. ( 0 K ) c. ( 300 K ) D. ( -100^{circ} mathrm{C} ) |
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166 | Number of electrons in the valence shell of a semiconductor is A . B. 2 ( c .3 ) ( D ) |
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167 | For both pure and doped silicon, calculate the probability that a state at the bottom of the silicon conduction band is occupied? ( A cdot 5.20 times 10^{-2} ) B . ( 1.40 times 10^{-2} ) c. ( 10.5 times 10^{-2} ) D. ( 14 times 10^{-2} ) |
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168 | In the case of p-njunction diode at a high value of reverse bias, the current rises sharply. The value of reverse bias is known as A. cut off voltage B. zener voltage c. inverse voltage D. critical voltage |
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169 | To obtain p-type Si semiconductor, we need to dope pure Si with A. Aluminium B. Phosphorous c. oxygen D. Germanium |
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170 | The space-charge region on either side of the junction together is known as depletion region because A. neither electrons nor holes exist in this region B. the electrons and holes taking part in the initial movement across the junction freed the region of its free charges. c. the electrons and holes in this region are immobile D. None of these |
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171 | (a) NAND gates are also called universal gate. Why? (b) Draw a logic symbol of OR gate. (c) Write the value of output ( y ) in the given circuit: (d) Write the name of the diode used in voltage regulation. Input ( a=1-square ) output ( y ) |
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172 | The level formed due to impurity atom, in the forbidden energy gap, very near to the valence band in a P-type semiconductor is called A. an acceptor level B. a donor level c. a conduction level D. none of these |
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173 | Write the name of device ( ^{prime} X^{prime} ) in the following given diagram. Explain its working making its circuit diagram. |
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174 | A diode having potential difference ( 0.5 V ) across its junction which does not depend on current, is connected in series with resistance of ( 20 Omega ) across source. If ( 0.1 A ) current passes through resistance then what is the voltage of the source? A. ( 1.5 V ) в. ( 2.0 V ) ( mathrm{c} .2 .5 mathrm{V} ) D. ( 5 V ) |
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175 | The reverse saturation current of a silicon diode A. doubles for every ( 10^{circ} mathrm{C} ) increase in temperature B. does not change with temperature C. halves for every ( 1^{circ} mathrm{C} ) decrease in temperature D. increases by 1.5 times for every ( 2^{circ} C ) increment in temperature |
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176 | Write he name of any one doped semiconductor used for making light emitting diode (LED) | 12 |

177 | A point light source are located at ( P_{1} ) as shown in the figure in which all sides of the polygon are equal. The intensity of illumination at ( P_{2} ) is ( 8 frac{W}{m^{2}}, ) what will be the intensity of illumination at ( P_{3} ) A ( cdot 3 sqrt{3} frac{W}{m^{2}} ) в. ( 6 frac{W}{m^{2}} ) с. ( _{8^{2}} frac{W}{^{2}} ) D. ( sqrt{3} frac{w}{m^{2}} ) |
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178 | If a full wave rectifier circuit is operating from ( 50 H z ) mains, the fundamental frequency in the ripple will be ( mathbf{A} cdot 25 H z ) B. ( 50 mathrm{Hz} ) c. ( 70.7 mathrm{Hz} ) D. ( 100 H z ) |
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179 | LEDs have the following advantages over conventional incandescent low power lamps: A. Long life and ruggedness B. Low operational voltage and less power c. Fast on-off switching capability, D. All of the above |
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180 | Which of the following logic gates is an universal gate? A. or в. NOT c. AND D. NAND |
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181 | Boolean relation at the output stage- ( boldsymbol{Y} ) for the following circuit is: A ( . bar{A}+bar{B} ) в. ( A cdot B ) ( c cdot bar{A} cdot bar{B} ) D. ( A+B ) |
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182 | Which of the following is/are optoelectronic devices? A. photodiodes B. solar cells c. light emitting diodes D. all of the above |
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183 | Which of the following is/are true regarding breakdown voltage of Zener diode? A. If the reverse bias voltage across a p-njunction diode is increased, at a particular voltage the reverse current suddenly decreases to a large value B. The holes in the n-side and the conduction electrons in the p-side are accelerated due to the reverse bias voltage. C. The voltage at which the rate of creation of holeelectron pairs is increased leading to the increased current is called avalanche breakdown D. None of the above |
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184 | The output Y of the gate circuit shown in the fig is ( mathbf{A} cdot bar{A}+bar{B} ) B. ( overline{A+bar{B}} ) ( c cdot overline{A+B} ) ( D cdot A+B ) |
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185 | The following truth table is for which gate? ( begin{array}{lll}A & B & Y=A+B \ 0 & 0 & 0 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 1end{array} ) A. AND B. OR c. Nor D. NAND |
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186 | Explain the working of a common base transistor amplifier with the help of a circuit diagram. The load resistance of output circuit is ( 600 k Omega ) and resistance of input circuit is ( 150 p Omega ) in a common base amplifier. If current amplification is ( 0.90, ) then calculate the voltage amplification. |
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187 | Calculate the probability that a donor state in the doped material is occupied? A. 0.824 B. 0.08 c. 0.008 D. 8.2 |
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188 | Box 72. A semiconductor diode and a resistor of constant resistance are connected in some way inside a box having two external terminals. When a potential difference V of 1 Vis applied, I = 25 mA. If potential difference is reversed, I = 50 mA. Forward resistance and diode resistance are (a) 40 2,20 22 (b) 40 2,40 12 (c) 0 12, (d) 622, 12 22 |
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189 | 3. A doped semiconductor has impurity levels 30 meV below the conduction band. In a thermal collision, an amount kT of energy is given to the extra electron loosely bound to the impurity of ion. This electron just manages to be in the conduction band. The value of temperature T is (a) 3 K (b) 34 K (c) 34.8 K (d) 348 K |
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190 | The output of an AND gate is connected to both the inputs of a NOR gate, then this circuit will act as a A. or gate B. NOR gate c. AND gate D. NOT gate E. NAND gate |
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191 | w.”15 ivsiv circuit is ( A ) B. [ left|begin{array}{lll} A & B & Y \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 1 end{array}right| ] ( c ) ( D ) |
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192 | The circuit given represents which of ( log i c ) operations A. AND B. NOT ( c . ) ов D. NOR |
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193 | Optoelectronic devices work on: A . light B. electrical current c. both ( A ) and ( B ) D. none of the above |
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194 | The distinction between conductors, insulators and semiconductors is largely concerned with A. their ability to conduct current B. the type of crystal lattice c. binding energy of their electrons D. relative widths of their energy gaps |
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195 | In a sample of semi conductor mobilities of electrons and holes are ( 24 times 10^{3} c m^{2} V^{-1} S^{-2} ) and ( 0.2 times ) ( 10^{3} mathrm{cm}^{2} V^{-1} S^{-1} ) respectively. If the density electrons is ( 0.8 times 10^{14} mathrm{cm}^{-3} ) and that of holes is ( 0.4 times 10^{14} mathrm{cm}^{-3} ) Find the nature of semi conductor and its conductivity |
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196 | (A) What do you mean by barrier potential of diode? (B) With help of a diagram explain the working of a full wave rectifier. |
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197 | Let ( n_{p} ) and ( n_{e} ) the number of holes and conduction electrons in an intrinsic semiconductor. Then: A ( cdot n_{p}>n_{e} ) в. ( n_{p}=n_{e} ) c. ( n_{p}<n_{e} ) D ( cdot n_{p} neq n_{e} ) |
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198 | Identify the gate and match ( A, B, Y ) in bracket to check. ( mathbf{A} cdot operatorname{AND}(A=1, B=1, Y=1) ) B. OR ( (A=1, B=1, Y=0) ) C . NOT ( (A=1, B=1, Y=1) ) D. XOR ( (A=0, B=0, Y=0) ) |
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199 | On increasing the reverse bias to a large value in p-njunction diode then value of current A. remain fixed B. increases slowly c. decreases slowly D. suddenly increases |
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200 | What is a rectifier? With a suitable circuit diagram, describe the action of a full wave rectifier by drawing input and output waveforms. |
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201 | toppr ( E ) Q Type your question. 0 ( A ) ( begin{array}{lll}A & B & Y \ 0 & 0 & 1end{array} ) 010 101 в. ( A B cdot Y ) ( 0 quad 0 quad 1 ) 0.11 101 c. ( A B Y ) 00 011 101 110 D. ( A B Y ) 00.1 011 |
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202 | The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is ( 6 V ) and the load resistance is ( R_{L}=4 k Omega . ) The series resistance of the circuit is ( R_{i}=1 k Omega . ) If the battery voltage ( V_{B} ) varies from ( 8 V ) to ( 16 V ), what are the minimum and maximum values of the current through Zener diode? A. ( 0.5 mathrm{mA} ; 6 mathrm{mA} ) B. ( 0.5 mathrm{mA} ; 8.5 mathrm{mA} ) c. ( 1.5 m A ; 8.5 m A ) D. ( 1 mathrm{mA} ; 8.5 mathrm{mA} ) |
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203 | State whether given statement is True or Falsel n p-njunction diode, the current in the reverse biased junction is generally very small A. True B. False |
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204 | AND gate A. it has no equivalence to switching circuit. B. it is equivalent to series switching circuit. C. it is equivalent to parallel switching circuit D. it is a mixture of series and parallel switching circuit. |
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205 | 2. The electrical conductivity of a semiconductor increases when electromagnetic radiations of wavelength shorter than 2480 nm is incident on it. The band gap (in eV) for the semiconductor is (a) 0.7 eV (b) 0.5 eV (c) 0.6 eV (d) 1.1 eV (AIEEE 2005) |
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206 | LEDs are better than conventional incandescent power lamps because: A. LEDs have higher efficiency. B. LEDs look beautiful. c. LEDs are cheap. D. all of the above |
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207 | Two triodes having amplification factors 30 and 21 and plate resistances ( 5 k Omega ) and ( 4 k Omega ) respectively are connected in parallel. The composite amplification factor of the system is A . 25 B . 50 c. 75 D. 100 |
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208 | The ( V-I ) characteristic of a silicon diode is shown in the figure. Calculate the resistance of the diode at (a) ( I_{D}=15 m A ) and (b) ( V_{D}=-10 V ) |
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209 | 7. In the following circuits, PN-junction diodes D1, D2 and D3 are ideal for the following potential of A and B. The correct increasing order of resistance between A and B will be DR 5.795 (ii) – 5V, – 10 V (i) – 10 V, -5V (iii) – 4V, – 12V (a) (i) < (ii) < (iii) (c) (ii) = (iii) < (i) (b) (iii) <(ii) < (i) (d) (i) = (iii) < (ii) |
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210 | Draw a circuit diagram of a full wave rectifier. Explain its working and draw input and output waveforms. | 12 |

211 | In a common emitter (CE) amplifier having a voltage gain ( G, ) the transistor used has transconductance 0.03 mho and current gain ( 25 . ) If the above transistor is replaced with another one with transconductance 0.02 mho and current gain ( 20, ) the voltage gain will be A ( cdot frac{2}{3} G ) в. ( 1.5 G ) c. ( frac{1}{3} G ) D. ( frac{5}{4} G ) |
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212 | Currents flowing in each of the following circuits ( A ) and ( B ) respectively are ( A cdot 1 A, 2 A ) B. 2 A, 1 A ( c cdot 4 A, 2 A ) D. 2 A, 4 A |
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213 | In a zener-regulated power supply a zener diode with ( V_{z}=6 ) volt is used for regulation. The load current is to be ( 4 m A ) and the unregulated input is 10 volt. What should be the value of series resistor ( boldsymbol{R}_{s} ) if the current through diode is five times the load current? |
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214 | In a semiconductor, the forbidden energy gap between the valence band and the conduction band is of the order is A . ( 1 mathrm{MeV} ) B. ( 0.1 mathrm{MeV} ) c. ( 1 e V ) D. ( 5 e V ) |
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215 | Symbolic representation of NOR gate is? ( A ) в. ( c ) D. |
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216 | The logic circuit in the figure represents characteristics of which logic gate? A . NOR B. OR c. NAND D. NOT |
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217 | Ciascu 65. A capacitor is to be used to provide smoothing for a half wave rectifier. In which of the following diagrams is the capacitor correctly connected? Load = Load Load Load |
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218 | What is an energy gap? A. the space between two orbital shells B. the energy equal to the energy acquired by an electron passing a ( 1 V ) electric field C. the energy band in which electrons can move freely D. an energy level at which an electron can exist |
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219 | An increase in temperature produces A. an increase in the minority carrier current B. an decrease in the minority carrier current C. an increase in the majority carrier current D. no carrier current |
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220 | dentify the operation performed by the circuit given below: A . NOT B. AND ( c . ) ов D. NAND |
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221 | Which logic gates is represented by the following combination of logic gates? A. OR B. NAND c. AND D. NOR |
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222 | What is the number density of donor atoms which must be added to a pure germanium semiconductor to produce an N-type semiconductor of conductivity ( 6.4 X 10^{2} ) oh ( m^{-1} m^{-1} ) ? The mobility of electrons in N-type germanium is ( 4 X 10^{-1} m^{2} V^{-1} s^{-1} ) Neglect contribution of holes to conductivity. A ( cdot 10^{20} m^{-3} ) B. ( 10^{21} m^{-3} ) ( mathrm{c} cdot 10^{22} mathrm{m}^{-3} ) D. ( 10^{23} ) s ( ^{-3} ) |
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223 | What is photo diode? Mention its one use. |
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224 | 13. This question has Statement I and Statement II. Of the four choices given after the statements, choose the one that best describes the two statements. Statement I: Higher the range, greater is the resistance on ammeter. Statement II: To increase the range of ammeter, additional shunt needs to be used across it. (a) Statement I is true, statement II is true, statement II is not the correct explanation of statement I. (b) Statement I is true but statement II is false. (c) Statement I is false but statement II is true. (d) Statement I is true but statement II is true, statement II is the correct explanation of statement I (JEE Main 2013) |
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225 | What is the depletion region in pn junction? |
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226 | The combination of the gates shown below produces where ( G_{1} ) to ( G_{4} ) are NOR gates: A. AND gate B. xoR gate c. NOR gate D. NAND gate |
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227 | 150 2 5092 12. The circuit shown in the following figure contains two diodes, each with a forward resistance of 50 and with infinite backward resistance. If the battery voltage is 6V, the current through 100 12 resistance (in amperes) is: (a) Zero (b) 0.02 (c) 0.03 (d) 0.036 1002 |
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228 | 39. In question 38, the ac current gain is (a) o (b) 1 (c) 0.1 (d) 10000 |
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229 | Zener diodes with breakdown voltage ranging over ( 2 mathrm{V}-200 mathrm{V} ) are commercially available. Breakdown voltage of a zener diode A. Increases with increasing doping concentration B. Decreases with increasing doping concentration C. Does not depend on doping concentration D. May increases or decreases with increasing doping concentration |
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230 | A red LED emits light at ( 0.1 W ) uniformly around it. The amplitude of the electric filed of the light at a distance of ( 1 ~ m ) form the diode is: A. ( 1.73 mathrm{V} / mathrm{m} ) в. ( 2.45 mathrm{V} / mathrm{m} ) c. ( 5.48 mathrm{V} / mathrm{m} ) D. ( 7.75 V / m ) |
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231 | Which of the following elements is added to turn artificial diamond into semi conductors? A. Beryllium B. Boron c. Magnesium D. Calcium |
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232 | The grid voltage of any triode valve is changed from -1 volt to -3 volt and the mutual conductance is ( 3 times 10^{-4} ) mho. The change in plate circuit current will be A. ( 0.8 mathrm{mA} ) B. ( 0.6 mathrm{mA} ) c. ( 0.4 mathrm{mA} ) D. ( 1 mathrm{m} ) |
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233 | The highest occupied energy band is called and lowest unoccupied energy band is called the A. Band Gap, conduction band B. Valence band, Band Gap c. conduction band, valence band D. valence band, Conduction band |
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234 | What is a hole? Which type of doping creats a hole? |
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235 | In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of A. ( 1 mathrm{MeV} ) B. ( 0.1 mathrm{MeV} ) c. ( 1 e V ) D. ( 5 e V ) |
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236 | What is true about the breakdown voltage in a zener diode? A. It decreases when current increases. B. It destroys the diode. c. It equals the current times the resistance. D. It is approximately constant. |
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237 | DU 6. In the circuit given below, V(t) is the sinusoidal voltage source, voltage drop Var(t) across the resistance R ZVAB R; = 100 1 R2 = 150 12 (a) is half wave rectified (b) is full wave rectified (c) has the same peak value in the positive and negative half cycles (d) has different peak values during positive and negative half cycle |
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238 | A zener diode is rated as ( 1 W, ) if given breakdown voltage is ( 6.2 V ) then max current it can hold is A ( .224 m A ) в. ( 161 m A ) ( mathrm{c} .239 mathrm{mA} ) D. none of the above |
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239 | A 5 V zener diode is used to regulate the voltage across load resistor ( boldsymbol{R}_{L} ) and the input voltage varies in between ( 10 mathrm{V} ) to ( 15 mathrm{V} . ) The load current also varies from 5 ( mathrm{mA} ) to ( 50 mathrm{mA} ). Find the value of series resistance R. Given, ( boldsymbol{I}_{Z}(boldsymbol{m} boldsymbol{i} boldsymbol{n})=boldsymbol{2} boldsymbol{0} boldsymbol{m} boldsymbol{A} ) A . ( 70 Omega ) B. ( 90.91 Omega ) c. ( 142.86 Omega ) D. ( 71.43 Omega ) |
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240 | The forbidden energy gap for germanium crystal at ( 0 K ) is A. ( 0.071 e V ) в. ( 0.71 e V ) c. ( 2.57 e V ) D. ( 6.57 e V ) |
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241 | toppr Q Type your question ( A ) 3 ( c ) ( D ) |
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242 | Assertion The logic gate NOT can be built using diode Reason The output voltage and the input voltage of the diode have ( 180^{circ} mathrm{C} ) phase difference. 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 |
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243 | Write the truth table for circuit given in the figure, consisting of NOR gates and identify the logic operation (OR, AND, NOT) which this circuit is performing. (Hint: ( A=0, B=1 ) then ( A ) and ( B ) inputs of second NOR gate will be 0 and hence ( Y=1 . ) Similarly work out the values of ( Y ) for other combinations of ( A ) and ( B ). Compare with the truth table of OR, AND, NOT gates and find the correct one). |
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244 | In insulators (CB is conduction band and VB is valence band) A. VB is partially filled with electrons B. CB is partially filled with electrons c. ( mathrm{cB} ) is empty and ( mathrm{VB} ) is filled with electrons D. CB is filled with electrons and VB is empty |
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245 | One among the following is doping material in p-type of semiconductor: A. carbon B. Indium c. Arsenic D. Phosphorous |
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246 | The junction diode shown in the figure is ideal. The current in the circuit is A ( .20 m A ) B. ( 2 m A ) ( c .200 m A ) D. 200 A |
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247 | What will be the current flowing through the ( 6 K Omega ) resistor in the circuit shown where the breakdown voltage of the zener is ( 6 mathrm{V} ) ? A ( cdot frac{2}{3} mathrm{mA} ) B. 1mA c. ( 10 mathrm{mA} ) D. ( frac{3}{2} mathrm{mA} ) |
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248 | A transistor having ( alpha=0.99 ) is used in common base amplifier. If the load resistance is ( 0.45 M Omega ) and the dynamic resistance of the emitter junction is ( mathbf{5 0} mathbf{Omega}, ) the voltage gain of the amplifier will be A .7910 0 в. 8910 ( c .9910 ) D. 6910 |
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249 | For PN junction, the intensity of electric field is ( 1 times 10^{6} mathrm{V} / mathrm{m} ) and the width of depletion region is 5000 A. The value of potential barrier= V. A . 0.05 B. 0.005 ( c .0 .5 ) D. 5 |
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250 | Integrated circuits are preferred over conventional circuits because: A. They are very compact in size. B. They are cheap. c. They are fast and more efficient. D. All of the above |
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251 | In the Boolean algebra, the following one is wrong A ( .1+0=1 ) B. ( 0+1=1 ) c. ( 1+1=1 ) D. ( 0+0=1 ) |
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252 | In a silicon diode, the reverse current increases from ( 10 mu A ) to ( 20 mu A ). when the reverse voltage change from ( 2 V ) to ( 4 V ) The reverse ac resistance of the diode is A ( cdot 1 times 10^{5} Omega ) В. ( 3 times 10^{5} Omega ) c. ( 2 times 10^{5} Omega ) D. ( 4 times 10^{5} Omega ) |
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253 | The following configuration of gates is equivalent to A. xon B. NAND ( c . ) ок D. None of these |
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254 | Identify the gate. | 12 |

255 | 56. Identify the gate in the figure. (a) AND (c) NOR (b) XOR (d) NAND |
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256 | Among the following, the wrong statement in the case of semiconductor is: A. Resistivity is in between that of a conductor and insulator B. Temperature coefficient of resistance is negative c. Doping increases conductivity. D. At absolute zero temperature, it behaves like a conductor |
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257 | In a p-njunction photo cell, the value of the photo electromotive force produced by monochromatic light is proportional to A. the barrier voltage at the p-njunction. B. the intensity of the light falling on the cell. C. the frequency of the light falling on the cell. D. the voltage applied at the p-n junction. |
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258 | The current gain of transistor in a common emitter circuit is ( 40 . ) The ratio of emitter current to base current is ( mathbf{A} cdot 40 ) B. 41 c. 42 D. 43 |
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259 | If the forward bias on p-njunction is increased from zero to ( 0.045 V ), then no current flows in the circuit. The contact potential of junction i.e. ( V_{B} ) is A. zero B. ( 0.045 V ) C. more than ( 0.045 V ) D. less than ( 0.045 V ) |
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260 | Why are NOR gates considered as universal gates? |
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261 | State whether given statement is True or False
The probability of electrons to be found in the conduction band of an intrinsic |
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262 | What is meant by amplification? Draw a simple circuit of ( n ) -p-n common emitter transistor amplifier. On the basis of band theory, distinguish between conductor, insulator and semi- conductor. |
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263 | If an intrinsic semiconductor is heated, the ratio of free electrons to holes is : A. greater than one B. less than one c. equal to one D. dercease and becomes zero |
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264 | In the circuit shown, what will be the current through the ( 6 V ) zener? ( mathbf{A} cdot 6 m A, ) from ( A ) to ( B ) B. ( 2 m A ), from A to ( B ) ( mathrm{c} .2 mathrm{mA}, ) from ( mathrm{B} ) to ( A ) D. Zero |
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265 | For a common emitter amplifier, current gain is ( 60 . ) If the emitter current is ( 6.6 ~ m A ) the collector current is : A. ( 0.108 mathrm{mA} ) B. 6.492 m ( A ) c. ( 1.1 mathrm{m} ) А D. 3.3 ( m A ) |
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266 | biased has a drop of ( 0.5 % ) which is assumed to be independent of current. The current in excess of ( 10 m A ) through the diode produces large joule heating which damages the diode. If we want to use a ( 1.5 ~ V ) battery to forward bias the diode, the resistor used in series with the diode so that the maximum current does not exceed ( 5 m A ) is A ( .2 times 10^{2} Omega ) B . ( 2 times 10^{5} Omega ) C ( cdot 2 times 10^{3} Omega ) D . ( 2 times 10^{4} Omega ) |
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267 | What is the voltage gain in a common emitter amplifier, when input resistance is ( 3 Omega ) and load resistance is ( 24 Omega ) with ( beta=60 ? ) A. 480 в. 2.4 ( c .4 .8 ) D. 8.4 |
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268 | A semiconductor has equal electron and hole concentration of ( 2 times 10^{8} m^{-3} ) On doping with a certain impurity, the electron concentration increases to ( 4 x ) ( 10^{10} m^{-3}, ) then the new hole concentration of the semiconductor is A ( cdot 10^{6} m^{-3} ) B . ( 10^{8} m^{-3} ) D. ( 10^{12} m^{-3} ) |
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269 | Mention the important considerations required while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED).What should be the order of band gap of an LED if it is required to emit light in the visible range? |
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270 | The Fermi level in intrinsic semi- conductors at ( 0 K ) temperature lies: A. Near the conduction band B. Near the valence band C. In the middle of valence and conduction band D. Inside the conduction band |
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271 | The majority charge carriers in the emitter of an NPN transistor are A. pentavalent atoms B. trivalent atoms c. electrons D. holes |
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272 | If ( boldsymbol{A}=mathbf{1}, boldsymbol{B}=mathbf{0} ) then the value of ( overline{boldsymbol{A}}+boldsymbol{B} ) in terms of Boolean algebra is A . ( A ) в. ( B ) c. ( B+A ) D. A.B |
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273 | Generally semiconductor can be used safely between the temperatures: A . -75 and 200 B. 0 and 75 c. -25 and 300 D. -40 and 1000 |
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274 | When an impurity is doped into semiconductor, the conductivity of the semiconductor A . increases B. decreases c. remains same D. becomes zero |
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275 | The voltage at ( B ) in the figure is : ( A cdot 5.3 V ) В. ( 5.7 V ) ( c .6 .3 V ) D. ( 6 V ) |
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276 | The energy gap in glass at room temperature is A. Greater than that in a semiconductor. B. Less than that in a good conductor C. Greater than that in a good conductor. D. Both (1) and (3) are true. |
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277 | Choose the correct statement: A. A p-type semiconductor is positively charged B. The Boolean expression ( 1 cdot 0=0 ) C. The majority carrier in ( N ) – type semiconductor is hole D. A transistor cannot be used as a switch |
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278 | In insulator A. valence band is partially filled with electrons B. conduction band is partially filled with electrons c. conduction band is filled with electrons and valence band is empty D. conduction band is empty and valence band is filled with electrons |
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279 | Constant DC voltage is required from a variable AC voltage. Which of the following is correct order of operation? A. Regulator, Filter, Rectifier B. Rectifier, Regulator, Filter c. Rectifier, Filter, Regulator D. Filter, Regulator, Rectifier |
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280 | When a p-n diode is reverse biased, then A. no current flows B. the depletion region is increased C. the depletion region is reduced D. the height of the potential barrier is reduced |
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281 | 22. The reading of the ammeter for a silicon diode in the given circuit is 2002 (a) 13.5mA (c) 15 mA (b) 0 (zero) (d) 11.5 mA (JEE Main 2018) |
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282 | You are given the two circuits as shown In Fig. Show that circuit (a) acts as OR gate while the circuit (b) acts as AND gate. |
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283 | Which is not true: A. Resistance of metals increases with increasing temperature B. Resistance of semi-conductors decreases with rise of temperature C. Resistance of an electrolyte increases with rise of temperature D. None of the above |
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284 | Identify the semiconductor devices whose characteristics are given above in the order ( (a),(b),(c),(d): ) (a) ( (b) ) ( (c) ) A. Simple diode, Zener diode, Solar cell, Light dependent resistance B. Zener diode, Simple diode, Light dependent resistance, Solar cell C. Solar cell, Light dependent resistance, Zener diode Simple diode D. Zener diode, Solar cell, Simple diode, Light dependent resistance |
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285 | In Boolean algebra, ( boldsymbol{A}+boldsymbol{B}=boldsymbol{Y} ) implies that A. sum of ( A ) and ( B ) is ( Y ). B. ( Y ) exists when ( A ) exists or ( B ) exists or both ( A ) and ( B ) exist c. ( Y ) exists only when ( A ) and ( B ) both exist D. ( Y ) exists when ( A ) or ( B ) exist but not when both ( A ) and ( B ) exist |
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286 | ( h ) | 12 |

287 | Calculate the number of states per cubic metre of sodium in 3 s band. The density of sodium is 1013 kgm ( ^{-3} ). How many of them are empty? |
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288 | In semiconductors, at a room temperature A. the valence band is partially empty and the conduction band is partially filled. B. the valence band is completely filled and the conduction band is partially filled. C. the valence band is completely filled. D. the conduction band is completely empty. |
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289 | If collector current is ( 120 m A ) and base current is ( 2 m A ) and resistance gain is 3 what is power gain? A . 180 B. 10800 c. 1.8 D. 18 |
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290 | An n-type semiconductor is A. Positively charged B. Negatively charged C . Electrically neutral D. None of the above |
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291 | An electrical device which offers a low resistance to the current in one direction but a high resistance to the current in opposite direction is: A. Current Amplifier B. Oscillator c. Power Amplifier D. Rectifier |
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292 | 67. In a common-emitter amplifier, using output resistance of 5000 ohm and input resistance of 2000 ohm, if the peak value of input signal voltage is 10 mV and B = 50, then the peak value of output voltage is (a) 5 x 100 V (b) 2.5 x 104 v (c) 1.25 V (d) 125 V |
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293 | In Boolean algebra ( boldsymbol{A} . boldsymbol{B}=boldsymbol{Y} ) implies that: A. product of ( A ) and ( B ) is ( Y ) B. ( Y ) exists when ( A ) exists or ( B ) exists c. ( Y ) exists when both ( A ) and ( B ) exist but not when only ( A ) or ( B ) exists D. ( Y ) exists when ( A ) or ( B ) exists but not both ( A ) and ( B ) exist |
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294 | opp Q Type your question 3 ( c ) ( D ) |
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295 | Depletion layer consists of: A. electrons B. protons c. mobile ions D. immobile ions |
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296 | Fill in the blanks. During reverse bias of the diode there is a small current of the order of micro ampere due to |
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297 | Which are the areas influenced by electronics? |
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298 | To use a transistor as an amplifier: A. The emitter base junction is forward biased and the base collector junction is reverse biased B. No bias voltage are required C. Both junctions are forward biased D. Both junction are reverse biased |
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299 | The saturation condition of transistor implies that A. Collector current has highest possible value B. entire ( V_{c c} ) gets dropped across load resistor C. it acts as a closed switch with negligible value of resistance D. all of the above |
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300 | The collector supply voltage in ( mathrm{CE} ) transistor amplifier is ( 10 V . ) The base current is ( 10 mu A ) in the absence of the signal voltage and the voltage between the collector and the emitter is ( 4 V ). The current gain ( (beta) ) of a transistor is 200 then the value of the load resistance ( boldsymbol{R}_{boldsymbol{L}} ) ( mathbf{A} cdot 2 k Omega ) в. ( 1 k Omega ) ( c .3 k Omega ) D. ( 4 k Omega ) |
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301 | Calculate the current through the given circuit. (The diodes are ideal) ( 4.6 mathrm{A} ) B. 12 A ( c cdot 1 A ) 2 |
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302 | From the adjacent circuit, the output voltage is ( mathbf{A} cdot 10 V ) B. ( 100 V ) ( mathrm{C} cdot 90 mathrm{V} ) D. zero |
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303 | Use of ICs has lead to an increase in speed of PCs. Current processor speeds in personal computers is of the order of: A. ( k H z ) B. ( M H z ) ( mathrm{c} . G H z ) D. ( T H z ) |
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304 | The device that can act as a complete electronic circuit is – A. Junction diode B. Integrated circuitt c. Junction transistor D. zener diode |
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305 | The forward characteristic curve of a junction diode is shown in Figure. Calculate the resistance of the diode at: (1) ( V=0.5 V ) (2) ( mathrm{I}=60 mathrm{mA} ) |
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306 | Choose the correct option: Electrical conductivity of a semi conductor- A. decreases with rise in its temperature. B. increases with rise in its temperature. c. does not changes with temperature. D. first decreases and then increases with rise in temperature. |
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307 | Which of the following is unipolar transistor? A . p-n-p transistor B. n-p-n transistor C. Field effect transistor D. Point contact transistor |
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308 | State the difference between laser light and ordinary light | 12 |

309 | An oscillator is nothing but an amplifier with A. Positive feedback B. Large gain c. No feedback D. Negative feedback |
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310 | If the output ( Y ) of the following circuit is 1, the inputs ( A B C ) must be : A .010 В. 100 ( c .101 ) D. 110 |
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311 | The band structure determines the conductive behaviour of a solid. A. True B. False |
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312 | The truth table for NOT gate is ( A ) [ left[begin{array}{ll} 1 & 1 \ 0 & 0 end{array}right] ] B. [ left[begin{array}{ll} 1 & 0 \ 0 & 0 end{array}right] ] c. [ left[begin{array}{ll} 1 & 0 \ 0 & 1 end{array}right] ] D. [ left[begin{array}{ll} 0 & 1 \ 1 & 1 end{array}right] ] |
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313 | What is a transistor? Mention any two uses of transistor. |
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314 | The avalanche breakdown in ( p-n ) junction is due to A. shift of Fermi level. B. cumulative effect of conduction band electron c. widening of forbidden gap. D. high impurity concentration. |
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315 | The forward biased diode connection is: ( A ) B. c. D. |
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316 | Explain, with the help of a circuit diagram, the working to a photo-diode. Write briefly how it is used to detect the optical signals. OR Mention the important considerations required while fabricating a ( boldsymbol{p}-boldsymbol{n} ) junction diode to be used as a Light Emitting Diode (LED). What should be the order of band gap of an LED if it is required to emit light in the visible range? |
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317 | At absolute zero temperature a semiconductor behaves like: A. an insulator B. a super conductor c. a good conductor D. a variable resistor |
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318 | Identify the logic gate whose truth table is given below and draw its symbol: ( begin{array}{ccc}boldsymbol{A} & boldsymbol{B} & boldsymbol{Y} \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0end{array} ) |
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319 | Assertion Photodiode and solar cell work on same mechanism. Reason Area is large for solar cell. 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 |
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320 | IR 71. Figure shows a piece of semiconductor (pure one) S in series with a variable resistor R and a source of constant voltage V. S is heated and the current is kept constant by adjustment of R. Which of the following factors will decrease during this process? 1. The drift velocity of the conduction electrons in S 2. The de resistance of S 3. The number of conduction electrons in S Which of the following is correct? (a) Only 1 (b) 1 and 2 (c) 1, 2 and 3 (d) Only 3 |
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321 | For a common-emitter transistor, input current is ( 5 mu A, beta=100 . ) Circuit is operated at load resistance of ( 10 k Omega ). The voltage across collector emitter will be A. ( 5 v ) B. 10 ( v ) c. ( 12.5 mathrm{v} ) D. 7.5 ( v ) |
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322 | For the given circuit shown in figure, the potential of the battery is varied from ( 10 V ) to ( 16 V . ) If by zener diode breakdown voltage is ( 6 V ), find maximum current through zener diode. A. ( 1.5 mathrm{mA} ) в. 3.5 тА ( c .5 m A ) D. 6.5 m |
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323 | In a semiconductor, ( 2 / 3 r d ) of the total current is carried by electrons and remaining ( 1 / 3 r d ) by the holes. If at this temperature, the drift velocity of electrons is 3 times that of holes, the ratio of number density of electrons to that of holes is ( A cdot frac{3}{2} ) B. ( frac{2}{3} ) c. ( frac{5}{3} ) D. ( frac{3}{3} ) ( E cdot frac{1}{3} ) |
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324 | Which of the following circuit type is based upon time or clock pulse? A. Combinational circuit B. Sequential circuit c. Full adder D. None of these |
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325 | To convert a pure semiconductor into ( n ) type semi-conductor, what type of impurity is added to it? |
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326 | The thickness of the depletion region is of the order of of a micrometre. A. one-hundredth B. one-tenth c. one-thousandth D. None of these |
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327 | How many NAND gates are required to form an AND gate? A . 1 B. 2 ( c cdot 3 ) ( D ) |
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328 | The logic gate equivalent to the above combination of logic gates is A. OR B. NAND ( c cdot ) AND D. NOR |
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329 | For a transistor, the current amplification factor is ( 0.8 . ) The transistor is connected in common emitter configuration, the change in collector current when the base current changes by ( 6 m A ) is ( mathbf{A} cdot 6 m A ) в. ( 4.8 mathrm{mA} ) c. 24 m D. ( 8 m A ) |
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330 | For the circuit shown in the figure. The equivalent resistance between point ( mathbf{A} ) and ( mathrm{B} ) for the two cases ( (mathrm{i}) boldsymbol{V}_{boldsymbol{A}}>boldsymbol{V}_{boldsymbol{B}} ) (ii) ( V_{B}>V_{A} quad ) respectively is ( mathbf{Omega} ) and respectively ( left(D_{1} text { and } D_{2} ) are ideal right. diodes) ( A cdot 25, infty ) B. ( 50, infty ) ( mathrm{c} cdot infty, 25 ) D. 50.5 |
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331 | In the adjacent circuit, ( A ) and ( B ) represent two inputs and ( C ) represents the output. The circuit represents. A. NOR gate B. AND gate ( a quad ) ” ( quad ) ” gate ( D ) |
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332 | A potential barrier V volts exists across a P-N junction. The thickness of the depletion region is ‘d’. An electron with velocity ‘v’ approaches P-Njunction from N-side. The velocity of the electron crossing the junction is: A ( cdot sqrt{v^{2}+frac{2 V e}{m}} ) B. ( sqrt{v^{2}-frac{2 V e}{m}} ) ( c ) D. ( sqrt{frac{2 V e}{m}} ) |
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333 | toppr ( E ) Q Type your question. 0 ( A ) ( begin{array}{lll}A & B & Y \ 0 & 0 & 1end{array} ) 010 101 в. ( A B cdot Y ) ( 0 quad 0 quad 1 ) 0.11 101 c. ( A B Y ) 00 011 101 110 D. ( A B Y ) 00.1 011 |
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334 | The following configuration of gate is equivalent to A. NAND gate B. XOR gate c. or gate D. NOR gate |
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335 | What is forbidden energy gap(Eg) or band gap? A. Forbidden energy gap ( E_{g} ) is the difference of energy levels of conduction band and within conduction band B. Forbidden energy gap ( E_{g} ) is the difference of energy levels of conduction band and valence band. C. when there is no energy D. conduction band |
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336 | The creation of voltage or electric current in a material upon exposure to light is termed as A. photo-ionic effect B. thermi-ionic effect c. photo-voltaic effect D. None of these. |
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337 | In the bandgap between valence band and conduction band in a material is ( mathbf{5} . mathbf{0} e boldsymbol{V}, ) then the material is A. semiconductor B. good conductor c. superconductor D. insulator |
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338 | 4. In the following circuit, the equivalent resistance between A and B is τον 2ος -10 V -2V 8 Ω 12 Ω (b) 10Ω (c) 16 Ω (d) 20 Ω |
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339 | Sum of the two binary number ( (100010)_{2} ) and ( (11011)_{2} ) is ( mathbf{A} cdot(111101)_{2} ) B. ( (111111)_{2} ) ( mathbf{c} cdot(101111)_{2} ) D. ( (111001)_{2} ) |
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340 | What is the value of ( vec{A}+A ) in the boolean algebra? ( mathbf{A} cdot mathbf{0} ) B. ( c cdot A ) D. ( vec{A} ) |
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341 | Give band gap Eg value for conductor, insulator and semiconductor? A. Conductor ( <1 M e V ), insulation ( geq 6 e V ), semiconductor ( approx 8 e V ) B. Conductor ( <1 M e V ), insulation ( geq 6 e V ), semiconductor ( approx 1 e V ) C. Conductor ( <2 M e V ), insulation ( geq 6 e V ), semiconductor ( approx 1 e V ) D. Conductor< ( 1 mathrm{MeV} ), insulation ( geq 7 mathrm{eV} ), semiconductor ( approx 1 e V ) |
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342 | In a bridge rectifier, the number of diodes required is A . 1 B. 2 ( c .3 ) ( D ) |
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343 | In a half-wave rectifier circuit operating from ( 50 mathrm{Hz} ) mains frequency, the fundamental frequency in the ripple would be A. ( 10 mathrm{Hz} ) B. 25 Hz c. 50 нz D. 100 нz |
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344 | What is the conductivity of a semiconductor if electron density ( = ) ( 5 times 10^{12} / c m^{3} ) and hole density ( =8 times ) ( mathbf{1 0}^{13} / mathbf{c m}^{3}left(boldsymbol{mu}_{e}=mathbf{2 . 3 m}^{2} boldsymbol{V}^{-1} boldsymbol{s}^{-1}, boldsymbol{mu}_{boldsymbol{h}}=right. ) ( left.0.01 m^{2} V^{-1} s^{-1}right) ) ( mathbf{A} cdot 5.634 ) B. 1.968 c. 3.421 D. 8.964 |
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345 | The output of a 2 -input OR gate is zero only when its A. both inputs are 0 . B. either input is 1. c. both inputs are 1 D. either input is 0 |
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346 | 13. The shows two NAND gates followed by a NOR gate. The system is equivalent to the following logic gate (a) OR (c) NAND (b) AND (d) None of these |
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347 | Zener diode is a voltage regulation device. A . True B. False |
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348 | State whether True or False: A semiconductor at absolute zero become a insulator. A. True B. False |
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349 | A change of ( 8 m A ) in the emitter current brings a change of ( 7.9 m A ) in the collector current. The value of ( alpha ) is A. ( 80 / 79 ) B. ( 79 / 80 ) c. 79 D. 80 |
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350 | The energy gap in a semiconductor A. Increases with temperature B. Does not change with temperature C . Decreases with temperature D. Is zero |
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351 | The transfer characteristics of a transistor means a plot of A. input voltage versus input current B. output voltage versus output current c. input voltage versus output voltage D. input current versus output current |
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352 | Three variable Boolean expression ( boldsymbol{P Q}+boldsymbol{P Q R}+overline{boldsymbol{P}} boldsymbol{Q}+boldsymbol{P} overline{boldsymbol{Q}} boldsymbol{R} operatorname{can} mathrm{be} ) written as A. ( bar{Q}+bar{P} R ) в. ( bar{P}+bar{Q} R ) c. ( Q+P R ) D. ( Q+sqrt{P} R ) E . ( P+Q R ) |
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353 | Zener diode acts as a/an A . oscillator B. regulator c. rectifier D. fliter |
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354 | Suppose a pure Si crystal has ( 5 times 10^{28} ) atoms ( m^{-3} . ) it is doped by 1 ppm concentration of pentavalent As. Calculate the number of electrons and holes. Given that ( n_{1}=1.5 times 10^{16} m^{-3} ) |
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355 | Fill in the blanks. The traces of impurity added for doping are called |
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356 | Assertion A laser beam of ( 0.3 W ) can drill a hole through metal sheet, whereas light of ( 1000 W ) can not do so Reason Laser beam has very high frequency 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 |
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357 | The circuit shown below contains two diodes each with a forward resistance of ( 50 Omega ) and with infinite backward resistance. Find the current through ( 150 Omega ) resistor. A. zero B. ( 0.01 A ) c. ( 0.02 A ) D. 0.03 A |
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358 | In a N-P-N transistor about ( 10^{10} ) electrons enter the emitter in ( 2 mu s, ) when it is connected to a battery. Then ( boldsymbol{I}_{boldsymbol{E}}= ) ( boldsymbol{mu} boldsymbol{A} ) A . 200 в. 400 c. 800 D. 1600 |
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359 | Match the following a) p-type 1) Pure semiconductor semiconductor b) Intrinsic 2) Doped with impurity semiconductor c) Extrinsic 3) majority carriers are semiconductor ( quad ) electrons d) ( n ) -type 4) majority carriers are semiconductor holes ( A cdot a-3, b-2, c-4, d-1 ) B. ( a-1, b-2, c-4, d-3 ) C. ( a-4, b-1, c-2, d-3 ) D. ( a-2, b-1, c-4, d-3 ) |
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360 | In the middle of the depletion layer of a reverse-biased p-njunction, the A. electric field is zero B. potential is maximum c. electric field is maximum D. potential is zero |
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361 | What happens when a p-njunction is (a) forward biased (b) reverse biased? |
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362 | 4. In a common base amplifier, the phase difference between the input signal voltage and output voltage is (b) 0 (c) r (d) I (AIEEE 2005) |
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363 | Explain the working of a half wave diode rectifier. |
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364 | In ( n-p-n ) transistor circuit, the collector current is ( 5 mathrm{mA} ). If ( 98 % ) of electrons emitted reach the collector then the emitter current will be A . ( 5.1 mathrm{mA} ) B. 8.1 mA ( c cdot 6.5 mathrm{mA} ) D. ( 10 mathrm{mA} ) |
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365 | To get an output ( y=1 ) from the circuit shown, the inputs ( A, B ) and ( C ) must be respectively A. 0,1,0 B. 1,0,0 c. 1,0,1 D. 1,1 |
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366 | Which are good conductors? This question has multiple correct options A. silicon B. Silver c. copper D. glass |
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367 | What is true for an ideal transistor switch when turned OFF? This question has multiple correct options A. It has an infinite resistance B. It has low resistance c. It has maximum current flow D. It has zero current flow |
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368 | Diodes ( D-1 ) and ( D_{2} ) shown in circuit are silicon diodes.The voltage drop (V) across the diode ( D_{2} ) and the power dissipated (P) by this diode ( left(D_{2}right) ) are ( mathbf{A} cdot V_{D_{2}}=0.7 V ) and ( P_{D_{2}}=0 W ) B. ( V_{D_{2}}=5 V ) and ( P_{D_{2}}=0 W ) ( mathbf{C} cdot V_{D_{2}}=0.7 V ) and ( P_{D_{2}}=0.7 W ) D. ( V_{D_{2}}=5.0 V ) and ( P_{D_{2}}=5 W ) |
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369 | When NPN transistor is used as an amplifier? A. Electrons move from base to emitter B. Electrons move from emitter to collector c. Electrons moves from base to emitter D. Holes moves from base to emitter |
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370 | A semiconductor having electron and hole mobilities ( mu_{n} ) and ( mu_{p} ) respectively. if its intrinsic carrier density is ( n_{i}, ) then what will be the value of hole concentration ( P ) for which the conductivity will be minimum at a given temperature? A ( cdot n_{i} sqrt{frac{mu_{n}}{mu_{p}}} ) В ( cdot n_{h} sqrt{frac{mu_{n}}{mu_{p}}} ) ( mathbf{c} cdot n_{i} sqrt{frac{mu_{p}}{mu_{n}}} ) D. ( n_{h} sqrt{frac{mu_{p}}{mu_{n}}} ) |
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371 | Mention any four electronic gadgets. | 12 |

372 | Which logic gate corresponds to the truth table given below. ( begin{array}{lll}text { A } & text { в } & text { c } \ & & \ text { 0 } & text { o } & text { 1 } \ text { 0 } & text { 1 } & text { o } \ text { 1 } & text { 0 } & text { o } \ text { 1 } & text { 1 } & text { o }end{array} ) A. AND в. NOR ( c . ) or D. NAND |
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373 | 9. When on impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor (a) Increases (b) Decreases (c) Remains the same (d) Becomes zero . . |
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374 | What is the use of a Zener diode? | 12 |

375 | What is the optimum band gap energy for a material to be considered as a semiconductor? A. greater than ( 6 e V ) B. less than ( 6 e V ) c. ( 0 e V ) D. ( 0.5-3 e V ) |
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376 | From the following, reverse biased diode is ( A ) в. c. D. |
12 |

377 | The change in emitter current by ( 2.1 mathrm{mA} ) results in change of ( 2 mathrm{mA} ) in the collector current and a change of ( 0.05 V ) in the emitter base voltage. The input resistance is A . ( 5 K Omega ) в. зкл c. 1 К ( Omega ) D. 0.5к. |
12 |

378 | An ( L E D ) is constructed from a pn junction based on a certain semiconducting material whose energy gap is ( 1.9 e V . ) Then the wavelength of the emitted light is A ( .2 .9 times 10^{-9} mathrm{m} ) в. ( 1.6 times 10^{-8} mathrm{m} ) c. ( 6.5 times 10^{-7} m ) D. ( 9.1 times 10^{-5} m ) |
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379 | In half wave rectifier, a p-n diode with internal resistance ( 20 Omega ) is used. If the load resistance of ( 2 K Omega ) is used in the circuit, then the efficiency of this half wave rectifier is (in percentage) |
12 |

380 | The valency of impurity element for making p-type semiconductor is A . 5 B. 3 ( c cdot 4 ) ( D ) |
12 |

381 | The impurity atoms, with which pure silicon should be doped to make a ptype semiconductor, are those of This question has multiple correct options A. phosphorous B. boron C. antimony D. aluminium |
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382 | Which of the following is a correct statement about current carrying conductor? A. On increasing temperature drifts speed of free electron decreases B. On increasing temperature drift speed of free electron increases C. On increasing temperature, drift speed of free electron remains same. D. On increasing P.D. average kinetic energy of electron decreases ( Neglected heating effect of electric current) |
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383 | The reverse breakdown voltage of a Zener diode is ( 5.6 mathrm{V} ) in the given circuit The current ( I_{Z} ) through the Zener is ( mathbf{A} cdot 7 m A ) В. 17 тА ( c .10 m A ) D. ( 15 mathrm{mA} ) |
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384 | The drift current in a p-njunction is A. from the n-side to the p-side B. from the p-side to the n-side C. from the n-side to the p-side if the junction is forwardbiased and in the opposite direction if it is reverse biased D. from the p-side to the n-side if the junction is forwardbiased and in the opposite direction if it is reversebiased |
12 |

385 | 8. If the lattice constant of this semiconductor is decre then which of the following is correct? Conduction band gap T ITITIINIKE, band gap All B and E, in Valence band gap ZIMATIZITZZZZE, (a) All E., E., and E, decrease. (b) All E., E, and E, increase. (c) E, and E, increase, but E, decreases. (d) E, and E, decrease, but E, increases. (AIEEE 2006) decreas |
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386 | An oscillator is nothing but an amplifier with A. positive feedback B. large gain c. no feedback D. negative feedback |
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387 | Forbidden gap in a pure conductor is A. 0 eV B. 0.7 eV c. ( 1.1 mathrm{eV} ) D. 6 eV |
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388 | When the temperature changes, the operating point is shifted due to A. Change in ( I_{C B O} ) B. Change in ( V_{C C} ) C. Change in the values of circuit resistance D. None of the above |
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389 | Assertion In some solids, the valence band is completely filled while the next higher band separated by an energy gap of few electrons-volts is completely empty. Reason In insulators the energy band completely filled with electrons( the valence band) and above it is empty band (the conduction band) 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 |
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390 | The charge carriers in a p-type semiconductor are: A. electrons only B. holes only C. holes in larger numbers and electrons in smaller numbers D. holes and electrons in equal numbers |
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391 | Carbon, silicon and germanium have four valence electrons each. At room temperature the appropriate statement is A. The number of free electrons for conduction is significant only in Si and Ge but small in ( mathrm{C} ) B. The number of free conduction electrons is significant in C but small si and Ge. C. The number of free conduction electrons is negligibly small in all the three. D. The number of free conduction electrons is significant in all the three. |
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392 | In a photo-diode, A. photocurrent is proportional to incident light intensity B. photocurrent is inversely proportional to incident light intensity C. photocurrent is independent of the incident light intensity D. incident light intensity is proportional to the photocurrent |
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393 | The material selected for solar cell fabrication has This question has multiple correct options A. band gap (1.0 to 1.8 eV) B. high optical absorption ( left(10^{4} mathrm{cm}^{-1}right) ) c. electrical conductivity D. band gap (0.4 to 1. eV) |
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394 | Match the following: Left column lists the level of integration and right column lists the number of circuit components. |
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395 | The magnitude of the force between a pair of conductors, each of length 110 ( mathrm{cm}, ) carrying a current of ( 10 mathrm{A} ) and separated by a distance of ( 10 mathrm{cm} ) is A ( cdot 55 times 10^{-5} N ) B . ( 44 times 10^{-5} N ) c. ( 33 times 10^{-5} N ) D. ( 22 times 10^{-5} N ) |
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396 | If the collector current changes from ( 2 m A ) to ( 3 m A ) in a transistor when collector – emitter voltage is increased from ( 2 V ) to ( 10 V ), the output resistance is ( mathbf{A} cdot 1 K Omega ) B. ( 8 K Omega ) ( mathbf{c} cdot 8 m Omega ) D. ( 1 mathrm{m} Omega ) |
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397 | A Ge specimen is doped with Al. The concentration of acceptor atoms is ( sim ) ( 10^{21} ) atoms ( / m^{3} . ) Given that the intrinsic concentration of electron-hole pairs is ( 10^{19} / m^{3} . ) The concentration of electrons in the specimen is: ( mathbf{A} cdot 10^{17} / m^{3} ) B . ( 10^{15} / m^{3} ) c. ( 10^{4} / m^{3} ) D. ( 10^{2} / m^{3} ) |
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398 | The intrinsic semiconductor behaves as insulator at ( mathbf{A} cdot 0^{0} C ) B . ( 100^{circ} mathrm{C} ) c. ( 100 K ) D. ( 0 K ) |
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399 | When the p-njunction diode is reverse biased, the thickness of the depletion layer A . increases B. decreases c. becomes zero D. remain constant |
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400 | What is the state of an ideal diode in the region of nonconduction? A. Open circuit B. Short circuit c. undefined D. None of the above |
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401 | Why is a photodiode is used in reverse bias? A. Photocurrent flows only in reverse bias B. Thermally generated current is large in reverse bias as compared to the photocurrent C. Photocurrent is large in forward bias as compared to the forward bias current. D. Photocurrent is significant in reverse bias as compared to the reverse bias current. |
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402 | A light emitting diode (LED) has a voltage drop of ( 2 mathrm{V} ) across it and passes a current of 10 mA. When it operates with a ( 6 mathrm{V} ) battery through a limiting resistor ( R, ) the value of ( R ) is A . ( 200 Omega ) B. 400 ( Omega ) c. ( 40 k Omega ) D. 4 ( k Omega ) |
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403 | 84 10. Ge and Si diodes conduct at 0.3 V and 0.7 V, respectively. In the following figure if Ge diode connection are reversed, the valve of V. changes by (a) 0.2 V (b) 0.4 V (c) 0.6 V (d) 0.8 V 12 VI > 522 |
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404 | The truth table given is for which gate? ( begin{array}{ccc}mathbf{A} & mathbf{B} & mathbf{Y} \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0end{array} ) ( A cdot X O R ) B. OR C . AND D. NAND |
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405 | In class A amplifiers, current through load flows for A. full cycle of the signal B. half cycle of the signal c. ( frac{1}{4} ) cycle of the signal D. None of these |
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406 | Consider the circuit, the current through the Zener diode is ( A cdot 20 m A ) в. ( 10 mathrm{mA} ) ( c .15 mathrm{mA} ) D. ( 40 mathrm{mA} ) |
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407 | In a p-njunction diode, not connected to any circuit A. the potential is same everywhere. B. the p-type side is at a higher potential than the n-type side. C. there is an electric field at the junction directed from the n-type side to the p-type side. D. there is an electric field at the junction directed from the p-type side to the n-type side. |
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408 | Draw the circuit diagram of full-wave rectifier using two p-njunction diodes and explain its working. Show the input and output waveforms. |
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409 | Figure shown a DC voltage regulator circuit, with a Zener diode of breakdown voltage ( =6 V . ) If the unregulated input voltage varies between ( 10 V ) to ( 16 V ) then what is the maximum Zener current? A. ( 2.5 mathrm{mA} ) B. ( 3.5 mathrm{mA} ) c. ( 7.5 m A ) D. ( 1.5 mathrm{mA} ) |
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410 | Which logic gate is represented by the following combination of logic gates? A. OR в. NOR ( c cdot ) AND D. NAND |
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411 | Meeta’s father was driving her to the school. At the traffic signal she noticed that each traffic light was made of many tiny lights instead of a single bulb. When meeta asked this question to her father. he explained the reason for this. Answer the following based on above information: (i) What were the values displayed by meeta and her father? (ii) What answer did meeta’s father give? (iii) What are the tiny lights in traffic signals called and how do these operate? |
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412 | 5. A semiconductor device is connected in a serried circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops almost to zero. The device may be (a) Ap-type semiconductor (b) An n-type semiconductor (c) A p-n junction (d) An intrinsic semiconductor |
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413 | In forward bias, the depletion layer behaves like A . an insulator B. a conductor c. a semiconductor D. a capacitor |
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414 | 7. In the common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor (B) will be (a) 48 (b) 49 (c) 50 (d) 51 (AIEEE 2006) |
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415 | When a p-njunction is reverse biased, the current becomes almost constant at ( 25 mu A . ) When it is forward biased at ( 200 m e V, ) a current of ( 75 mu A ) is obtained Find the magnitude of diffusion current when the diode is (a) unbiased reverse-biased at ( 200 m V ) and forward-biased at ( 200 m V ) |
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416 | In a full wave rectifier circuit operating from ( 50 H z ) mains frequency, the fundamental frequency in the ripple would be ( mathbf{A} cdot 25 H z ) B. ( 50 mathrm{Hz} ) c. ( 70.7 H z ) D. ( 100 H z ) |
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417 | For a transistor amplifier in common emitter configuration for load impedance of ( 1 mathrm{k} Omegaleft(mathrm{h}_{f e}=50 text { and } mathrm{h}_{mathrm{o} e}=right. ) ( 25 mu A / V ), the current gain is: A. -5.2 B . -15.7 c. -24.8 D. -48.78 |
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418 | In the circuit diagram of zener diode as shown in figure, when the value of ( V_{0} ) is 8 volt, the current through zener diode s ( i_{1} ) and when ( V_{0} ) is 16 volt, the corresponding current is ( i_{2} . ) Find the value of ( left(i_{2}-i_{1}right) . ) (Zener breakdown voltage ( left.=V_{2}=6 Vright) ) A. zero B. ( 5.0 mathrm{mA} ) C ( .1 .5 mathrm{mA} ) ( mathbf{D} cdot 8 m A ) |
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419 | Zener diode is used as | 12 |

420 | Name two pentavalent impurities. | 12 |

421 | For one electron vacancy, A. no holes are created B. 1 hole is created C. 2 holes are created D. 4 holes are created |
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422 | What is rectification? With relevant circuit diagram and waveforms explain the working of a P-N junction diode as a full-wave rectifier. |
12 |

423 | The value of ( alpha ) of a transistor is ( 0.9 . ) The change in the collector current corresponding to a change of 4 m ( A ) in the base current in a common emitter arrangement is ( mathbf{A} .36 mathrm{mA} ) в. 72 тА ( c .18 m A ) D. 54 m |
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424 | Assertion In a common-emitter amplfier, the load resistance of the output circuit is 1000 times the load resistance of the input circuit. If ( boldsymbol{alpha}=mathbf{0 . 9 8}, ) then voltage gain is ( 49 times 10^{3} ) Reason ( boldsymbol{alpha}=frac{beta}{1-beta}( ) symbols have their usual meaning). 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 |
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425 | To make a p-njunction conducting A. The value of forward bias should be more than the barrier potenital B. The value of forward bias should be less than the barrier potential C. The value of revers bias should be more than the barrier potential D. The value of revers bias should be less than the barrier potential |
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426 | A pure germanium crystal at absolute zero is : A. an insulator B. a good conductor c. a semiconductor D. none of the above |
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427 | A pnjunction is a/an A. Bidirectional component B. Unidirectional Component C. Linear component D. None of these |
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428 | An intrinsic semiconductor is: A. undoped B. dopedd c. can be undoped or doped D. semi-doped |
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429 | The potential barrier of a silicon junction diode is ( 0.7 V . ) If the thickness of the depletion layer in it is ( 10^{-4} mathrm{cm} ) Then the intensity of electric field across the junction is A ( cdot 7 times 10^{3} V / m ) в. ( 7 times 10^{5} V / m ) C ( .7 times 10^{-5} V / m ) D. ( 7 times 10^{-4} V / m ) |
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430 | According to Moore’s Law: A. The memory capacity of a chip is constant. B. The memory capacity of a chip doubles every one and a half-years. C. The memory capacity of a chip increases by ten times every one and a half-years. D. The memory capacity of chip decreases with time. |
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431 | When PNjunction os forward biased the current in junction A. Increase B. decrease c. remains same D. None of these |
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432 | What is ‘depletion region’ in a semi conductor diode? | 12 |

433 | 1. A piece of copper and another of germanium are cooled to 77 K. The resistance of (a) each of them decreases. (b) each of them increases. (c) of Cu decreases and Ge increases. (d) of Cu increases and Ge decreases. (AIEEE 2004) |
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434 | The number 0 (zero) is required for A. transistor B. abacus c. computer D. calculator |
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435 | A full wave rectifier along with the output is shown in the given figure. The contributions from the diode ( left(D_{2}right) ) are ( A cdot C ) B. A, C ( c cdot B, D ) D. ( A, B, C, D ) |
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436 | A p-n photodiode is manufactured from a semiconductor with gap of ( 3.1 mathrm{eV} ) Which of the following wavelengths can be detected by it? ( A cdot 4000 hat{A} ) в. 3900 , ( c cdot 4200 hat{A} ) D. Both (1) & (2) |
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437 | The drift velocity of electrons in a conductor is : A. Very small B. Very large c. Equal to the velocity of the tight D. Varies with the conductor |
12 |

438 | Write the names of two important processes which occur on formation of p-njunction. Define the ‘depletion region’ and ‘potential barrier’ in it. |
12 |

439 | Given above are four logic gate symbols. Those for OR, NOR and NAND are respectively ( A cdot a, d, c ) B. ( d, a, b ) ( c cdot a, c, d ) ( D cdot d, b, a ) |
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440 | In intrinsic semiconductor at room temperature number of electrons and holes are: A. Equal B. zero c. Unequal D. Infinite |
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441 | State whether true or false: A bulb is used in place of LED to detect weak currents. A. True B. False |
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442 | Which of the following is/are correct about the direction of holes/electron? This question has multiple correct options A. Holes are moving along the direction of electric field. B. Electrons are moving along the direction of electric field. C. Electrons are moving against the direction of electric field. D. None of the above |
12 |

443 | To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behave like: A. a conductor B. a p-type semi-conductor c. an n-type semi-conductor D. an insulator |
12 |

444 | When plate voltage in diode valve is increased from ( 100 mathrm{V} ) to ( 150 mathrm{V} ). Then, plate increases from ( 7.5 mathrm{mA} ) to ( 12 mathrm{mA} ), then dynamic plate resistance will be ( mathbf{A} cdot 10 k Omega ) B. ( 11 k Omega ) ( mathbf{c} cdot 15 k Omega ) D. ( 11.1 k . Omega ) |
12 |

445 | What is rectification? Explain the working of bridge rectifier. Draw the input and output signals. | 12 |

446 | The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature A. decreases exponentially with increasing band gap B. increases exponentially with increasing band gap c. decreases with increasing temperature D. is independent of the temperature and the band gap |
12 |

447 | When ( n-p-n ) transistor is used as an amplifier: A. electrons move from base to collector B. holes moves from emitter to base C. holes move from collector to base D. holes move from base to emitter |
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448 | Carbon, Silicon and Germanium atoms have limn valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by ( left(boldsymbol{E}_{boldsymbol{g}}right)_{boldsymbol{c}},left(boldsymbol{E}_{boldsymbol{g}}right)_{boldsymbol{s i}} ) and ( left(boldsymbol{E}_{boldsymbol{g}}right)_{boldsymbol{G} boldsymbol{e}} ) respectively. Which one of the following relationship is true in their case? A ( cdotleft(E_{g}right)_{C}>left(E_{g}right)_{s i} ) B. ( left(E_{g}right)_{C}<left(E_{g}right)_{s i} ) ( mathbf{c} cdotleft(E_{g}right)_{C}=left(E_{g}right)_{s i} ) D cdot ( left(E_{g}right)_{C}<left(E_{g}right)_{G e} ) |
12 |

449 | Explain the use of P-N junction diode as full wave rectifier on the basis of the following points. (i) Labelled circuit diagram (ii) Working method (iii) Graph between input and output potential with the variation of time. |
12 |

450 | State the properties and uses of a Junction Diode. | 12 |

451 | In the middle of the depletion layer of a reverse biased ( p-n ) junction, the A. Potential is zero B. Potential is maximum c. Electric field is maximum D. Electric field is zero |
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452 | The mobility of free electrons is greater than that of free holes because A. they carry negative charge B. they are light C. their mutual collisions are less D. they require low energy to continue their motion |
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453 | 000 following |
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454 | A transistor is used in the common emitter mode as an amplifier. Then This question has multiple correct options A. the base-emitter junction is forward-biased. B. the base-emitter junction is reverse-biased. C. the input signal is connected in series with the voltage applied to bias the base-emitter junction. D. the input signal is connected in series with the voltage applied to bias the base-collector junction In p-type semiconductor ( n_{h}>n_{e} ) |
12 |

455 | 22 out 5. In the following common emitter configuration an NPN transistor with current gain B = 100 is used. The output voltage of the amplifier will be (a) 10 mV (b) 0.1 V (c) 1.0 V (d) 10 V |
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456 | The conductivity of a semi conductor is: This question has multiple correct options A. Greater than the conductivity of metals. B. Less than the conductivity of metals. C. Equal to the conductivity of metals. D. Intermediate between the conductivity of metals and insulators. |
12 |

457 | State whether given statement is True or False A germanium crystal is doped with boron impurity A. True B. False |
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458 | What are the functions of three regions of a transistor? |
12 |

459 | 76. An input voltage V; of 0.20 V is applied to an operational amplifier connected as shown in the diagram. What is the output voltage Vo? +8.0 V 8.0 v 10 ks 2.0 k81 V = 0.20 V (a) 0.20 V (c) 0.80 V (b) 1.2 V (d) 8.0 V |
12 |

460 | What is the output Y in the following circuit when all the three inputs ( A, B, C ) are first 0 and then ( 1 ? ) A . 1,1 в. 0,1 ( c .0,0 ) D. 1,0 |
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461 | The ( V ) -I characteristic of a diode is shown in the figure. The ratio of forward to reverse bias resistance is : 4.10 ( 3 cdot 10^{-6} ) ( c .1 ) 0.10 |
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462 | 6. If the ratio of concentration of electrons to that of holes in a semiconductor is 7/5 and the ratio of currents is 7/4, what is the ratio of their drift velocities? (b) 5 noont (c) 4 (d) (AIEEE 2006) |
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463 | Insulators are materials having an electrical conductivity equal to: A. Between ( 10^{-8} mathrm{S} / mathrm{cm} ) to ( 10^{3} mathrm{S} / mathrm{cm} ) B. ( 10^{3} mathrm{S} / mathrm{cm} ) |
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464 | In the given circuit, the voltage across the voltage across the load is maintained at ( 12 mathrm{V} ). The current in the zener diode varies from 0-50 mA. What is the maximum watage of the diode? ( A cdot 12 W ) B. 6 w c. ( 0.6 w ) D. ( 1.2 mathrm{w} ) |
12 |

465 | We are familiar with the semiconductors Silicon and Germanium. a) Draw the energy bands of a ( n ) -type semiconductor. b) The following figure represents a |
12 |

466 | In the Boolean algebra, the following one is wrong A . ( 1.0=0 ) B. ( 0.1=0 ) c. ( 1.1=0 ) D. ( 1.1=1 ) |
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467 | The input resistance of a common emitter transistor amplifier, if the output resistance is ( 500 mathrm{k} Omega ), the current gain ( alpha=0.98 ) and the power ( operatorname{gain} ) is ( 6.0625 times 10^{6}, ) is ( mathbf{A} cdot 198 Omega ) в. 300Omega c. ( 100 Omega ) D. ( 400 Omega ) |
12 |

468 | Assertion An ( n- ) type semiconductor has a large number of electrons but still it is electrically neutral Reason An ( n- ) type semicondutor is obtained by doping an intrinsic semiconductor with a pentavalent impurity. 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 |
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469 | (i) Define rectification. (ii) Draw a circuit diagram of a full- wave rectifier. (iii) Semi-conductor related to given energy band diagram is: n-type semi-conductor, p-type semiconductor or intrinsic semi-conductor. |
12 |

470 | In a semiconductor, acceptor impurity is : A. Antimony B. Indium c. Phosphorous D. Arsenic |
12 |

471 | A potential barrier of ( 0.5 mathrm{V} ) exists across a p-njunction (i) If the depletion region is ( 5 times 10^{-7} ) m wide. What is the average intensity of the eectric field in this region? (ii) An electron with speed ( 5 times ) ( 10^{5} mathrm{m} / mathrm{s} ) approaches the ( mathrm{p} ) -n junction from the n-side with what speed will it enter the p-side? |
12 |

472 | In the depletion layer of p-njunction diode, these are presents. A. Only holes B. Only electrons c. Electrons and holes both D. Neither electron nor hole |
12 |

473 | The rating of a zener diode is ( 1 W, 15 V ) Find the zener maximum current. ( mathbf{A} cdot 66.7 A ) в. ( 1 A ) ( c .15 A ) D. ( 66.7 m A ) |
12 |

474 | Consider a two-input AND gate of figure below. Out of the four entries for the Truth Table given here, the correct ones are ( -1-1 ) begin{tabular}{|c|c|c|c|} hline multirow{2}{*} {1} & A & B & C \ cline { 2 – 5 } & 0 & 1 & 0 \ cline { 2 – 4 } & 1 & 0 & 0 \ cline { 2 – 4 } 3 & 1 & 1 & 1 \ hline multirow{2}{*} {4} & 0 & 0 & 1 \ hline end{tabular} ( mathbf{A} cdot ) Al B. 1 and 2 only C. 1,2 and 3 only D. 1,3 and 4 only |
12 |

475 | The element that can be used as acceptor impurity to dope silion is : A. Antimony B. Arsenic c. Boron D. Phosphorous |
12 |

476 | 18. The current through an ideal P-N junction shown in the following circuit diagram will be re 10022 las 7 1 V 2 V 7 cm (a) zero A ED (c) 10 mAh (b) 1 mA 100 (d) 30 mA |
12 |

477 | A p-njunction diode cannot be used A. as a rectifier. B. for converting light energy to electric energy. C . for getting light radiation. D. for increasing the amplitude of an AC signal. |
12 |

478 | A NOR gate and a NAND gate are connected as shown in the figure. Two different sets of inputs are given to this setup. In the first case, the inputs to the gates are ( boldsymbol{A}=mathbf{0}, boldsymbol{B}=mathbf{0}, boldsymbol{C}=mathbf{0} . ) In the second case, the inputs are ( boldsymbol{A}=mathbf{1}, boldsymbol{B}= ) ( 0, C=1 . ) The output ( D ) in the first case and second case respectively are: A. 0 and 0 B. 0 and 1 c. 1 and 0 D. 1 and 1 |
12 |

479 | In n type semiconductor, electrons are majority charge carriers but it does not show any negative charge. The reason is A. Electrons are stationary B. Electrons neutralize with holes c. Mobility of electrons is extremely small D. Atom is electrically neutral |
12 |

480 | If ( A=1 ) and ( B=0, ) than ( A . A+B ) in the Boolean expression is equal to A. ( B ) в. c. ( A . B ) D. B.B |
12 |

481 | The peak voltage in the output of a halfwave diode rectifier fed with a sinusoidal signal without filter is ( 10 mathrm{V} ) The d.c. component of the output voltage is A. ( 10 / sqrt{2} V ) в. ( 10 / pi V ) ( c cdot 10 v ) D. ( 20 / pi V ) |
12 |

482 | begin{tabular}{|c|c|} hline 0 \ ( -5 mathrm{V} ) \ hline end{tabular} ( 5 mathrm{V} ) 0 0 ( -10 mathrm{V} ) ( 10 mathrm{V} ) ( log _{10} 10 ) |
12 |

483 | NAND and NOR gates are called universal gates primarily because they A. are available universally B. can be combined to produce OR, AND and NOT gates c. are widely used in Integrated circuit packages D. are easiest to manufacture |
12 |

484 | 49. Which of the following gates corresponds to the truth table given below? Α. IB х 0 1 0 1 011 001 (a) XOR (c) NAND (b) OR (d) NOR JAN |
12 |

485 | A hole is A. a positively charged electron. B. an electron in the valence band. C. an unfilled covalent bond. D. an excess electron in covalent bond. |
12 |

486 | A PN-junction has a thickness of the order of : A ( .1 g m ) B. ( 1 mathrm{mm} ) ( mathrm{c} cdot 1 mu mathrm{m} ) D. ( 1 p ) m |
12 |

487 | Derive the expression for the voltage gain of a transistor amplifier in ( mathrm{CE} ) configuration terms of the load resistance ( boldsymbol{R}_{boldsymbol{L}} ). current gain ( boldsymbol{beta}_{boldsymbol{a}} ) and input resistance. Explain why input and output voltages are in opposite phase. |
12 |

488 | The process of introducing impurities in small quantities into an intrinsic semiconductor is called Doping. A. True B. False |
12 |

489 | The junction diode shown in figure is ideal. The current in the circuit is A . ( 50 A ) в. ( 30 A ) ( c .20 m A ) D. 30 ( m A ) |
12 |

490 | Among the following, one statement is not correct when a junction diode is in forward bias A. the width of depletion region decreases. B. free electron on n- side will move towards the junction c. holes on p-side move towards the junction D. electrons on n-side and holes on p-side will move away from junction. |
12 |

491 | The energy gap in glass at room temperature is: A. greater than that in a semiconductor B. less than that in a good conductor C . greater than that in a good conductor D. both (A) and (C) are true |
12 |

492 | Which one of the following statements is not correct in case of a semiconductor? A. Temperature coefficient of resistance is negative B. Doping increases conductivity c. At absolute zero temperature, it behaves like an conductor D. Resistivity is in between that of a conductor and insulator |
12 |

493 | A Zener diode is connected to a battery and a load as shown. The currents ( boldsymbol{I}, boldsymbol{I}_{boldsymbol{Z}} ) and ( I_{L} ) are respectively ( mathbf{A} cdot 12.5 m A, 5 m A, 7.5 m A ) B. ( 15 mathrm{mA}, 7.5 mathrm{mA}, 7.5 mathrm{mA} ) c. ( 15 mathrm{mA}, 7.5 mathrm{mA}, 5 mathrm{mA} ) D. ( 12.5 mathrm{mA}, 7.5 mathrm{mA}, 5 mathrm{mA} ) |
12 |

494 | The thickness of depletion region is of the order of A. ( 0.1 mu m ) в. ( 1 mu ) т c. ( 0.1 m m ) D. ( 1 mathrm{mm} ) |
12 |

495 | Which logic gate is represented by the following combination of logic gates: A. OR B. NAND ( c . ) AND D. NOR |
12 |

496 | For transistor action which of the following statements is correct? This question has multiple correct options A. Base, emitter and collector regions should have similar size and doping concentration. B. The base region must be very thin and lightly doped. C. The emitter junction is forward biased and collector junction is reverse biased. D. Both emitter junction and collection junction are forward biased. |
12 |

497 | A potential barrier of ( 0.5 mathrm{V} ) exists across a p-njjunction. If the width of depletion layer is ( 10^{-6} m ), then intensity of electric field in this region will be A ( .1 times 10^{6} V / m ) в. ( 5 times 10^{5} mathrm{V} / mathrm{m} ) c. ( 4 times 10^{4} V / m ) D. ( 2 times 10^{6} mathrm{V} / mathrm{m} ) |
12 |

498 | Potential difference across depletion regions A. creates due to build up of space charge B. limits further diffusion of electrons and holes across the depletion plane c. should not be zero D. both ( A ) and ( B ) |
12 |

499 | The majority carriers in a p-type semiconductor are A. Electrons B. Holes c. Both A and B D. Impurities |
12 |

500 | The impurity atoms with which pure silicon may be doped to make it a ( mathrm{p} ) type semiconductor are those of Imore than one option may he correct] This question has multiple correct options A. phosphorus B. boron C. antimony D. aluminium |
12 |

501 | Draw separate energy band diagrams for conductors, semi-conductors and insulators and label each of them. | 12 |

502 | The part of a transistor which is heavily dopped to produce a large number of majority carriers is: A. Base B. Emitter c. collector D. None of these |
12 |

503 | In a common base transistor circuit, the current gain is ( 0.98 . ) On changing the emitter current by ( 5.00 mathrm{mS} ), the change in collector current is? A. ( 0.196 mathrm{mA} ) B. ( 2.45 mathrm{mA} ) c. ( 4.9 mathrm{mA} ) D. ( 5.1 mathrm{m} ) A |
12 |

504 | An n-type and p-type silicon can be obtained by doping pure silicon with: A. arsenic and phosphorous B. indium and aluminium c. phosphorous and indiumm D. aluminium and boron |
12 |

505 | The n-side of the depletion layer of a p-n junction. A. Always has same width as of the p-side B. Has no bound charges c. Is negatively charged D. Is positively chargedd |
12 |

506 | The figure shows the input waveforms ( A ) and B for ‘AND’ gate. Draw the output waveform and write the |
12 |

507 | p-type crystal of p-njunction diode is connected to a positive terminal of battery and n-type crystal connected to negative terminal of battery. Then A. diode is forward biased. B. diode is reversed biased. C. potential barrier in depletion layer increases. D. potential barrier in depletion layer remains unchanged. |
12 |

508 | LED glows even when a electric current passes through it. Fill in the blank. ( A ). weak c. can’t predicted D. none of the above |
12 |

509 | The relationship between band gap energy and temperature can be described by A. supersymmetric quantum mechanics B. hyperuniformity. c. phonons theory. D. Varshni’s empirical expression |
12 |

510 | Pure ( S e ) at ( 300 K ) has equal electron ( left(n_{e}right) ) and hole ( left(n_{h}right) ) concentration of ( 1.5 times ) ( 10^{6} m^{-3} . ) Doping by indium increases ( boldsymbol{n}_{boldsymbol{h}}=mathbf{4 . 5} times mathbf{1 0}^{mathbf{2 2}} boldsymbol{m}^{-mathbf{3}} . ) Calculate the doped silicon. |
12 |

511 | A semiconductor is doped with a donor İmpurity: This question has multiple correct options A. the hole concentration increases B. the hole concentration decreases C. the electron concentration increases D. the electron concentration decreases |
12 |

512 | 3. In the following circuit I, and I are respectively 2 k92 10 V 14 KOS 12 03 (a) 0,0 (c) 5 mA, 0 (b) 5 mA, 5 mA (d) 0,5 mA |
12 |

513 | Write the two examples of acceptor impurities |
12 |

514 | In forward bias of p-njunction, the potential barrier A. increases B. decreases c. remains unchanged D. becomes zero |
12 |

515 | A laser beam passes through the air into a piece of plexiglass. Find out the possible change in property of the laser beam A. The velocity decreases B. The wavelength increases c. The frequency decreases D. The period decreases E. None of the above is true |
12 |

516 | Which of the following cannot be used in electronic devices? A. Aluminium gallium arsenide B. Indium gallium arsenide c. Gallium arsenide D. Quasicrystals. |
12 |

517 | A p-n photodiode is made of a material with a band gap of ( 2.0 e V . ) The minimum frequency of the radiation that can be absorbed by the material is nearly: ( mathbf{A} cdot 10 times 10^{14} mathrm{Hz} ) B . ( 5 times 10^{14} mathrm{Hz} ) c. ( 1 times 10^{14} H z ) D. ( 20 times 10^{14} mathrm{Hz} ) |
12 |

518 | When the maximum clock rate is quoted for a logic family, it applies to a A. Shift register B. Flip-flop c. counter D. single logic gate |
12 |

519 | If the photo-diode is biased with a voltage larger than the specified maximum reverse bias, then: A. the device may suffer breakdown B. the device’s efficiency will increase c. the device will become forward biased D. none of the above |
12 |

520 | Which of the following is/are correct regarding the working principle of LED? This question has multiple correct options A. When an electron makes a transition to the valance band to fill up a hole in a p-njunction, it emits energy in the form of photon B. The energy of this photon is equal to the energy gap between conducction band and valance band energy levels C. Energy of a photon is the product of frequency of electromagnetic radiation (f) and Planck constant (h) D. Both A and B |
12 |

521 | Using Nand twice of two inputs ( A & B ) will give: A. AND в. ов c. It can not be done D. None of these |
12 |

522 | uut 010 -11.-11.5=0.4 V 11. In the circuit shown in figure, the maximum output voltage Vois 10 v H- DD N 2k12 T/2 0 + Vo 2k 2 2 ks (b) 5 V (a) O V (c) 10 V |
12 |

523 | ILLUSTRATION 31.7 Write the truth table for circuit given in figure consisting of NOR gate and identify the logic operation (OR, AND, NOT) which this circuit is performing. BO |
12 |

524 | Minority carriers in a p-type semiconductor are ( mathbf{A} cdot ) free electrons B. holes C. neither holes nor free electron D. both holes and free electrons |
12 |

525 | Assertion Most amplifiers use common emitter circuit configuration Reason Its input resistance is comparatively higher 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 |

526 | In a semi-conducting material the mobilities of electrons and holes are ( mu_{e} ) and ( mu_{h} ) respectively. Which of the following is true? A ( cdot mu_{e}>mu_{h} ) в. ( mu_{e}0 ) |
12 |

527 | A red LED emits light at0.1 watt uniformly around it. The amplitude of the electric field of the light at a distance of ( 1 mathrm{m} ) from the diode is : ( mathbf{A} cdot 6 V / m ) в. ( 2.45 V / m ) c. ( 5.48 V / m ) D. ( 1.73 V / m ) |
12 |

528 | What are the advantages of Integrated Circuits (IC) | 12 |

529 | 24. A triode has a plate resistance of 10 k 2 and amplification factor 24. If the input signal voltage is 0.4 V (r.m.s.), and the load resistance is 10 k2, then, the output voltage (r.m.s.) is (a) 4.8 V (b) 9.6 V (c) 12.0 V (d) none of these |
12 |

530 | Zener-diode is used in. A. Amplification B. Rectification C. Oscillator in producing oscillations D. Volatge regulation |
12 |

531 | What is the resistivity of a pure semiconductor at absolute zero? A. Zero B. Infinity C. Same as that of conductors at room temperature D. Same as that of insulators at room temperature |
12 |

532 | A) Draw a typical illuminated ( boldsymbol{P}-boldsymbol{n} ) junction solar cell. B) LED convert ( _{text {一一一一一一 }} ) energy to light. |
12 |

533 | In a semiconductor, which of the following statement is correct? A. At ( 0 K ), Si is a super conductor. B. In a p-type semiconductor the acceptor level lies near the conduction band. C. Each donor atom contributes one hole. D. ( p-n ) junction is electrically neutral |
12 |

534 | Which gates are called universal gates? | 12 |

535 | In LED visible light is produced by A. Gallium phosphide B. Gallium arsenide c. Germanium phosphide D. silicon phosphide |
12 |

536 | Construct the circuit symbol of Zener diode |
12 |

537 | In an intrinsic semiconductor, the Fermi energy level is A. nearer to valence band than conduction band. B. equidistant from conduction band and valence band. C. nearer to conduction band than valence band. D. bisecting the conduction band |
12 |

538 | 9. A diode is connected to 220 V (rms) ac in series with a capacitor 220 V as shown in figure. The voltage across the capacitor is (a) 220 V (b) 110 V (c) 311.1 V (2) 220 V |
12 |

539 | The lead marked with the arrow is the A . collector B. base c. emitter D. cor |
12 |

540 | State True or False : The n-type collector moves very little while p-type moves appreciably. A. True B. False |
12 |

541 | In a Zener regulated power supply of a Zener diode with ( V_{2}=6 V ) is used for regulation. The load current is to be ( 4 m A ) and the unregulated input is ( 10 V ) The value of series resistor ( boldsymbol{R}_{boldsymbol{S}} ) is (Assume ( left.boldsymbol{I}_{z}=mathbf{5} boldsymbol{I}_{L}right) ) A. less than ( 5 Omega ) B. Infinite c. greater than ( 100 Omega ) D. zero |
12 |

542 | When a p-njunction diode is connected in forward bias its barrier potential A. decreases and less current flows in the circuit B. decreases and more current flows in the circuit C. increases and more current flows in the circuit D. decreases and no current flows in the circuit |
12 |

543 | Among the following, the wrong statement in the case of semiconductor is: A. Resistivity is in between that of a conductor and insulator B. Temperature coefficient of resistance is negative c. Doping increases conductivity. D. At absolute zero temperature, it behaves like a conductor |
12 |

544 | The addition of pentavalent impurities of the semiconductor. A. brings no change to the conductivity B. decreases the conductivity c. increases the conductivity D. reduces the formation of free electrons |
12 |

545 | The Wavelength of a LASER beam can be used as a standard of A. time B. temperature c. angle D. length |
12 |

546 | When a diode is heavily doped the A. Zener voltage will be low B. Avalanche voltage will be high C. Depletion region will be thin D. Leakage current will be low |
12 |

547 | The diode cannot be A. the simplest of semiconductor devices. B. having characteristics that closely match those of a simple switch C. is a multi terminal device D. none of the above |
12 |

548 | For the circuit show below, the current through the zener diode is : ( A cdot 5 ) m B. Zero c. ( 14 mathrm{mA} ) ( 0.9 mathrm{m} ) |
12 |

549 | Amplifier may be A. multi stage B. single stage ( c . ) both (a) & (b) D. None of these |
12 |

550 | p-njunction diode can be used as A. amplifer B. detector c. oscillator D. capacitor |
12 |

551 | Which of the following is not a rectifier circuit? 4 3 ( c ) . none of thes |
12 |

552 | Solar cells are made of : A. silicon B. germaniuminmmmmm c. silver D. aluminium |
12 |

553 | a germanium crystal with arsenic ( (Z= ) 33). A second semi-conductor Y is made by doping germanium with indium ( Z=49 ). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct- A. ( x ) is ( p ) -type, ( Y ) is ( n ) -type and the junction is forward biased B. ( x ) is ( n ) -type, ( Y ) is ( p ) -type and the junction is forward biased c. ( x ) is ( p ) -type, ( Y ) is ( n ) -type and the junction is reverse biased D. ( x ) is ( n ) -type, ( Y ) is ( p ) -type and the junction is reverse biased |
12 |

554 | In figure the input is across the terminals ( A ) and ( C ) and the output is across ( mathrm{B} ) and ( mathrm{D} ). Then the output is A . zero B. same as input C. half wave rectifier D. full wave rectifier |
12 |

555 | If ‘p’ region of a semi conductor is connected to negative and ‘n’ region to positive pole, it is said to be A. directed biased B. unbiased c. forward biased D. reverse biased |
12 |

556 | The input signal given to a a CE amplifier having a voltage gain of 150 is ( V_{i}=2 cos left(15 t+frac{pi}{3}right) . ) The corresponding output signal will be A ( cdot 300 cos left(15 t+frac{4 pi}{3}right) ) B. ( 300 cos left(15 t+frac{pi}{3}right) ) c. ( 75 cos left(15 t+frac{2 pi}{3}right) ) D. ( 2 cos left(15 t+frac{5 pi}{6}right) ) |
12 |

557 | What is meant by feedback? Derive an expression for voltage gain of an amplifier with negative feedback. | 12 |

558 | In a junction transistor the emitter, base and collector are made of A. extrinsic semiconductors B. intrinsic semiconductors c. both A and B D. metal. |
12 |

559 | Which of the following is a property of a Light Emitting Diode (LED)? A. Low Threshold Voltage and High Reverse Breakdown Voltage B. High Threshold Voltage and High Reverse Breakdown voltage c. High Threshold Voltage and Low Reverse Breakdown Voltage D. Low Threshold Voltage and Low Reverse Breakdown voltage |
12 |

560 | A pulse waveform has a high time of 8 ms and a pulse width of 32 ms. The duty cycle is A . 25% B. 50% c. 1% D. 100% |
12 |

561 | Which of these is the best description of a Zener diode? A. It is a constant voltage device. B. It operates in the reverse region c. It is a constant current device D. It works in forward region |
12 |

562 | For a common emitter circuit amplifier, the load resistance of the output circuit is 500 times the resistance of the input. circuit. If ( alpha=0.98, ) then, current gain is A . 0.98 B. 50 c. 98 D. 49 |
12 |

563 | Which of the following is not a type of an IC? A. Analog IC B. Digital IC c. Mixed IC D. compound IC |
12 |

564 | Materials which allow only larger currents to flow through them are A. Insulators B. Semi-conductors c. conductors D. Alloys |
12 |

565 | The probability of electrons to be found in the condition band of an intrinsic semiconductor 6 at a finite temperature. A. Increases exponentially with increasing band gap B. Decreases exponentially with increasing band gap c. Decreases with increasing temperature D. Is independent of the temperature and the band gar |
12 |

566 | A diode made of silicon has a barrier potential of ( 0.7 ~ V ) and a current of ( 20 m A ) passes through the diode when a battery of emf ( 3 V ) and a resistor is connected to it. The power dissipated across the resistor and diode are A. ( 0.046 mathrm{W}, 0.014 mathrm{W} ) в. ( 4.6 mathrm{W}, 0.14 mathrm{W} ) c. ( 0.46 W, 0.14 W ) D. ( 46 W, 14 W ) |
12 |

567 | ( ln mu_{e} ) and ( mu_{h} ) are electron and hole mobility. E be the applied electric field, the current density ( J ) for intristic semiconductor is equal to ( mathbf{A} cdot n_{i} eleft(mu_{e}+mu_{h}right) E ) B ( cdot n_{i} eleft(mu_{e}-mu_{h}right) E ) c. ( frac{n_{i} eleft(mu_{e}+mu_{h}right)}{E} ) D. ( frac{E}{n_{i} eleft(mu_{e}+mu_{n}right)} ) |
12 |

568 | The level formed due to impurity atom,in the forbidden energy gap,very near to the valence band in a p-type semiconductor is called A. acceptor level B. donor level c. conduction level D. forbidden level |
12 |

569 | One serious drawback of semi- conductor devices is A. they do not last for long time. B. they are costly. c. they cannot be used with high voltage. D. they pollute the environment |
12 |

570 | When transistors are used in digital circuits they usually operate in A. active region B. breakdown region c. linear region D. saturation and cutoff regions |
12 |

571 | The energy gap in case of which of the following is less than ( 3 e V ? ) A. Aluminium B. Iron c. Germanium D. copper |
12 |

572 | Tu Oy LUL 16. Which one is in forward bias? (d) None of these |
12 |

573 | The value of ( A . bar{A} ) in Boolean algebra is ( mathbf{A} cdot mathbf{0} ) B. ( c . A ) D. ( bar{A} ) |
12 |

574 | Pure ( S i ) at ( 500 K ) has equal number of electron ( left(boldsymbol{n}_{e}right) ) and hole ( left(boldsymbol{n}_{boldsymbol{h}}right) ) concentration of ( 1.5 times 10^{16} m^{-3} ) Doping by indium increases ( n_{h} ) to ( 4.5 times ) ( 10^{22} m^{-3} . ) The doped semiconductor is of A ( cdot n ) -type with electron concentration ( n_{e}=5 times 10^{22} mathrm{m}^{-3} ) B . p-type with electron concentration ( n_{e}=2.5 times 10^{10} mathrm{m}^{-3} ) C . ( n ) -type with electron concentration ( n_{e}=2.5 times 10^{23} mathrm{m}^{-3} ) D. ( p ) -type having electron concentrations ( n_{e}=5 times ) ( 10^{9} m^{-3} ) |
12 |

575 | The output of NOT gate when its input is ( mathbf{0} ) ( A ). is 1 B. is 0 c. can be 0 or 1 D. is 0 and 1 |
12 |

576 | The depletion region in a semiconductor diode is formed at the A. thermonic emitter B. junction c. diode D. forbidden zone |
12 |

577 | Solar cells are made up of: A. conductors B. insulators c. semiconductors D. superconductors |
12 |

578 | A Zener diode A. has a high forward voltage rating B. has a sharp breakdown at low reverse voltage C. has a negative resistance D. none of the above |
12 |

579 | The output of an OR gate is connected to both the inputs of a NAND gate. The combination will serve as: A. AND gate B. NOT gate c. NAND gate D. NOR gate |
12 |

580 | For transistor action, state which statements are true: (1) Base, emitter and collector regions should have similar size and doping concentrations. (2) The base region must be very thin and lightly doped. (3) The emitter-base junction is forward biased and base-collector junction is reverse biased (4) Both the emitter-base junction as well as the base-collectorjunction are forward biased ( A cdot(4) ) and (1) B. (1) and (2) c. (2) and (3) ( D cdot(3) ) and (4) |
12 |

581 | What is the reason to operate the photodiodes in reverse bias? A. fractional change due to the photo-effects on the majority carrier dominated forward bias current is more easily measurable than the fractional change in the reverse bias current. B. reverse bias is more efficient than forward bias. C. fractional change due to the photo-effects on the minority carrier dominated reverse bias current is more easily measurable than the fractional change in the forward bias current. D. reverse bias configuration result in larger amount of current ( (operatorname{in} mu A) ) |
12 |

582 | The light emitting diode (LED) is A. a heavily doped p-n junction with no external bias B. a heavily doped p-n junction with reverse bias C. a heavily doped p-njunction with forward bias D. a lightly doped p-n junction with no external bias E . a lightly doped p-n junction with reverse bias |
12 |

583 | 63. The circuit diagram (see the figure) shows a login combination with the states outputs X, Y and Z given for inputs P, Q, R and S at state 1 (i.e., high). When inputs P and R change to state 0, (i.e., low) with inputs Q and still at 1, the condition of output X, Y and Z changes to P(1) ANDH 9X(1) Q(1) Y(1) NOR Z(0) R(1) – NOR NOR NOT NOT Horn S(1) I (a) I (6) I (6) I d o x 1 1 0 1 0 IY Io Ti I 10 1 Z 0 1 1 0 1 |
12 |

584 | For creating a ( boldsymbol{p}-boldsymbol{n} ) junction, A. we take one slab of p-type semiconductor and physically join it to another n-type semiconductor B. continuous contact at the atomic level is necessary. C. two macroscopic smooth flat slabs can be used D. None of these |
12 |

585 | There is a sudden increase in current in zener diode is A. Due to rupture of bonds B. Resistance of deplection layer becomes less c. Due to high doping D. Due to less doping |
12 |

586 | State whether given statement is True or False
In p-njunction diode, the forward bias current is very small as compared to the reverse bias current. |
12 |

587 | An experiment is performed to determine the ( I-V ) characteristics of a Zener diode, which has a protective resistance of ( R=100 Omega ), and a maximum power of dissipation rating of ( 1 W . ) The minimum voltage range of the DC source in the circuit is A. ( 0-24 V ) В. ( 0-5 V ) ( begin{array}{ll}c-12 V & V \ V V & -0.12end{array}-12 ) D. ( 0-8 V ) |
12 |

588 | Assertion The various energy bands in a solid may or may not overlap depending on the structure of the solid. Reason If they do not overlap then the intervals between them represent energies which the electrons in the solid cannot have. 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 |

589 | When an impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor A . increases B. decreases c. remains the same D. becomes zero |
12 |

590 | 9. Which of the following is biased? (a) et 5 (6) * 10 +sv than (C) – 12 VKA (d) A SR 6-10 V (AIEEE 2006) |
12 |

591 | What are extrinsic semiconductors? Write two differences between the two types of extrinsic semiconductors. |
12 |

592 | A semi conductor device with both active and passive electronic elements diffused into a silicon water to form a functional circuit is called. A. Thin-film circuit B. Integrated circuit c. Hybrid-circuit D. Thick-film circuit |
12 |

593 | In the circuit shown in figure, the diode is ideal. The potential difference between A and B is? A. ( V / 4 ) B. c. zero D. ( V / 2 ) |
12 |

594 | The gate for which output is high, if at least one input is low is A. NAND в. NOR c. AND D. or |
12 |

595 | If the input frequency of a full wave rectifier is ( 50 H z ) ac. Its output frequency is A. ( 50 H z ) pulsating dc B. ( 100 H z ) pulsating do c. ( 200 H z ) pulsating dc D. ( 500 H z ) pulsating dc |
12 |

596 | Explain the term ‘doping’ | 12 |

597 | In reverse biasing A. large amount of current flows B. potential barrier across junction increases C. depletion laver resistance increases D. no current flows |
12 |

598 | A potential barrier of ( 0.3 mathrm{V} ) exists across a p-njunction. An electron with speed ( 5 times 10^{5} m / s e c ) approaches this p-n junction from n-side, what will be its speed on entering the p-side? A ( .4 .8 times 10^{5} mathrm{m} / mathrm{sec} ) В. ( 3.8 times 10^{5} mathrm{m} / mathrm{sec} ) c. ( 5.8 times 10^{5} mathrm{m} / mathrm{sec} ) D. ( 6.8 times 10^{5} mathrm{m} / mathrm{sec} ) |
12 |

599 | The slope of plate characteristic and mutual characteristic curves of a triode value is ( 0.02 mathrm{mA} / mathrm{V} ) and ( 1 mathrm{mA} / mathrm{V} ). The amplification factor of triode value is: A ( .2 times 10^{8} ) B. 20 c. 50 D. 40 |
12 |

600 | What is light emitting diode (LED)? Explain its working principle and state factors on which the colour of light emitted by it depends. | 12 |

601 | Which type of semi-conductor is formed when a trivalent impurity is dopped in a pure semiconductor? |
12 |

602 | f the lattice constant of this semiconductor is decreased, then ( mathbf{A} cdot ) all ( E_{c}, E_{g}, E_{v} ) increases B. ( E_{c} ) and ( E_{v} ) increases, but ( E_{g} ) decreases ( mathrm{C} cdot E_{c} ) and ( E_{v} ) decreases, but ( E_{g} ) increases. D. all ( E_{c}, E_{g}, E_{v} ) decreases. |
12 |

603 | Carbon, Silicone, and Germanium al have the same number of electrons in an outer most shell. Explain? |
12 |

604 | Which of the following is not an advantage of Integrated Circuits (ICs). A. Extremely small in size B. High power consumption c. Low cost D. Less weight |
12 |

605 | An npn transistor receives voltage to the collector terminal and ( _{-}-_{-}-_{-}-_{-}- ) voltage to the base terminal for proper operation A. positive, positive B. positive, negative c. negative, positive D. negative, negative |
12 |

606 | a speparanationa varies as follows. ( 1 / 1 ) What 1 ( M ) |
12 |

607 | The value of ( beta ) of a transistor is ( 19 . ) The value of ( alpha ) will be A . 0.93 B. 0.98 ( c .0 .99 ) D. 0.95 |
12 |

608 | The band gap for a pure semiconductor is ( 2.1 e V . ) The maximum wavelength of a photon which is able to create a hole- electron pair is nearly: A. ( 600 n m ) B. 590 nm c. 400 n ( m ) D. 200nm |
12 |

609 | The hole in a p-type semiconductor is A. an electron deficiency B. an electron excess c. an atom deficiency D. positive ion |
12 |

610 | The junction area is kept much larger in a solar cell A. for solar radiation to be incident because we are interested in more power. B. for solar radiation to be incident because we are interested in less power C. for solar radiation to be properly reflected from the junction. D. None of these. |
12 |

611 | Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances. | 12 |

612 | Consider the following statements A and B identify the correct statement from the following. A) The width of the depletion layer in a p-njjunction diode increases in forward bias. B) In an intrinsic semiconductor, the Fermi energy level is exactly in the middle of the forbidden gap. A. A is true and B is false. B. Both A and B are false c. A is false and B is true D. Both A and B are true |
12 |

613 | 53. The figure shows a combination of logic gates. To what single gate is this combination equivalent? (a) EX-NOR (b) NOR Input (c) EX-OR (d) OR IL Output M |
12 |

614 | Energy band gap between valence band and conduction band for semiconductor is: A. approximately 1 ev B. less than conductors c. equal to conductors D. more than insulator |
12 |

615 | What is the energy band gap of: (i) silicon and (ii) germanium |
12 |

616 | The following arrangement performs the logic function of ( _{-}-_{-}-_{-}-_{-} ) gate All the gates present above are NAND gate ( A cdot A N D ) B. OR c. NAND D. EXOR |
12 |

617 | The logic expression which is NOT true in Boolean algebra is ( mathbf{A} cdot[overline{1}+overline{1}] cdot 1=0 ) В. ( [overline{1}+0] .1=0 ) c. ( [overline{1}+0] . overline{1}=0 ) D. ( [1+1] .1=0 ) |
12 |

618 | A zener diode voltage regulator operated in the range ( 120-180 V ) produces a constant supply of ( 110 V ) and ( 250 m A ) to the load. If the maximum current is to be equally shared between the load and zener, then the values of series resistance ( left(R_{S}right) ) and load resistance ( left(R_{L}right) ) are: ( mathbf{A} cdot R_{L}=70 Omega ; R_{S}=280 Omega ) B . ( R_{L}=440 Omega ; R_{S}=140 Omega ) C ( . R_{L}=140 Omega ; R_{S}=440 Omega ) ( mathbf{D} cdot R_{L}=280 Omega ; R_{S}=70 Omega ) |
12 |

619 | Explain the working of P-Njunction diode in forward and reverse biased mode |
12 |

620 | A change of ( 8 m A ) in the emitter current brings a change of ( 7.9 m A ) in the collector current. The value of ( beta ) is A. ( 79 / 80 ) в. ( 80 / 79 ) c. 79 D. 80 |
12 |

621 | In an n-type semiconductor, the Fermi- energy level lies: A. in the forbidden energy gap nearer to the conduction band B. in the forbidden energy gap nearer to the valence band C. in the middle of forbidden energy gap D. outside of the forbidden energy gap |
12 |

622 | In the circuit shown below, ( V_{A} ) and ( V_{B} ) are the potentials at ( A ) and ( B, R ) is the equivalent resistance between A and B, ( S_{1} ) and ( S_{2} ) are switches, and the diodes are idea This question has multiple correct options ( mathbf{A} cdot ) if ( V_{A}>V_{B}, S_{1} ) is open and ( S_{2} ) is closed then ( R=8 Omega ) B. if ( V_{A}>V_{B}, S_{1} ) is closed and ( S_{2} ) is open then ( R=12.5 Omega ) C. if ( V_{A}>V_{B}, S_{1} ) is open and ( S_{2} ) is closed then ( R=12.5 Omega ) D. if ( V_{A}>V_{B}, S_{1} ) is closed and ( S_{2} ) is open then ( R=8 Omega ) |
12 |

623 | A ( p ) -type semiconductor has acceptor levels 57 me ( V ) above the valance band. The maximum wavelength of light required to create a hole is (Planck’s constant ( left.h=6.6 times 10^{-34} J-sright) ) A ( .57 AA ) В. ( 57 times 10^{-3} dot{A} ) c. 217100 月 D . ( 11.61 times 10^{-33} dot{A} ) |
12 |

624 | Among the following, one statement is not correct when a junction diode is in forward bias A. the width of depletion region decreases. B. free electron on n- side will move towards the junction c. holes on p-side move towards the junction D. electrons on n-side and holes on p-side will move away from junction. |
12 |

625 | For what value of ( A, B ) and ( C . ) The output of ( Y=1 ) A. 001 B. 101 ( c cdot 100 ) D. 010 |
12 |

626 | Write the logic symbols and prepare the truth tables of the following gates. (i) AND (ii) NOR. |
12 |

627 | The truth table for expression is the given Boolean expression is [ (A+B) cdot overline{(A cdot B)}=1 ] A. begin{tabular}{|c|c|c|} hline( A ) & ( B ) & ( Y ) \ hline 1 & 0 & 0 \ 1 & 1 & 1 \ 0 & 1 & 0 \ 1 & 0 & 0 \ hline end{tabular} в. begin{tabular}{|c|c|c|} hline( A ) & ( B ) & ( Y ) \ hline 1 & 1 & 1 \ 0 & 0 & 1 \ 1 & 0 & 0 \ 1 & 0 & 1 \ hline end{tabular} c. begin{tabular}{|c|c|c|} hline( A ) & ( B ) & ( Y ) \ hline 0 & 0 & 1 \ 1 & 0 & 0 \ 0 & 1 & 0 \ 1 & 1 & 0 \ hline end{tabular} D. begin{tabular}{|c|c|c|} hline( A ) & ( B ) & ( Y ) \ hline 1 & 1 & 0 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 0 & 0 & 0 \ hline end{tabular} |
12 |

628 | Person who use boolean algebra for describing the operation of logic gates first was A . Boole B. Shannon c. schottky D. zener |
12 |

629 | A Truth table is given below. The logic gate having following truth table is ( A quad B quad Y ) ( begin{array}{lll}0 & 1 & 1end{array} ) ( 0 quad 0 ) ( 0 quad 1 quad 0 ) 10 A. NAND gate B. NOR gate c. AND gate D. OR gate |
12 |

630 | Write one main use of Zener diode. | 12 |

631 | When light shines on a ( boldsymbol{p}-boldsymbol{n} ) junction diode, the current ( (I) v s . ) voltage ( (V) ) is observed as in the figure below: In which quadrant(s) does the diode generate power, so that it can be used as a solar cell? A . Quad 1 only c. Quad 4 only D. Quad 1 and 4 onl |
12 |

632 | www 13. In the circuit shown, A and 40A B represent two inputs and C represents the output. The circuit Boat represents (a) NAND gate (b) OR gate (c) NOR gate (d) AND gate (AIEEE 2008) |
12 |

633 | In a full wave rectifier in which input voltage is represented by ( V=V_{M} sin omega t ) then peak inversion voltage of non conducting diode will be? A. ( -V_{M} ) B. ( V_{M} / 2 ) с. ( 2 V_{M} ) D. 0 |
12 |

634 | In common base circuit of a transistor, current amplification factor is 0.95 Calculate the emitter current if base current is ( 0.2 mathrm{mA} ) A . ( 2 mathrm{mA} ) B. ( 4 mathrm{m} ) ( c .6 m A ) D. ( 8 mathrm{m} ) |
12 |

635 | A capacitor is to be provide smoothing for a half wave rectifier. In which of the following diagrams is capacitor correctly connected? ( A ) B. ( c ) ( D ) |
12 |

636 | The current gain ( (beta) ) of a transistor in common base mode is ( 40 . ) To change the collector current by ( 160 mathrm{mA} ), the necessary change in the base current is (at constant ( mathbf{V}_{C E} ) ) A. ( 0.25 mu ) B. ( 4 mu ) A ( c cdot 4 m A ) D. ( 40 mathrm{mA} ) |
12 |

637 | 20 18. The 1-V characteristic of an LED is (b) oooo Red Yellow Green Blud (R) (Y) (G)(B) (JEE Main 2013) |
12 |

638 | The working transistor with its three legs marked ( mathrm{P}, mathrm{Q}, ) and ( mathrm{R} ) is tested using a multimeter. No conduction is found between ( P & Q . ) By connecting the common (negative) terminal of the multimeter to ( mathrm{R} ) and the other (positive) terminal to ( mathrm{P} ) or ( mathrm{Q}, ) some resistance is seen on the multimeter. The correct statement for the transistor is A. It is an n-p-n transistor with ( mathrm{R} ) as base B. It is a p-n-p transistor with ( mathrm{R} ) as collector C. It is a p-n-p transistor with ( R ) as emitter D. It is an n-p-n transistor with ( mathrm{R} ) as collector |
12 |

639 | The outputs of two NOT gates are fed to a NOR gate. Draw the logic circuit of the combination of gates. Give its truth table. Identify the gate represented by this combination. |
12 |

640 | The follwoing combined logic gate diagram is eqivalent to A. NOR gate B. oR gate c. AND gate D. NAND gate |
12 |

641 | In an intrinsic semiconductor, conductivity is due to A. doping B. breaking of covalent bonds c. free electrons D. holes |
12 |

642 | What is biasing a diode? Write two differences between the two kinds of biasing. |
12 |

643 | In a circuit shown in the value of ( beta ) is 100. ( I_{c}=1.5 m A . ) The transistor is in A. Active state B. Cut off state c. Saturation state D. Breakdown state |
12 |

644 | A Ge specimen is doped with ( A l ). The concentration of acceptor atoms is ( sim ) ( 10^{21} ) atoms ( / m^{3} . ) Given that the intrinsic concentration of electron-hole pairs is ( sim 10^{19} / m^{3}, ) the concentration of electrons in the specimen is ( mathbf{A} cdot 10^{17} / m^{3} ) B . ( 10^{15} / m^{3} ) c. ( 10^{4} / m^{3} ) D. ( 10^{2} / m^{3} ) |
12 |

645 | The Base-Emitter voltage for a CE transistor used as an amplifier is ( 0.02 mathrm{V} ) An input signal given to this transistor results in a change of base current by, ( 20 mu A ) and a changes of ( 2 mathrm{mA} ) takes place in the collector current. Calculate the following quantities: 1. Input resistance. 2. A.C. current gain 3. Transconductance. 4. If the load resistance is ( 5 k Omega ) what will be the voltage gain. |
12 |

646 | To obtain a good quality DC from AC we shall use This question has multiple correct options A . RC filter B. LC filter c. ( pi ) filter D. Butterworth filter |
12 |

647 | Which of the following is the correct graph showing ( boldsymbol{V}-boldsymbol{I} ) characteristics for an ideal ( P N ) junction diode? |
12 |

648 | In a transistor A. the emitter has the least concentration of impurity B. the collector has the least concentration of impurity C. the base has the least concentration of impurity D. all the three regions have equal concentrations of impurity |
12 |

649 | The current in the given circuit is: (Given barrier potential of the diode = ( 0.5 V) ) ( mathbf{A} cdot 4 m A ) B. ( 4 A ) c. ( 4 mu A ) D. ( 40 mu A ) |
12 |

650 | An unknown transistor needs to be identified as a ( n p n ) or ( p n p ) type. multimeter, with ( + )ve and -ve terminals, is used to measure resistance between different terminals of transistor. If terminal 2 is the base of the transistor then which of the following is correct for a ( p n p ) transistor? A. ( + )ve terminal ( 1,-v e ) terminal 2 , resistance high ( 2,-v e ) terminal B. ( + )ve terminal ( 3, ) resistance low c. ( + )ve terminal ( 3,-v e ) terminal 2 , resistance high D. ( + )ve terminal ( 2, ) -ve terminal ( 1, ) resistance high |
12 |

651 | If ( N^{A} ) is number density of acceptor atoms added and ( N^{D} ) is number density of donor atoms added to a semiconductor, ( n^{e} ) and ( n^{n} ) are the number density of electrons and holes in it,then A ( cdot n^{e}=N^{D}, n^{n}=N^{A} ) B . ( n^{e}=N^{A}, n^{h}=N^{D} ) c. ( N^{A}+n^{n}=N^{D}+n^{text {ศ }} ) D. ( n^{e}+N^{A}=n^{n}+N^{D} ) |
12 |

652 | The depletion region is A. region of opposite charges. B. neutral region. C . region of infinite energy. D. region free of charge carriers. |
12 |

653 | Fermi energy level for ( boldsymbol{p}- )type extrinsic semiconductors lies A . At middle of the band gap B. close to conduction band c. close to valence band D. None of the above |
12 |

654 | The most widely used semiconductors are (i) silicon (ii) germanium (iii) phosphorus (iv) arsenic A ( cdot ) (i) and (ii) B. (ii) and (iii) c. (iii) and (iv) D. (i), (ii), (iv) (iii) |
12 |

655 | In the circuit shown, the diodes are ideal. ( A_{1} ) and ( A_{2} ) are ammeters of resistance ( 5 Omega ) each. The potentials of the points ( A, B, C ) and ( D ) are ( V_{A}, V_{B}, V_{C} ) and ( V_{D} ) respectively. ( left|boldsymbol{V}_{boldsymbol{A}}-boldsymbol{V}_{boldsymbol{B}}right|=mathbf{1 0} boldsymbol{V} ) This question has multiple correct options A. ( A_{1} ) and ( A_{2} ) will always show the same reading B. the readings of ( A_{1} ) and ( A_{2} ) will depend on whether ( V_{A}>V_{B} ) or ( V_{A}V_{B}, A_{1} ) will show no deflection |
12 |

656 | Two similar p-njunctions can be connected in three different ways as shown in the figures. The two connections across which the potential difference is same are ( a) ) ( b) ) ( c ) A. circuits a and b B. circuits b and c C. circuits a and c D. all the circuits |
12 |

657 | A semiconductor has an electron concentration of ( 8 times 10^{13} ) per ( c m^{3} ) and ( a ) hole concentration of ( 5 times 10^{12} ) per ( c m^{3} ) The electron mobility is ( 25000 c m^{2} V^{-1} s^{-1} ) and the hole mobility is ( 100 mathrm{cm}^{2} V^{-1} s^{-1} . ) Then A. The semiconductor is ( n ) -type B. The conductivity is 320 ( mathrm{m} ) mho ( mathrm{cm}^{-1} ) c. Both (a) and (b) D. None of the above |
12 |

658 | A man wants to measure current ( sim boldsymbol{m} boldsymbol{A} ) He should use A. photo multiplier tube B. photo cell and amplifier c. photo multiplier tube and amplifier D. photo cell and two stage amplifier |
12 |

659 | The valency of impurity element for making n-type semiconductor is A . 3 B. 5 ( c cdot 4 ) ( D ) |
12 |

660 | A transistor is a two junction and two terminal device A. True B. False |
12 |

661 | The transfer ratio ( beta ) of a transistor is 50 The input resistance of the transistor when used in the common emitter mode is ( 1 K omega ).The peak value of the collector alternating current for an input peak voltage of ( 0.01 V ) is A. ( 100 mu A ) в. ( 500 mu A ) c. ( 0.01 mu A ) D. ( 0.25 mu A ) |
12 |

662 | If a rod has resistance 4 ohm and if rod is turned as half circle, then the resistance along diameter is A. 1.56 ohm B. 2.44 ohm c. 4 ohm D. 2 ohm |
12 |

663 | Direction of electric field in P-N junction diode is A. from P-side to N-side B. from N-side to P-side c. randomly oriented D. electric field does not exist |
12 |

664 | In a current voltage plot of a ( mathrm{p}-mathrm{n} ) junction, find out the correct statement from the following? A. A p-njunction is essentially nonconducting when it is forward biased and highly conducting when it is reverse biased B. A p-njunction is highly conducting when it is forward biased and essentially nonconducting when it is reverse biased C. A p-njunction is highly conducting when it is forward biased as well as when it is reverse biased D. A p-njunction is essectially nonconducting when it is forward biased as well as when it is reverse biased |
12 |

665 | Construct the logic symbol, Boolean expression, circuit diagram and truth table for an OR gate. |
12 |

666 | Assertion STATEMENT-1: If output of a AND gate is fed to OR gate, it is called NOR gate. Reason STATEMENT-2: If output of a AND gate is fed to NOT gate, it is called NAND gate. A. Statement-1 is True, Statement-2 is True; Statementis a correct explanation for Statement- B. Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement- c. statement-1 is True, Statement-2 is False D. Statement-1 is False, Statement-2 is True |
12 |

667 | In a transistor, forward bias is always smaller than the reverse bias. This is done to : A. Maintain constant current supply B. get good output c. Avoid excessive heating of transistor D. Maintain flow of majority charge carriers |
12 |

668 | With reference to semiconductor devices, define a p-type semiconductor and a Zener diode. What is the use of a Zener diode? |
12 |

669 | Find the minimum load resistance which can be used for the zener diode as shown in figure. Given, ( boldsymbol{V}_{boldsymbol{Z}}= ) ( mathbf{1 0} boldsymbol{V}, boldsymbol{R}_{Z}=mathbf{0} mathbf{Omega}, boldsymbol{R}=mathbf{4 5 0 Omega}, boldsymbol{I}_{Z}(boldsymbol{m} boldsymbol{i n})= ) ( 2 m A ) and ( I_{Z}(max )=60 m A ) A . ( 0 Omega ) B. ( 333.3 Omega ) c. ( 31.95 Omega ) D. ( 319.5 Omega ) |
12 |

670 | The vacancy created due to the absence of an electron in the valence band of a semiconductor is called a A . electron B. hole c. proton D. position |
12 |

671 | The following circut represents A. OR gate B. XOR gate C. AND gate D. NAND gate |
12 |

672 | To make a p-type semiconductor, an intrinsic semiconductor is doped with A. Gallium or indium B. Arsenic or phosphorus c. Aluminium or boron D. Both (1) and (3) |
12 |

673 | Write a short note on P-type semiconductor | 12 |

674 | Which of the following statement is not true? A. The resistance of intrinsic semiconductors decreases with increase to temperature B. Doping pure Si with trivalent impurities gives p-type semiconductor c. The majority carriers in n-type semiconductors are holes D. A p-njunction can act as a semiconductor diode |
12 |

675 | Find the output ( F ) of the logic circuit given below |
12 |

676 | Heavily doped p-n junction diode which emits light when it is forward biased is/are: A. zener diode B. photo-diode c. light emitting diode D. all of the above |
12 |

677 | Name the gate, which represents the Boolean expression ( boldsymbol{Y}=boldsymbol{A} cdot boldsymbol{B} ) A. NAND B. AND c. Not D. NOR |
12 |

678 | An intrinsic semiconductor has ( 10^{18} / m^{3} ) free electron and is doped with pentavalent impurity of ( 10^{24} / m^{3} . ) Then the free electrons density order increase by A .4 B. 3 c. 5 D. 6 |
12 |

679 | What is the type of the semiconductor, for the energy band diagram shown in the figure? A. N-type semiconductor B. P-type semiconductor c. Intrinsic semiconductor D. Both ( N ) and ( P ) type semiconductors |
12 |

680 | The forbidden gap for a pure silicon at the room temperature is eV. A. Less than one B. 1.1 ( c cdot 3 ) D. |
12 |

681 | The barrier potential of a p-njunction depends on: (a) type of semi conductor material (b) amount of doping (c) temperature Which one of the following is correct? A. (a) and (b) only B. (b) only c. (b) and (c) only D. (a), (b) and (c) |
12 |

682 | In an unbiased ( p-n ) junction A. Potential at ( p ) is more than that at ( n ) B. Potential at ( p ) is less than that at ( n ) C. Potential at ( p ) is equal to that at ( n ) D. Potential at ( p ) is +ve and that at ( n ) is -ve |
12 |

683 | Draw the logic symbol of AND gate. | 12 |

684 | An n-p-n transistor conducts when A. both collector and emitter are positive with respect to the base. B. collector is positive and emitter is negative with respect to the base. C . collector is positive and emitter is at same potential as the base. D. both collector and emitter are negative with respect to the base. |
12 |

685 | The output of OR gate is 1: A. If either one or both inputs are 1 B. Only if both inputs are 1 C. If either input is zero D. If both inputs are zero |
12 |

686 | Which of the following sources gives best monochromic light? A. A candle B. A bulb c. A mercury tube D. A laser |
12 |

687 | Figure shows the circuit of an electronic device (i) Which electronic device: a rectifier, an amplifier or an oscillator does the circuit represent? (ii) State where the input voltage is applied and where the output voltage is available. (iii) Compare the output voltage of this circuit with its input voltage. |
12 |

688 | With the help of circuit diagram, explain the V-1 characteristics of p-n junction diode in forward biasing. | 12 |

689 | What is the energy band gap of silicon and germanium respectively in ( e V ) ? A . 1.1,0.7 в. 0.7,1.1 c. -0.7,-1.1 D. -1.1,-0.7 |
12 |

690 | Calculate the mutual conductance ( g_{m} ) of the triode valve? A ( .5 .33 times 10^{-3} mathrm{ohm}^{-1} ) B. ( 53.3 times 10^{-3} ) ohm ( ^{-1} ) c. ( 4.32 times 10^{-3} mathrm{ohm}^{-1} ) D. ( 5.00 times 10^{-3} mathrm{ohm}^{-1} ) |
12 |

691 | A pure germanium crystal at absolute zero is: A. An insulator. B. A good conductor. c. A semiconductor D. None of the above |
12 |

692 | Which logic gate is represented by the following logic gates? A. NOR B. NAND ( c . ) AND D. on |
12 |

693 | The necessary condition in making of a junction transistor (E-emitter, B-base and C-collector) A. ( E ) is heavily doped, ( B ) is thin and lightly doped and ( C ) is moderately doped B. E and C are lightly doped and B is thick and heavily doped C. ( mathrm{E} ) and ( mathrm{B} ) are heavily doped and ( mathrm{C} ) is lightly doped D. ( mathrm{E} ) and ( mathrm{B} ) are lightly doped an ( mathrm{C} ) is heavily doped |
12 |

694 | W onductor Which of the energy band diagrams shown in the figure corresponds to that of a semiconductor? СВ (a) (b) VB VB СВ СВ E>> T VB E. = KT VB 16 Two PN iunctions can be connen |
12 |

695 | For the given circuit shown in fig to act as full wave rectifier – ac input should be connected across and ( ldots ldots . ) the d.c. output would appear across ……… and ( A cdot A, C, B, D ) ( B . B, D, A, C ) ( mathbf{c} cdot A, B, C, D ) ( D cdot C, A, D, B ) |
12 |

696 | Barrier potential of a p-njunction diode does not depend on: A. Diode design B. Doping density c. Temperature D. Forward bias |
12 |

697 | An n-p-n transistor power amplifier in ( mathrm{C} ) E configuration gives A. Voltage amplification only B. Current amplification only c. Both current and voltage amplification D. only power gain of unity |
12 |

698 | In a semiconductor at room temperature A. the valence band is partially empty and the conduction band is partially filled. B. the valence band is completely empty and the conduction band is partially filled. C. the valence band is completely filled. D. the conduction band is completely empty. |
12 |

699 | Explain with the help of a circuit diagram the working of a photo diode. Write briefly how it is used to detect the optical signals. | 12 |

700 | Which part in the diagram shows band gap A. B. A ( c . ) в D. A and C |
12 |

701 | ( dots ) the function ( Z ) of ( X ) and ( Y ) represented by given figure is : ( A ) begin{tabular}{|c|c|c|} hline( X ) & ( Y ) & ( Z ) \ hline 0 & 0 & 0 \ 0 & 1 & 0 \ 1 & 0 & 1 \ 1 & 1 & 1 \ hline end{tabular} B. begin{tabular}{|c|c|c|} hline( X ) & ( Y ) & ( Z ) \ hline 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 0 \ 1 & 1 & 0 \ hline end{tabular} ( c ) begin{tabular}{|c|c|c|} hline( X ) & ( Y ) & ( Z ) \ hline 0 & 0 & 1 \ 0 & 1 & 0 \ 1 & 0 & 1 \ 1 & 1 & 0 \ hline end{tabular} D. None of these |
12 |

702 | In the depletion region of an unbiased ( mathrm{P} ) Njunction diode there are |
12 |

703 | Explain the working of a diode as a half wave rectifier. | 12 |

704 | 29. In a transistor circuit shown here the base current is 35 uA. The value of the resistor Rg is (a) 123.5 k12 (b) 257 k 2 (c) 380.05 k 2 (d) None of these R R, 9V |
12 |

705 | Which type of gate the following truth table represents? ( begin{array}{lll}text { Input } & text { Input } & text { Output } \ A & B & Q \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0end{array} ) ( mathbf{A} cdot ) NOT B. AND ( c cdot ) OR D. NAND |
12 |

706 | Select the output ( Y ) of the combination of gates shown in figure for inputs ( boldsymbol{A}= ) ( mathbf{1}, boldsymbol{B}=mathbf{0} ; boldsymbol{A}=mathbf{1}, boldsymbol{B}=mathbf{1} ) and ( boldsymbol{A}=mathbf{0}, boldsymbol{B}= ) respectively. A ( .(0,1,1) ) в. (1,0,1) c. (1,1,1) D. (1,0,0) |
12 |

707 | 2. Electrical conductivity of a semiconductor (a) Decreases with the rise in its temperature (b) Increases with the rise in its temperature (c) Does not change with the rise in its temperature (d) First increases and then decreases with the rise in its temperature |
12 |

708 | Fill in the blank. In a Ruby laser, the colour of laser light is due to A. Oxygen B. Aluminium c. xenon D. Chromium |
12 |

709 | Electrical conduction in a semiconductor takes place due to A. electrons only B. holes only c. both electrons and holes D. neither electrons nor holes |
12 |

710 | Vuuput LUI Siligie uute mpul gale is that of AND gate. 14. The diagram of a logic circuit is given below. The output F of the circuit is represented by Wo of destin wo myam (a) W (X+Y) (c) W + (XY) – (b) W.( X Y) (d) W+ (X+Y) |
12 |

711 | Mention important characteristics and applications of a diode. | 12 |

712 | 57. What is the output in the figure? A Do A . (a) A B (b) A. B e (c) A.B (d) A.B. |
12 |

713 | The following is NOT equal to 0 in the Boolean algebra is ( mathbf{A} cdot overline{bar{A} cdot 0} ) в. ( A . bar{A} ) c. ( A . ) D. ( overline{A+bar{A}} ) |
12 |

714 | In the Boolean algebra: ( boldsymbol{A}+boldsymbol{B} ) is equal to: ( A cdot A+B ) B. ( bar{A}+bar{B} ) c. ( overline{A . B} ) D. ( bar{A} . bar{B} ) |
12 |

715 | The use of zener diode is as | 12 |

716 | (a) A student wants to use two ( p-n ) junction diodes to convert alternating current into direct current. Draw the labelled circuit diagram she would use and explain how it works. (b) Give the truth table and circuit symbol for NAND gate. |
12 |

717 | The ( beta ) of a transistor is ( 74 . ) It is connected in common base configuration. If the emitter current is ( 5 m A, ) the collector current is (approximately) A. ( 0.45 mathrm{mA} ) B. ( 4.93 mathrm{mA} ) ( mathbf{c} .370 mathrm{mA} ) D. ( 5 m A ) |
12 |

718 | State True or False: n-p-n transistors exhibit higher transconductance and speed than ( mathrm{p}-mathrm{n}-mathrm{p} ) transistors. A. True B. False |
12 |

719 | For a transistor to work as an amplifier: A. its emitter junction is in reverse bias and collector junction is in forward bias B. the transistor must have breakdown region C. its emitter junction is in forward bias and collector junction is in reverse bias D. its emitter and collector junction are in forward bias |
12 |

720 | NOR gate is the series combination of A. NOT gate followed by OR gate. B. OR gate followed by NOT gate. C. AND gate followed by OR gate. D. OR gate followed by AND gate. |
12 |

721 | Assertion The energy bands in a solid correspond to the energy levels in an atom. Reason An electron in a solid can have only energies that fall with these energy bands. 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 |

722 | If ( n_{p} ) and ( n_{e} ) are the number of holes and conduction electrons in an intrinsic semiconductor then A ( cdot n_{p}>n_{e} ) в. ( n_{p}=n_{e} ) c. ( n_{p}<n_{e} ) D ( cdot n_{p} neq n_{e} ) |
12 |

723 | Identify the electronic components from the following symbols. Write any one difference between them. |
12 |

724 | The input characteristics of a transistor in ( C E ) mode is the graph obtained by plotting ( mathbf{A} cdot I_{B} ) against ( V_{B E} ) at constant ( V_{C E} ) B. ( I_{B} ) against ( V_{C E} ) at constant ( V_{B E} ) C ( cdot I_{B} ) against ( I_{C} ) at constant ( V_{C E} ) D. ( I_{V} ) against ( I_{C} ) at constant ( V_{B E} ) |
12 |

725 | A photoelectric cell emits electrons when illuminated by a ( 60 ~ W ) bulb. If the same cell is illuminated by replacing it with a ( 40 W ) bulb, the observation that can be made is A. No photoelectric effect takes place B. Number of photoelectrons increases c. The kinetic energy of photoelectrons decreases D. Number of photoelectrons decreases |
12 |

726 | In a p-type semiconductor, the electron current is ( _{-}-_{-}-_{-}- ) the hole current. A. equal to B. less than c. greater than D. none of the above |
12 |

727 | The maximum wavelength of photons that can be detected by a photo-diode, which is made of a semiconductor of band gap ( 2 e V ) is about : ( mathbf{A} cdot 620 n m ) B. 700 nm ( c .740 n m ) D. ( 860 n m ) E. ( 1240 n m ) |
12 |

728 | In the half wave rectifier circuit operating from ( 50 H z ) mains frequency, the fundamental frequency in the ripple would be ( mathbf{A} cdot 25 H z ) B. ( 50 mathrm{Hz} ) c. ( 70.7 H z ) D. ( 100 H z ) |
12 |

729 | The minimum potential difference between the base and emitter required to switch a silicon transistor ( O N ) is approximately ( mathbf{A} cdot 1 V ) B. ( 3 V ) c. ( 5 V ) D. ( 4.2 V ) |
12 |

730 | Which logic gates mentioned below have the output value ‘O’ when both the inputs are 1 ( A cdot O R, N A N D ) B. AND, NOR c. AND, OR D. NOR, NAND |
12 |

731 | What is the output of the combination? | 12 |

732 | When is a transistor said to be in active state? Draw a circuit diagram of a p-np transistor and explain how it works as a transistor amplifier. Write clearly, why in the case of a transistor (i) the base is thin and lightly doped and (ii) the emitter is heavily doped. |
12 |

733 | What would be the output of the circuit whose boolean expression ( boldsymbol{Y}=boldsymbol{A} overline{boldsymbol{B}}+ ) ( A B ) when ( A=1, B=0 ? ) ( A ) B. c. Both (A) & (B) D. None of these |
12 |

734 | The highest energy band which is filled at zero Kelvin is called A. conduction band B. valence band c. insulation band D. filled band |
12 |

735 | Write the two processes that take place in the formation of a ( boldsymbol{p}-boldsymbol{n} ) junction. Explain with the help of a diagram, the formation of the depletion region and barrier potential in a ( p-n ) junction. |
12 |

736 | Suppose a pure Si crystal has ( 5 times 10^{28} ) atoms ( m^{-3} . ) it is doped by 1 ppm concentration of pentavalent As. Calculate the number of electrons and holes. Given that ( n_{1}=1.5 times 10^{16} m^{-3} ) |
12 |

737 | If ( alpha ) -current gain of a transistor is 0.98 What is the value of ( beta ) -current gain of the transistor? A . 0.49 B. 49 c. 4.9 D. 5 |
12 |

738 | ( begin{array}{ccc}boldsymbol{A} & boldsymbol{B} & boldsymbol{Q} \ 0 & 0 & 0 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 1end{array} ) The truth table is given above for which of the following gates is correct A. NAND gate B. OR gate c. AND gate D. NOT gate |
12 |

739 | The conductivity of a semi conductor can be increased by: A. Heating the semi conductor B. Doping the semi conductor c. Both (a) and (b) D. None |
12 |

740 | ILLUSTRATION 31.5 Write the truth table for a NAND gate connected as given in figure. |
12 |

741 | On doping germanium with donor atoms of density ( 10^{17} mathrm{cm}^{-3} ) its conductivity in ( m h o / c m ) will be ( left[text { Given: } mu_{e}=3800 mathrm{cm}^{2} / V-s text { and } n_{i}=right. ) ( left.2.5 times 10^{13} c m^{-3}right] ) A . 30.4 B. 60.8 c. 91.2 D. 121.6 |
12 |

742 | Assertion ( mathbf{A} ) p-njunction with reverse bias can be used as a photodiode to measure light intensity. Reason In a reverse bias condition the current is small but it is more sensitive to changes in incident light intensity. 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 |

743 | In the given figure if ( V_{I N} ) increases then ( boldsymbol{I}_{z} ) will A. change B. decrease ( c . ) increase D. does not change |
12 |

744 | Which of the following statement is not true? A. The resistance of an intrinsic semiconductor decreases with increase in temperature B. Doping pure ( S i ) with trivalent impurities gives ( p ) -type semiconductor C. The majority carriers in n-type semiconductor are holes D. a p-njunction can act as a semiconductor diode |
12 |

745 | The mobility of hole in a semiconductor depend on A. Electric field B. Potential difference c. current D. Mass |
12 |

746 | 12. A working transistor with its three legs marked P. e and R is tested using a multimeter, no conduction 15 found between P and O. By connecting the common (negative) terminal of the multimeter to R and the other (positive) terminal to Por Q, some resistance is seen on the multimeter. Which of the following is true for the transistor? (a) It is a pnp transistor with R as emitter. (b) It is an npn transistor with R as collector. (c) It is an npn transistor with R as base. (d) It is pnp transistor with R as collector. (AIEEE 2008) |
12 |

747 | The photovoltaic effect is the creation of a material upon exposure to light and is a physical and chemical phenomenon. A. voltage or electric current B. voltage c. current D. none of the above |
12 |

748 | The output characteristic of an ( n-p-n ) transistor represent: ( left[I_{C}=text { Collector current, } V_{C E}= ) potential right. difference between collector and emitter, ( boldsymbol{I}_{B}= ) Base current, ( boldsymbol{V}_{boldsymbol{B} boldsymbol{B}}= ) voltage given to base; ( V_{B E}= ) the potential difference between base and emitter ( ] ) A. changes in ( I_{C} ) as ( I_{B} ) and ( V_{B B} ) are changed B. changes in ( I_{C} ) with changes in ( V_{C E}left(I_{B}=text { constant }right) ) c. changes in ( I_{B} ) with changes in ( V_{C E} ) D. changes in ( I_{C} ) as ( V_{B E} ) is changed |
12 |

749 | 27. In a common base amplifier circuit, calculate the change in base current if that in the emitter current is 2 mA and a= 0.98. (a) 0.04 mA (b) 1.96 mA (c) 0.98 mA (d) 2 mA 20 ENDN transistore thanallantan m antan.. olau |
12 |

750 | A common emitter amplifier is designed with ( n ) -p-n transistor ( (alpha= ) 0.99). The input impedance is ( 1 k Omega ) and load is ( 10 k Omega . ) The voltage will be : A . 9900 B. 99 c. 9.9 D. 990 |
12 |

751 | Which of the following law(s) is/are included in Boolean algebra? A. Commutative Law B. Associative Law c. Distributive Law D. All of the above |
12 |

752 | The truth table given in figure represents: begin{tabular}{|c|c|c|} hline ( mathrm{A} ) & ( mathrm{B} ) & ( mathrm{Y} ) \ hline 0 & 0 & 0 \ hline 0 & 1 & 1 \ hline 1 & 0 & 1 \ hline 1 & 1 & 1 \ hline end{tabular} A. AND-Gatt B. NOR – Gate c. NAND – Gate DR – Gat |
12 |

753 | The output of the given circuit in the figure. A. would be zero at all times B. would be like a half-wave rectifier with positive cycles in output C. would be like a half -wave rectifier with negative cycles in output D. would be like that of a full wave rectifier |
12 |

754 | The truth tables of logic gates ( A, B, C, D ) are given here. Identify them correctly. begin{tabular}{|c|c|c|} hline multicolumn{3}{|c|} { Input } & multicolumn{1}{c|} { Output } \ hline ( mathrm{A} ) & ( mathrm{B} ) & ( mathrm{Y} ) \ hline 0 & 0 & 0 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 1 \ hline end{tabular} begin{tabular}{|l|c|c|} hline multicolumn{2}{|c|} { Input } & Output \ hline ( mathrm{A} ) & ( mathrm{B} ) & ( mathrm{Y} ) \ hline 0 & 0 & 0 \ 0 & 1 & 0 \ 1 & 0 & 0 \ 1 & 1 & 1 \ hline end{tabular} begin{tabular}{|l|l|l|} hline multicolumn{2}{|c|} { Input } & multicolumn{1}{|c|} { Output } \ hline ( mathrm{A} ) & ( mathrm{B} ) & ( mathrm{Y} ) \ hline 0 & 0 & 1 \ 0 & 1 & 0 \ 1 & 0 & 0 \ 1 & 1 & 0 \ hline end{tabular} begin{tabular}{|l|c|c|} hline multicolumn{2}{|c|} { Input } & multicolumn{1}{|c|} { Output } \ hline ( mathrm{A} ) & ( mathrm{B} ) & ( mathrm{Y} ) \ hline 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0 \ hline end{tabular} A . A: OR B: AND, C: NOR, D: NAND B. A: OR, ( B: ) NOR, ( C: A N D ) D: NAND C. ( A: A N D ) B: OR, C: NAND, D: NOR D. A: OR B: NOR, C: NAND, D: AND |
12 |

755 | As the temperature of a transistor increases, the collector current will A. increase B. decrease c. remain constant D. depends on the situation |
12 |

756 | The equivalent circuit is : A. NAND gates B. OR gates c. AND gates D. NOR gates |
12 |

757 | The load voltage is approximately constant when a zener diode is A. Forward-biased B. Reverse-biased c. operating in the breakdown region D. Unbiased |
12 |

758 | One way in which the operation of an ( n ) – ( p-n ) transistor differ from that of a ( p-n-p ) transistor is that A. the emitter junction is reverse biased in ( n-p-n ) B. the emitter junction injects minority carriers into the base region of the ( mathrm{p}-mathrm{n}-mathrm{p} ) C. the emitter injects holes into the base of the pnp and electrons into the base region of ( n-p-n ) D. the emitter injects holes into the base of ( n-p-n ) |
12 |

759 | If ( boldsymbol{A}=boldsymbol{B}=mathbf{1}, ) then in terms of Boolean algebra the value of ( boldsymbol{A} . boldsymbol{B}+boldsymbol{A} ) is not equal to ( mathbf{A} cdot B cdot A+B ) в. ( B+A ) ( c . B ) D. ( bar{A} . B ) |
12 |

760 | 35. A transistor is used in a common-emitter mode in an amplifier circuit. When a voltage of 20 mV is added to the base-emitter voltage, the base current changes by 20 uA and the collector current changes by 2 mA. The load resistor is 5 k 2. What is the volume of B? (a) 10 (b) 100 (c) 1000 (d) 106 |
12 |

761 | In an insulator, the energy gap between conduction band and valence band is about A. 0 eV B. 6 eV ( c cdot 1 e V ) D. 0.6 eV |
12 |

762 | In the given circuit the current through Zener Diode is close to : ( mathbf{A} cdot 6.0 m ) в. ( 4.0 mathrm{m} ) А ( c .6 .7 m A ) D. ( 0.0 mathrm{mA} ) |
12 |

763 | The following truth table corresponds to the logic gate ( begin{array}{ccc}mathbf{A} & mathbf{B} & mathbf{X} \ 0 & 0 & 0 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 1end{array} ) A. NAND B. OR C . AND D. xor |
12 |

764 | To obtain n-type extrinsic semiconductor, the impurity element to be added to germanium should be of valency A .2 B. 5 ( c cdot 4 ) ( D ) |
12 |

765 | What is rectifier? Explain with neat circuit diagram the action of semiconductor diode as a full wave rectifier. |
12 |

766 | (i) Write the truth tables of the logic gates market ( boldsymbol{P} ) and ( boldsymbol{Q} ) in the given circuit. (ii) Write the truth table for the circuit |
12 |

767 | In the given circuit, value of ( Y ) is: A . toggles between 0 and 1 B. c. will not execute ( D ) |
12 |

768 | 34. The current gain a of a transistor in common-base mode is 0.995. Its gain Bin the common-emitter mode is nearly (a) 9.5 (b) 1.005 (c) 200 (d) 100 |
12 |

769 | If ( V_{B}=5 V ), then the maximum value of ( R ) so that the voltage ( V ) is above the knee point voltage, should be ( A cdot 0.7 times Omega ) в. 4.3 К. ( c cdot 5 K Omega ) D. 5.7 к. |
12 |

770 | Draw diagram for a P-N junction to obtain reverse bias characteristic curves. Explain the phenomenon of reverse breakdown for a P-N junction in reserve bias state by following processes- (i) Avalanche breakdown (ii) Zener breakdown |
12 |

771 | Doping of silicon with indium leads to which type of semiconductors? |
12 |

772 | To get an output of 1. from the circuit shown in figure the input must be ( mathbf{A} cdot a=0, b=0, c=1 ) B ( . a=1, b=0, c=0 ) ( mathbf{c} cdot a=1, b=0, c=1 ) D . ( a=0, b=1, c=0 ) |
12 |

773 | In a transistor output characteristics commonly used in common emitter con ig ration, the base current ( boldsymbol{I}_{B}, ) the collector current ( I_{C} ) and the collector- emitter voltage ( V_{C E} ) have values of the following orders of magnitude in the active region ( mathbf{A} cdot I_{B} ) and ( I_{C} ) both are in ( mu A ) and ( V_{C E} ) in Volts B. ( I_{B} ) is in ( mu A ), and ( I_{C} ) is in ( m A ) and ( V_{C E} ) in Volts ( mathbf{C} cdot I_{B} ) is in ( m A, ) and ( I_{C} ) is in ( mu A ) and ( V_{C E} ) in ( m V ) D. ( I_{B} ) is in ( m A ), and ( I_{C} ) is in ( m A ) and ( V_{C E} ) in ( m V ) |
12 |

774 | Silicon is not suitable for fabrication of light emitting diodes because it is: A. an indirect band gap semiconductor B. a direct band gap semiconductor c. a wide band gap semiconductor D. none of the above |
12 |

775 | If ( A=1 ) and ( B=0, ) then in terms of Boolean algebra the value of ( A . A+B ) is A . ( A ) B. ( B^{2} ) ( c . B ) D . ( A cdot B ) |
12 |

776 | To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behave like A. a conductor B. a p-type semiconductor c. an n-type semiconductor D. a insulator |
12 |

777 | In positive logic, the logic state 1 corresponds to A. positive voltage B. zero voltage c. lower voltage level D. higher voltage leve |
12 |

778 | A common emitter transistor amplifier has a current gain of ( 50 . ) If the load resistance is ( 4 k Omega, ) and input resistance is ( 500 Omega, ) the voltage gain of amplifier is : A. 100 в. 200 c. 300 D. 400 |
12 |

779 | Which of the following applications is not based on use of ICs? A. Microprocessor chip. B. Laptops and personal computers. c. Mobile phones. D. Transformers |
12 |

780 | If an LED has to emit 662 nm wavelength of light them what should be the band gap energy of its semiconductor? ( boldsymbol{h}= ) ( 6.62 times 10^{-34} mathrm{Js} ) |
12 |

781 | Photo-diode is operated in reverse bias because A. When the diode is reversed biased, no ordinary current flows and the detection of the photo-current is much easier B. When the diode is reversed biased, ordinary current flows and the detection of the photo-current is much easier C. In reverse biased it will conduct a lot of current and can’t detect the small amount of excess current produced by the photoelectric effect D. All of the above |
12 |

782 | As the temperature of a transistor increases, A. The base-emitter voltage required for a given collector current will decrease B. The base-emitter voltage required for a given collector current will increase C. The base-emitter voltage required for a given collector current will remain constant D. The base-emitter voltage required for a given collector current will be indeterminate |
12 |

783 | The output of the combination of the gates shown in the figure is ( mathbf{A} cdot A+A cdot B ) B . ( (A+B) A+bar{B} ) c. ( (A . B)+(bar{A} . bar{B}) ) D. ( (A+B)(overline{A . B}) ) |
12 |

784 | 36. In question 35, the input resistance is (a) 1 ΚΩ (b) 2 ΚΩ (c) 3 kΩ (d) 4 ΚΩ |
12 |

785 | Why is a photo-diode invariably reverse biased, when it is used as a photo- detector? A. The power consumption is much reduced compared to reverse biased condition B. Electron hole pairs can be produced by the incident photons only if the photo diode is reverse biased C. Light variations can be converted into current variations only if the photo diode is reverse biased D. When photons are incident on the diode, the fractional change in the reverse current is much greater than the fractional change in the forward current E. The photo diode will be spoilt if it is operated under forward biased condition |
12 |

786 | 3. A photodetector is made from a semiconductor In 0.53 Ga 0.47As with E, = 0.73 eV. What is the maximum wavelength, which it can detect (a) 1000 nm (b) 1703 nm (c) 500 nm (d) 173 nm |
12 |

787 | Two ideal junction diodes ( D_{1}, D_{2} ) are connected as shown in the figure. A ( 3 V ) battery is connected between ( A ) and ( B ) The current supplied by the battery, if its positive terminal is connected to B is A ( .0 .15 ~ A ) в. 0.3 А ( c .3 A ) D. 1.4 |
12 |

788 | Among the following one can act as the building blocks for the other gates is A. NAND and NOR B. NAND and AND c. xor and or D. NOT and OR |
12 |

789 | The band gaps of an insulator, conductor and semi conductor are respectively ( boldsymbol{E}_{boldsymbol{g} 1}, boldsymbol{E}_{boldsymbol{g} mathbf{2}} ) and ( boldsymbol{E}_{boldsymbol{g} mathbf{3}} . ) The relationship between them is given as A ( . E_{g 1}>E_{g 2}E_{g 2}>E_{g 3} ) C ( . E_{g 1}E_{g 3} ) D. ( E_{g 1}<E_{g 2}<E_{g 3} ) |
12 |

790 | How many electrons are there is the outermost shell of silicon atom? |
12 |

791 | To which logic gate does the truth table given below correspond? ( begin{array}{ccc}mathbf{A} & mathbf{B} & mathbf{Y} \ 0 & 0 & 1 \ 1 & 0 & 1 \ 0 & 1 & 1 \ 1 & 1 & 0end{array} ) A. OR gate B. AND gate c. NAND gate D. NOR gate |
12 |

792 | The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. The forbidden band energy for the semiconductor in ( e V ) is A . 0.5 B. 0.9 ( c .0 .7 ) D. 1. |
12 |

793 | A strip of copper and another of germanium are cooled from room temperature to ( 80 K ). The resistance of A. each of these decreases. B. copper strip decreases and that of germanium decreases C. copper strip decreases and that of germanium increases D. each of these increases. |
12 |

794 | Analyse the given circuit diagram of a half wave rectifier and answer the following questions. a.Identify the components labelled as ( M ) and ( N ) What are the changes to be made in the following components for the converting this to a full wave rectifier I. Transformer ii. No.of Dioder iii. Draw the output form of a fill rectifier. |
12 |

795 | When the source voltage increases in a zener regulator, which of these currents remains approximately constant? A. Series current B. zener current c. Load current D. Total current |
12 |

796 | Symbolic representation of photodiode is- ( A ) B. ( c ) ( D ) |
12 |

797 | Silicon nitride has band gap energy of ( e v ) |
12 |

798 | Distinguish between n type and p type semi conductors. |
12 |

799 | State whether given statement is True or False
The depletion layer in the p-njunction region is caused by diffusion of carriers. |
12 |

800 | State the properties and uses of a Junction transistor |
12 |

801 | Zener diode is used for A. amplification B. rectification C. stabilisation D. all of the above |
12 |

802 | Assume that the number of hole- electron pair in an intrinsic semiconductor is proportional to ( e^{Delta E / 2 k T} . ) Here ( Delta E= ) energy gap and ( boldsymbol{k}=mathbf{8 . 6 2} times mathbf{1 0}^{mathbf{5}} boldsymbol{e V} / boldsymbol{K} . ) The energy gap for silicon is ( 1.1 e V . ) The ratio of electron hole pairs at ( 300 K ) and ( 400 K ) is ( mathbf{A} cdot e^{5.104 times 10^{-8}} ) B ( cdot e^{-5} ) ( c cdot c ) D. ( e^{2} ) |
12 |

803 | A hole is: A. a positively charged electron B. an electron in valence band c. an unfilled covalent bond D. an excess electron in covalent bond |
12 |

804 | When a forward bias is applied to ( mathrm{p}-mathrm{n} ) junction it: A. Raises the potential barrier. B. Reduces the majority carrier current to zero. c. Lowers the potential barrier. D. None of the above |
12 |

805 | 50. How many NAND gate are used to form AND gate? (a) 1 (b) 2 (c) 3 (d) 4 |
12 |

806 | 42. In question 38, the change in output across load is (a) 5 V (b) 10 V (c) 15 V (d) 16 V |
12 |

807 | Explain the use of N-P-N Transistor as an amplifier in common emitter mode under the following heads. (i) Labelled circuit diagram. (ii) Working. |
12 |

808 | If the forward voltage in a semiconductor diode is changed from ( 0.5 V ) to ( 0.7 V, ) then the forward current changes by ( 1.0 m A . ) The forward resistance of diode junction will be ( mathbf{A} cdot 100 Omega ) в. ( 120 Omega ) c. ( 200 Omega ) D. 240Omega |
12 |

809 | When the band gap for a semiconductor is low A. conductivity of that material is low B. conductivity of that material is highh c. the resistance of that material is highh D. none of the above |
12 |

810 | In which of the configurations of a transistor, the power gain is highest? A. Common base B. Common emitter c. common collector D. Same in all the three |
12 |

811 | If the resistivity of an alloy is ( rho^{prime} ) and that of constituent metal is ( rho ) then : A ( cdot rho^{prime}>rho ) B . ( rho^{prime}<rho ) C ( cdot rho^{prime}=rho ) D. there is no simple reaction between ( rho^{prime} & rho ) |
12 |

812 | In an n-p-n transistor circuit, the collector current is ( 9 mathrm{mA} ). If ( 90 % ) of the electrons emitted reach the collector. Then the emitter current is ( A cdot 8.1 mathrm{mA} ) B. 8 mA ( c cdot 9 m A ) D. ( 10 mathrm{mA} ) |
12 |

813 | 4. A pure semiconductor has equal electron and hole concentration of 100m-. Doping by indium increases nn to 4.5 x 1022 m². What is n in the doped semiconductor? (a) 100 m- (b) 1022 m- (d) 4.5 x 1022 m- 1032 (c) 4.5×1022 m3 |
12 |

814 | Avalanche breakdown is primarily dependent on the phenomenon of : A . Collision B. Ionisation c. Doping D. Recombination |
12 |

815 | The value of ( overline{1}+overline{1} ) is ( A cdot 2 ) B. 0 ( c .1 ) D. 10 |
12 |

816 | E. Negative temperature A. Hole ( quad ) coefficient of resistance B. Copper F. Energy vacancy G. Positive temperature coefficient C. Doping ( quad ) of resistance H. Addition of impurity to increase D. ( quad ) the conductivity Germanium Charges are holes and electrons Match the above lists: ( A cdot A-H, I B-E C-F D-G ) B. A-E B-F,I C-G D-H C ( . ) A-F B-G C-H D-E, D. A-G,I B-H C-E D-F |
12 |

817 | In a semiconductor A. There are no free electrons at any temperature B. The number of free electrons is more than in a conductor C. There is no free electrons at OK D. None of these |
12 |

818 | What are semiconductors? Give examples. |
12 |

819 | A ( p ) -type semiconductor has acceptor levels 57 me ( V ) above the valance band. The maximum wavelength of light required to create a hole is (Planck’s constant ( left.h=6.6 times 10^{-34} J-sright) ) A ( .57 AA ) В. ( 57 times 10^{-3} dot{A} ) c. 217100 月 D . ( 11.61 times 10^{-33} dot{A} ) |
12 |

820 | For a P-Njunction diode. A. Forward current in ( mathrm{mA} ) and reverse current is in ( mu A ) B. Forward current is in ( mu A ) are reverse current is in ( mathrm{mA} ) C. Both forward and reverse currents are in ( mu A ) D. Both forward and reverse currents are in ( mathrm{mA} ) E. No current flows in any direction |
12 |

821 | What is the order of magnitude of the resistance of a dry human body? A . ( 10 Omega ) B . ( 10^{4} Omega ) c. 10 МOmega D. ( 10 mu Omega ) |
12 |

822 | The typical operating current for a lightemitting diode is approximately: A .1 to ( 5 m A ) B. 5 to ( 20 m A ) c. 20 to ( 500 m A ) D. 500 to ( 2000 m A ) |
12 |

823 | The colour of light emitted by an LED depends on A. Its reverse bias B. The amount of forward current c. Its forward bias D. Type of semiconductor material |
12 |

824 | Which one is the weakest type of bonding in solids? A. Ionic B. Covalent c. Metallic D. vander wall’s |
12 |

825 | Thermistor material is pressed A. under zero pressure B. under low pressure c. under high pressure D. under low volume |
12 |

826 | If the bandgap between valence band and conduction band in a material is 0 ( e V ), then the material is A. Semiconductor B. Good conductor c. superconductor D. Insulator |
12 |

827 | (a) Describe briefly, with the help of a diagram, the role of the two important processes involved in the formation of a ( p-n ) junction (b) Name the device which is used as a voltage regulator. Draw the necessary circuit diagram and explain its working. |
12 |

828 | Doping of intrinsic semiconductor is done A. To neutralize charge carriers B. To increase the concentration of majority charge carriers C. To make it neutral before disposal D. To carry out further purification |
12 |

829 | Why does the thickness of depletion layer of pn-junction increases in reverse biasing ?Draw the circuit diagram of reverse biasing. | 12 |

830 | The immpurity atoms with which pure silicon should be doped to make a ( mathrm{p} ) type semiconductor are those This question has multiple correct options A. Boron B. Aluminium c. Phosphorus D. Antimony |
12 |

831 | What does LED stand for? A. Light emitting display B. Light energy display C. Light emitting diode D. Light emitting detector |
12 |

832 | 46. Which gate is represented by this figure? (a) NAND gate (b) AND gate (c) NOT gate (d) OR gate |
12 |

833 | Light of wavelength ( 6000 mathrm{nm} ) falls on a p-njunction photodiode. This photodiode is fabricated from a semiconductor with a band gap of 2.8 eV. Then, which of the following statement is true? A. This wavelength is not detected by the photodode B. This wavelength is detected by the photodiode c. Light is reflected back completely D. None of the above |
12 |

834 | Which of the following statement(s) is/are correct This question has multiple correct options A. If the band gap becomes much more higher for a semiconductor then electrons from lower energy state can’t move to higher energy state B. Lesser the band gap lesser is the conduction C. Lesser the band gap higher is the conduction D. none of the above |
12 |

835 | 62. With reference to the figure which of the following is possible? (a) A = 0, B = 0, X = 1 (c) A = 0, B = 0, X = 0 (b) A = 0, B = 1,X=0 (d) A = 1, B = 1,X=0 |
12 |

836 | The order of size of an IC is: ( mathbf{A} cdot 10^{-3}-10^{-1} m ) B ( cdot 10^{1}-10^{3} m ) C ( cdot 10^{-1}-10^{1} m ) D. ( 10^{-9}-10^{-6} m ) |
12 |

837 | How many minimum NAND GATEs are required for obtaining an output of ( A . B+C . D ? ) |
12 |

838 | The part of a trasistor which is heavily doped to produce large number of majority carriers is : A . emitter B. base c. collector D. can be any of the above three |
12 |

839 | Assume that each diode as shown in the figure has a forward bias resistance of ( 50 Omega ) and an infinite reverse bias resistance. The current through the resistance ( 150 Omega ) is: A ( .0 .66 A ) B. ( 0.05 A ) c. zero D. ( 0.04 A ) |
12 |

840 | The diffusion current in a p-njunction is greater than the drift current when the junction is A. forward biased. B. reverse biased c. unbiased. D. both forward and reverse biased |
12 |

841 | In p-type semiconductor major current carriers are: A. negative ions B. holes c. electrons D. all of these |
12 |

842 | Which one of the following diagrams correctly represents the energy levels in the p-type semiconductor? ( A ) в. Band gap ( c ) band D. Conduction band |
12 |

843 | Wavelength of a laser beam can be used as a standard of: A. time B. temperature c. angle D. length |
12 |

844 | 33. The current gain for a transistor used in common-emitte configuration is 98. If the load resistance is 1 MS and the internal resistance is 60 S2, what is the voltage gain (a) 90 (b) 95 (c) 100 (d) None of the above |
12 |

845 | Explain the working of a diode as half wave rectifier. | 12 |

846 | The bond, that exists in a semiconductor is A. covalent bond B. ionic bond c. metalic bond D. hydrogen bond |
12 |

847 | For filtering low frequency noise out of a signal the circuit can be built by just putting resistor and capacitor in A. Series B. Parallel c. Perpendicular D. Bipolar |
12 |

848 | Which of the following is an example of a direct band gap intrinsic semiconductor? A. Silicon B. Germanium c. Gallium Arsenide D. none of these |
12 |

849 | The width of the depleted region of a p-n junction is of the order of a few tenth of ( mathbf{a} ) A. millimeter B. micrometer c. metre D. nanometre |
12 |

850 | For silicon, the energy gap at ( 300 K ) is ( mathbf{A} cdot 1.1 W ) в. ( 1.1 J ) c. ( 1.1 e V ) D. None of these |
12 |

851 | In the diagram shown below, the input is across the terminals ( A ) and ( C ) and the output is across ( B ) and ( D ) Then the output is A. Zero B. Same as input c. Full wave rectified D. Half wave rectified |
12 |

852 | toppr 5 Q Type your question ( B ) ( c ) ( D ) |
12 |

853 | Assertion Semiconductors are solids with conductivities in the intermediate range from ( 10^{-6}-10^{4} ) ohm ( ^{-1} m^{-1} ) Reason Intermediate conductivity in semiconductor is due to partially filled valence band. 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 |

854 | A Zener diode when used as a voltage regulator, is connected (a) in forward bias. (b) in reverse bias. (c) in parallel to the load. (d) in series to the load. A. (a) and (b) are correct B. (b) and (c) are correct c. (a) only is correct D. (d) only is correct |
12 |

855 | With the help of a diagram, show how you can use several NAND gates to obtain an OR gate. |
12 |

856 | Which of the following statement(s) is/are correct: A. The gap between the top of the valance band and the bottom of the conduction band is called energy band ( operatorname{gap} ) B. More band gap results in less electron transfer c. A semiconductor is a material with a small but nonzero band gap that behaves as an insulator at absolute zero D. All of the above |
12 |

857 | 51. Sum of the two binary numbers (1000010), and (11011), is (a) (111101)2 (b) (111111)2 (c) (101111)2 (d) (111001), |
12 |

858 | 1. A 2 V battery is connected across the points A and B as shown in the figure given 102 below. Assuming that the resistance of each diode is 102 zero in forward bias and infinity in reverse bias, the current supplied by the battery when its positive AB terminal is connected to A is (a) 0.2 A (b) 0.4 A (c) Zero (d) 0.1 A |
12 |

859 | Draw the typical input and output characteristic of an ( n-p-n ) transistor in ( C E ) configuration. Show how these characteristics can be used to determine (a) the input resistance ( left(r_{i}right), ) and (b) current amplification factor ( (boldsymbol{beta}) ) |
12 |

860 | Alternating current is converted to direct current by A . rectifier B. dynamo c. transformer D. motor |
12 |

861 | Electric conduction in a semiconductor takes place due to A. electrons only B. holes only c. both electrons and holes D. neither electrons nor holes |
12 |

862 | In graphs of the electronic band structure of solids, the band gap generally refers to the between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. A. current difference B. energy difference (in electron volts) c. hole difference D. none of the above |
12 |

863 | Plot a graph showing variation of current versus voltage for the material Ga. |
12 |

864 | The voltage gain of the following amplifier is A . 10 B. 100 c. 1000 D. 9.9 |
12 |

865 | State whether given statement is True or False The resistance of intrinsic semiconductors increase with increase in temperature A. True B. False |
12 |

866 | Draw a circuit diagram of a transistor amplifier in CE configuration Define the terms: (i) Input resistance and (ii) Current amplification factor. How are these determined using typical input and output characteristics? |
12 |

867 | A storage battery takes ( t_{0} ) time when DC current ( I_{0} ) is used to charge it. Find the time taken if a half wave rectifier is used with ( A C ) mains and effective current is ( boldsymbol{I}_{0} ) A ( cdot t_{0} pi ) в. ( frac{2 t_{0}}{pi} ) c. ( frac{pi t_{0}}{2} ) D. ( t ) |
12 |

868 | If in a p-njunction diode, a square input signal of ( 10 V ) is applied as shownThen the output signal across ( R_{L} ) will be ( A ) в. ( c ) D. |
12 |

869 | If ( V_{A} ) and ( V_{B} ) denote the potentials of ( A ) and ( mathrm{B} ), then the equivalent resistance between ( A ) and ( B ) in the adjoint electric circuit is ( A cdot 10 Omega ) if ( V_{A}>V_{B} ) B. ( 5 Omega ) if ( V_{A}V_{B} ) D. ( 20 Omega ) if ( V_{A}>V_{B} ) |
12 |

870 | Energy band gap between valence band and conduction band for conductor is: A. more than semiconductors B. Zero c. more than insulators D. None of these |
12 |

871 | The output current versus time curve for a rectifies is shown in the figure. The average value of output current in this case is ( A ) в. ( frac{I_{0}}{2} ) c. ( frac{2 I_{0}}{pi} ) ( D cdot l_{0} ) |
12 |

872 | half – malf 8. The circuit shown in following figure contains two diode D, and D, each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6 V, the current through the 100 1502 ohms resistance (in amperes) is (a) Zero SO2 (b) 0.02 (c) 0.03 (d) 0.036 6 V (1) Acording to the given polarity diode is forward ng 1002 ite ca |
12 |

873 | NAND gate in the following is ( A ) в. ( c ) D. |
12 |

874 | (i) Distinguish between a conductor and a semi conductor on the basis of energy band diagram (ii) The following figure shows the input waveforms ( (A, B) ) and the output waveform (Y) of a gate. Identify the gate, write its truth table and draw its logic symbol. |
12 |

875 | In solar cells, a silicon solar cell ( (mu= ) 3.5) is coated with a thin film of silicon monoxide ( boldsymbol{S} boldsymbol{i} boldsymbol{O}(boldsymbol{mu}=mathbf{1 . 4 5}) ) to minimise reflective losses from the surface. Determine the minimum thickness of SiO that produces the least reflection at a wavelength of ( 550 n m, ) near the centre of the visible spectrum. |
12 |

876 | For a common emitter amplifier, the current gain is ( 70 . ) If the emitter current is ( 8.8 mathrm{mA} ), then the collector current is: ( mathbf{A} cdot 0.124 m A ) в. ( 4.34 m A ) ( c .8 .68 m A ) D. ( 1.72 m A ) |
12 |

877 | The impurity atoms with which pure silicon would be doped to make a p-type semiconductor are those of This question has multiple correct options A. Phosphorus B. Boron C. Antimony D. Aluminium |
12 |

878 | Which among the following is an example of a semiconductor? A. cuprous oxide B. iron c. copper D. aluminium |
12 |

879 | In n-type semiconductors, the electron concentration is equal to: A. density of donor atoms B. density of acceptor atoms C. density of both type of atoms D. neither density of acceptor atoms nor density of donor atoms |
12 |

880 | Identify the logic operation of the following logic circuit: A. NAND B. AND c. Non D. on |
12 |

881 | What will be the input of ( A ) and ( B ) for Boolean expression [ (overline{A+B})(overline{A cdot B})=1 ] A .0,0 в. 0,1 c. 1,0 D. ( 1, ) |
12 |

882 | In ( V ) -1 characteristic of a p-n junction, reverse biasing results in A. leakage current B. the current barrier across junction increases c. no flow of current D. large current |
12 |

883 | Assertion Diode lasers are used as optical sources in optical communication. Reason Diode lasers consume less energy. |
12 |

884 | Which among the following having highest band gap? A. Diamond B. Silicon c. Germanium D. Gallium nitride |
12 |

885 | The thickness of depletion layer is approximately A . ( 1 mu m ) B. ( 1 mathrm{mm} ) ( c cdot 1 c m ) D. ( 1 m ) |
12 |

886 | In the circuit diagram, the current through the Zener diode is : ( mathbf{A} cdot 10 m A ) B. ( 3.33 m A ) ( mathbf{c} cdot 6.67 m A ) ( mathbf{D} cdot 0 m A ) |
12 |

887 | In common emitter amplifier, the current gain is ( 62 . ) The collector resistance and input resistance are ( 5 k Omega ) an ( 500 Omega ) respectively. If the input voltage is ( 0.01 V, ) the output voltage is A. ( 0.62 V ) V B. ( 6.2 V ) ( c .62 V ) D. ( 620 V ) |
12 |

888 | The diagram of a logic circuit is given below, the output of the circuit is represented by ( A cdot W+(X+Y) ) B. ( w+(x . y) ) ( c . w .(x+y) ) D. w. (x.y) |
12 |

889 | ILLUSTRATION 31.3 In a p-n junction diode, the current I can (ev be expressed as, 1 = 1. ex where 1is called the (KBT reverse saturation current, Vis the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, kr is the Boltzmann constant (8.6 x 10eV/K) and T is the absolute temperature. If for a diode, 10 = 5 x 10-2 A and T = 300 K, then (a) what will be the forward current at a forward voltage of 0.6 V? (b) what will be the increase in the current if the voltage across the diode is increased to 0.7 V? (c) what is the dynamic resistance? (d) what will be the current if reverse bias voltage changes from 1 V to 2 V? |
12 |

890 | 6. A p-n junction diode when forward-biased has a drop of 0.5 V. We want to see 1.5 V battery to forward-bias the diode. What resistance must be connected in series with the diode so that the maximum current does not exceed 1 mA? (a) 10-32 (b) 100 22 (c) 10 2 (d) 10° 22 in |
12 |

891 | The conductivity of intrinsic semiconductor decreases with increase in temperature A. True B. False |
12 |

892 | In a common-base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor ( (boldsymbol{beta} ) will be A .49 B. 50 ( c cdot 51 ) D. 48 |
12 |

893 | Which of following gates produces output of ( 1 ? ) ( A ) B ( c ) ( D ) |
12 |

894 | A Zener diode, having breakdown voltage equal to ( 15 V ) is used in a voltage regulator circuit shown in figure. The current through the diode is ( A cdot 10 m A ) B. ( 15 m A ) ( c cdot 20 m A ) ( mathbf{D} cdot 5 m A ) |
12 |

895 | Across the depletion region, there is a barrier potential which A. prevents the movement of electron from the n region into the p region B. prevents the movement of electron from the p region into the n region C. prevents the movement of holes from the n region into the p region D. prevents the movement of holes from the p region into the n region |
12 |

896 | In N-type semiconductors, holes are: A. majority carriers B. minority carriers ( c . ) absent D. none of these |
12 |

897 | Which of the following has least band gap energy at ( 273 K ) A . Insb B. InAs ( c cdot ln P ) D. Gasb |
12 |

898 | Give two example of intrinsic semiconductor? A . aluminum B. Silicon, germanium c. copper D. nitrogen |
12 |

899 | toppr Q туре your question currents is ( frac{7}{4}, ) then what is the ratio of their drift velocities? (1) (2) (3) |
12 |

900 | In a ( p ) -type semiconductor germanium is doped with: A. Gallium B. Aluminium c. Boron D. All of the above. |
12 |

901 | The depletion region in a semiconductor diode is formed at the Junction. A. True B. False |
12 |

902 | When pure semimconductor is doped then its electrical conductivity A. increases B. decreases c. remains constant D. initially increases and then decreases |
12 |

903 | The following represent standrard symbols for transistors. ( (i) ) (i) A. both represent PNP transistors B. both represent NPN transistors C. (i) represents PNP transistor while (ii) represent the NPN transistor D. (i) represents NPN transistor while (ii) represent the PNP transistor |
12 |

904 | What is meant by forward bias and reverse bias of a diode? Indicate in a figure. |
12 |

905 | Let ( n_{p} ) and ( n_{e} ) be the number of holes and conduction electrons in an extrinsic semiconductor. Then A ( cdot n_{p}>n_{e} ) в. ( n_{p}=n_{e} ) c. ( n_{p}<n_{e} ) D ( cdot n_{p} neq n_{e} ) |
12 |

906 | 28. In case of NPN-transistors, the collector current is always less than the emitter current because (a) collector side is reverse biased and emitter side is forward biased (b) after electrons are lost in the base and only remaining ones reach the collector (c) collector side is forward biased and emitter side is reverse biased (d) collector being reverse biased attracts less electrons |
12 |

907 | Choose the correct statement: A. Integrated circuits are less efficient in performance at all voltages. B. Integrated circuits are more efficient in performance at low voltages. C. Integrated circuits are less efficient in performance at high voltages. D. Performance of an integrated circuit is independent of the magnitude of applied voltage. |
12 |

908 | Can we take one slab of p-type semiconductor and physicallyjoin it to another n-type semiconductor to get ( p-n ) junction? |
12 |

909 | If the rms value of sinusoidal input to a full wave rectifier is ( frac{v_{o}}{sqrt{2}}, ) then the rms value of the rectifier’s output is? A ( cdot frac{v_{o}}{sqrt{2}} ) B. ( frac{v_{o}^{2}}{sqrt{2}} ) c. ( frac{v_{o}^{2}}{2} ) D. ( sqrt{2} V_{o}^{2} ) E ( .2 V_{o}^{2} ) |
12 |

910 | A system of logic gates is shown in the figure. From the study of truth table it can be found that to produce a high output (1) at ( R, ) we must have в. ( X=1, Y=1 ) c. ( X=1, Y=0 ) D. ( X=0, Y=0 ) 0 |
12 |

911 | Given : A and B are input terminals. ( operatorname{Logic} 1=>5 V ) ( operatorname{Logic} mathbf{0}=<mathbf{1} boldsymbol{V} ) Which logic gate operation, the following circuit does? ( A ). AND Gate B. OR Gate c. XOR Gate D. NOR Gate |
12 |

912 | The diagram of a logic gate circuit is given below. The output ( Y ) of the circuit is represented by A ( . A cdot(B+C) ) B. ( A cdot(B cdot C) ) c. ( A+(B cdot C) ) ( mathbf{D} cdot A+(B+C) ) |
12 |

913 | The main cause of Zener breakdown is A. the base semiconductor being germanium. B. production of electron-hole pairs due to thermal excitation. C . low doping. D. high doping. |
12 |

914 | A Zener diode, having breakdown voltage equal to ( 15 V ), is used in a voltage regulator circuit shown in figure. The current through the diode is A . ( 10 mathrm{mA} ) в. ( 15 mathrm{mA} ) ( c .20 m A ) D. ( 5 m A ) |
12 |

915 | Zener diode works on A. zero bias B. reverse bias C. forward bias D. infinite bias |
12 |

916 | Symbols in (I) and (II) represent standard transistors. Then A. both represents p-n-p transistors B. both represents n-p-n transistors c. (I) represents n-p-n and (II) represents ( p ) -n-p. D. (I) represents p-n-p and (II) represents n-p-n- |
12 |

917 | Which of the following are correct for insulators? A. The valence band is partially filled with electrons. B. The conduction band is partially filled with electrons. C. The conduction band is partially filled with electrons and valence band is empty. D. The conduction band is empty and the valence band is filled with electrons. |
12 |

918 | From the circuit shown below, the maximum and minimum value of zener diode current are : ( mathbf{A} cdot 6 m A, 5 m A ) B. ( 14 mathrm{mA}, 5 mathrm{mA} ) ( mathbf{c} .9 m A, 1 m A ) D. ( 3 m A, 2 m A ) |
12 |

919 | In a n-type semiconductor, which of the following statement is true? A. Electrons are majority carriers and trivalent atoms are dopants B. Electron are minority carriers and pentavalent atoms are dopants. C. Holes are minority carriers and pentavalent atoms are dopants. D. Holes are majority carriers and trivalent atoms are dopants |
12 |

920 | Draw the diagram of a Helium-Neon laser tube and label the parts. | 12 |

921 | 64. The process of negative feedback in electronics can involve returning a fraction of the output of an operational amplifier to the input. This may affect the gain and the bandwidth (the range of frequency over which the gain is constant). Which one of the following combinations of effects is correct? Effect on gain Effect on bandwidth (a) Increased Decreased (b) Decreased Decreased (c) Increased Unchanged (d) Decreased Increased |
12 |

922 | Which of the following semi-conducting devices is used as voltage regulator? A. Zener diode B. LASER diode c. Photo diode D. Solar cell |
12 |

923 | Power gain for ( N-P-N ) transistor is ( 10^{6}, ) input resistance ( 100 Omega ) and output resistance ( 1000 Omega ). find out current gain. A. 100 в. 150 ( c cdot 200 ) D. 50 |
12 |

924 | In a semiconductor, the energy gap between valence band and conduction band is of the order of A . Mev B. kev ( c cdot e v ) D. Gev |
12 |

925 | 21. In a common emitter amplifier circuit using an n-D-n transistor, the phase difference between the input and the output voltages will be (a) 135° (b) 180° (d) 90° (JEE Main 2017) (C) 45° |
12 |

926 | Choose the correct statements: This question has multiple correct options A. It is easier to fabricate 10000 AND gates using circuit components than on an integrated chip. B. It is easier to fabricate 10000 AND gates on an integrated chip than fabricating them using circuit components. C. It is easier to fabricate a single AND gate using circuit components as compared to on an IC. D. It is easier to fabricate a single AND gate on an IC as compared to using circuit components. |
12 |

927 | Write down the truth table for the given logic circuit with Boolean expression |
12 |

928 | A p-n photodiode is made of a material with a band gap of ( 2.0 mathrm{eV} ). The minimum frequency of radiation that can be absorbed by the material is nearly: |
12 |

929 | In a transistor, the base is A. a conductor of low resistance B. a conductor of high resistance C. an insulator D. an extrinsic semiconductor |
12 |

930 | A pure semiconductor at absolute zero has A. Absence of electrons in the conduction band. B. All the electrons occupying the valence band. C . Large ( E_{g} ) value. D. All of the above. |
12 |

931 | The current gain in common base amplifier is A . high B. very low c. about 1 D. very high |
12 |

932 | Construct a AND gate using only NOR gates only | 12 |

933 | The battery connections required to forward bias a pnjunction are A. tve terminal to p and -ve terminal to ( n ) B. -ve terminal to p and +ve terminal to n c. – -ve terminal to p and-ve terminal to D. None of these |
12 |

934 | The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 248 nm is incident on it. The forbidden band energy for the semiconductor in ( e V ) is |
12 |

935 | Negative feed back A . increases stability B. decreases stability c. produces oscillation D. stops current in the tube |
12 |

936 | Applying forward bias in p-njunction, the potential barrier A. increases B. decreases c. remains unchanged D. becomes zero |
12 |

937 | Consider the junction diode as ideal The value of current flowing through ( A B ) is в. ( 10^{-2} A ) c. ( 10^{-1} A ) D. ( 10^{-3} A ) |
12 |

938 | If voltage across zener diode is ( 6 V ) then find out value of maximum resistance in this condition. ( A cdot 2 k Omega ) 3. ( 1 k Omega ) ( c .5 k Omega ) D. ( 4 k Omega ) |
12 |

939 | What are conductors and insulators? Give examples. |
12 |

940 | Among the following which one gives output 1 in the AND gate. A. ( A=0, B=0 ) в. ( A=1, B=1 ) c. ( A=1, B=0 ) D. ( A=0, B=1 ) |
12 |

941 | Identify the mismatched pair from the following A. zener diode : voltage regulator B. germanium doped with phosphorous : n-type semiconductor C. semiconductor: band gap > 3 eV D. p-n junction diode : rectifier E. silicon doped with aluminium : p-type semiconductor |
12 |

942 | A transistor is essentially A. a current operated device B. power driven device C . a voltage operated device D. resistance operated device |
12 |

943 | How many electrodes are there in PNP or NPN transistor? ( A cdot 3 ) B. ( c cdot 2 ) ( D ) |
12 |

944 | In the forward bias characteristic curve, a diode appears as: A. an OFF switch B. a high resistance c. an on switch D. a capacitor |
12 |

945 | In reverse bias, pn-junction diode depletion layer width: A. decreases B. increases c. remains same D. can’t predict |
12 |

946 | A circuit of logic gates given below, some input signal ( A, B, C ) are given with their output signal ( x, y ) and ( z ) is given in respective option, choose correct options: This question has multiple correct options |
12 |

947 | In the diagram, section A represents: ( C ) ( D ) A. N-type germanium B. P-type germanium C. Anode D. Diode |
12 |

948 | If the wavelength of light emitted when an electron fall from the first excited state to the ground state are ( lambda ), the wavelength of emitted radiation when an electron fall from meta-stable state to the ground state will be A. greater than ( lambda ) B. less than ( lambda ) ( c cdot lambda ) D. cannot be determined |
12 |

949 | Draw the circuit diagram of a full wave rectifier and state how it works. |
12 |

950 | Figure shows a diode connected to an external resistance and a battery. Assuming the barrier potential developed in the diode to be ( 0.5 mathrm{V} ), find the value of current in the circuit in ( mathrm{mA} ) |
12 |

951 | Diode 11. A sinusoidal voltage of rms value 200 V is connected to the diode and capacitor ) RMS © 200 Volt C in the circuit shown so that half-wave rectification occurs. The final potential difference in volt, across C, is (a) 500 (b) 200 (c) 283 (d) 141 m |
12 |

952 | With the help of necessary circuit diagram, explain the working of a photodiode used for detecting optical signals. | 12 |

953 | The band structure determines the behaviour of a solid A. chemical B. electrical c. mechanical D. molecular |
12 |

954 | How does the energy gap of an intrinsic semiconductor vary, when doped with a trivalent impurity? | 12 |

955 | Write any three distinctions between ( p ) type and n-type semiconductor | 12 |

956 | The energy band diagrams for three semiconductor sample of silicon are shown. It follows that. A. Sample X is undoped while samples Y and Z have been doped with a third group and a fifth group impurity respectively B. Sample X is undoped while both samples Y and Z have been doped with a fifth group impurity c. Sample X has been doped with equal amounts of third and fifth group impurities while samples ( Y ) and ( z ) are undoped D. Sample X is undoped while samples Y and Z have been doped with a fifth group and a third group impurity respectively |
12 |

957 | The energy bands are present only when the substance is present in the solid state. A. True B. False |
12 |

958 | What are Intrinsic and Extrinsic semi- conductors? |
12 |

959 | Integrated circuit is defined as: A. a single electronic circuit on a small plate of semiconductor material. B. a set of electronic circuits on one small plate of semiconductor material. C . a circuit capable of generating dc currents. D. a plate of semiconductor material used to connect external multiple circuits |
12 |

960 | Which of the following represents NAND gate? ( A ) B. ( c ) ( D ) |
12 |

961 | A transistor has ( alpha=0.95 . ) If the emitter current is ( 10 m A ), then the collector current will be A . ( 9.5 mathrm{mA} ) в. ( 10 mathrm{mA} ) c. ( 0.95 mathrm{mA} ) D. ( 95 mathrm{mA} ) |
12 |

962 | An intrinsic semiconductor at the absolute zero temperature A. behaves like a metallic conductor B. behaves like an insulator c. has a large number of holes D. has a large number of electrons |
12 |

963 | The electron density of intrinsic semiconductor at room temperature is ( 10^{16} m^{-3} . ) When doped with a trivalent impurity, the electron density is decreased to ( 10^{14} m^{-3} ) at the same temperature. The majority carrier density is: A ( cdot 10^{16} m^{-3} ) В. ( 10^{18} m^{-3} ) ( mathbf{c} cdot 10^{21} m^{-3} ) D. ( 10^{20} mathrm{m}^{-3} ) E ( .10^{19} m^{3} ) |
12 |

964 | State whether given statement is True or False
Resistivity of semiconductor depends on atomic nature of semiconductor. |
12 |

965 | Draw the circuit arrangement for studying the ( V_{I} ) characteristics of a p-n junction diode in reserve bias. Plot the ( V-I ) characteristics in this case. |
12 |

966 | A semiconductor has equal number of electron and hole concentration of ( 2 times ) ( 10^{8} m^{-3} . ) On doping with a certain impurity, the electron concentration increases to ( 4 times 10^{10} m^{-3} ), then the new hole concentration of the semiconductor is A ( cdot 10^{6} m^{-3} ) B. ( 10^{8} m^{-3} ) c. ( 10^{10} m^{-3} ) D. ( 10^{12} m^{-3} ) |
12 |

967 | A transistor has ( alpha=0.95 . ) If the emitter current is ( 10 mathrm{m} A ), the base current will be A. ( 0.1 mathrm{mA} ) в. ( 0.2 mathrm{mA} ) ( c .0 .3 m A ) D. ( 0.5 mathrm{mA} ) |
12 |

968 | Holes are charge carriers in This question has multiple correct options A. intrinsic semiconductors B. ionic solids C. p-type semiconductors D. metals |
12 |

969 | Filter circuit A. eliminates a.c. component B. eliminates d.c. component c. does not eliminate a.c. component D. None of these |
12 |

970 | Assuming that the two diodes ( D_{1} ) and ( D_{2} ) used in the electric circuit shown in the figure are ideal, find out the value of the current flowing through ( 1 Omega ) resistor |
12 |

971 | In the half wave rectifier circuit operating from 50 ( boldsymbol{H} boldsymbol{z} ) mains frequency, the fundamental frequency in the ripple would be ( mathbf{A} cdot 2.5 H z ) B. ( 50 mathrm{Hz} ) c. ( 70.7 H z ) D. ( 100 H z ) |
12 |

972 | Explain using circuit diagram the working of ( n ) -p-n transistor as ( mathrm{CE} ) amplifier. Hence obtain expression for its voltage gain in common emitter configuration. |
12 |

973 | Diffusion current in a p-njunction is greater than the drift current in magnitude A. if the junction is forward-biased B. if the junction is reverse-biased c. if the junction is unbiased D. in no case |
12 |

974 | In a forward-biased photo-diode with increase in incident light intensity, the diode current: A . increases B. remains constant c. decreases D. none of the above |
12 |

975 | 15. The logic circuit below has the input waveforms A and B as shown. Pick out the correct output waveform. Y Input AG Input B- (a) ITAL () – ©_4A HUF (AIEEE 2009) |
12 |

976 | Write the truth table for a NAND gate connected as given in Figure. |
12 |

977 | The free electron density is more in A. Conductors B. Insulators c. Semi conductors D. Electrolytes |
12 |

978 | An LED operates under which biasing condition? A. Forward bias B. Reverse bias c. can operate both in forward and reverse bias D. No biasing is required |
12 |

979 | Conventional flow of current will always be from – A. p type ( rightarrow ) n type B. n type ( rightarrow ) p type c. ( n ) Type ( rightarrow ) n type D. None of these |
12 |

980 | A full wave rectifier circuit along with the input and output are shown in the figure. The contribution from the diode ( mathbf{1} ) is are A. ( C ) в. ( A, C ) ( c cdot B & D ) D. ( A, B, C, D ) |
12 |

981 | 13. Let np and n, be the number of holes and conduction electrons, respectively, in a semiconductor. Then (a) np>n in an intrinsic semiconductor (b) np = n, in an extrinsic semiconductor (c) np = n, in an intrinsic semiconductor (d) n. > np in an intrinsic semiconductor |
12 |

982 | In a n-p-n transistor, the collector current is ( 10 mathrm{mA} ). If ( 10 % ) of the electrons are lost in the base, then the emitter current is: A . ( 10 mathrm{mA} ) B. ( 0.9 mathrm{mA} ) c. ( 0.09 mathrm{mA} ) D. ( 11.1 mathrm{m} ) |
12 |

983 | (a) Draw the circuit diagram for studying the characteristics of a transistor in common emitter configuration. Explain briefly and show how input and output characteristics are drawn. (b) The figure shows input waveform ( A ) and ( mathrm{B} ) to a logic. Draw the output waveform for an OR gate. Write the truth table for this logic gate and draw its logic symbol. |
12 |

984 | What is a rectifier? With the help of a neat circuit diagram explain the working of a full wave rectifier. | 12 |

985 | characteristic for a semiconductor device. Which of the following statement is correct? A. It is V-I characteristic for solar cell where, point represents open circuit voltage and point B short circuit current B. It is for a solar cell and points A and B represent open circuit voltage and current, respectively C. It is for a photodiode and points ( A ) and ( B ) represent open circuit voltage and current respectively D. It is for a LED and points A and B represent open circuit voltage and short circuit current, respectively |
12 |

986 | Phosphorus which is used as an impurity to produce an extrinsic semiconductor is a ( _{-}- ) – impurity. A. Trivalent B. Divalent c. Tetravalent D. Pentavalent |
12 |

987 | Write the full name of LED. | 12 |

988 | Distinguish between ‘intrinsic’ and extrinsic’ semiconductors. |
12 |

989 | Two identical p-njunctions may be connected in series with battery in three ways as shown in the adjoining figure. The potential drop across the p-n junctions are equal in A. Circuit 1 and circuit 3 B. Circuit 1 and circuit 2 c. circuit 2 and circuit 3 D. circuit 2 only |
12 |

990 | The change in output voltage is approximately: ( mathbf{A} cdot 0.8 mu V ) в. ( 2 m V ) ( mathrm{c} .3 .2 mathrm{V} ) ( mathbf{D} cdot 80 mu V ) |
12 |

991 | Assertion NAND is a universal gate. Reason It can be used to describe all other logic gates. 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 |

992 | Three amplifier stages each with a gain of 10 are cascaded. The overall gain is A . 10 B. 30 ( c .1000 ) D. 100 |
12 |

993 | Consider the following statements A and ( mathrm{B} ) and identify the correct answer. Statement(A):A Zener diode is always connected in reverse bias to use it as voltage Statement(B):The potential barrier of a p-njunction lies between 0.1 to ( 0.3 V ) approximately. A. A and B are correct B. A and B are wrong c. A is correct but B is wrong. D. A is wrong but B is correct. |
12 |

994 | The forbidden energy band gap in conductors |
12 |

995 | An incandescent lamp is operated at ( 240 V ) and the current is ( 0.5 A . ) What is the resistance of the lamp? |
12 |

996 | The circuit shown given contains two ideal diodes, each with a forward resistance of ( 50 Omega ). If the battery voltage is ( 6 mathrm{V} ), the current through the ( 100 Omega ) resistance (in Amperes) is? A .0 .027 В. 0.020 ( c .0 .030 ) D. 0.036 |
12 |

997 | A logic gate which has an output’ ( 1^{prime} ) only when the inputs are complement to each other is. A. AND B. NAND c. Nor D. EXOR |
12 |

998 | What is Solar Panel? Write its main three uses. |
12 |

999 | Two constant parallel forces act on a wheel provided in a transistor for tunning as shown in the figure. If the wheel rotates then the work done per rotation will be A. 0.05 joule B. 0.0015 joule c. 0.031 joule D. 0.062 joule |
12 |

1000 | A semiconductor at ( 0 K ) behaves as : A. conductor B. insulator c. super conductor D. extensive semiconductor |
12 |

1001 | Which of the following is a characteristic of analog ICs? A. They can be used for analog input and output signals only. B. They cannot be used for analog input and output signals C. Input signal is analog but output signal is digital. D. Output signal is analog but input signal is digital. |
12 |

1002 | A transistor is operated in common- emitter configuration at ( V_{C}=2 V ) such that a change in the base current from ( 100 mu A ) to ( 200 mu A ) produces a change in the collector current from ( 5 mathrm{mA} ) to 10 mA. The current gain is : A . 50 B. 75 ( c cdot 100 ) D. 150 |
12 |

1003 | For a transistor, ( alpha_{d c} ) and ( beta_{d c} ) are the current ratios, then the value of ( frac{beta_{d c}-alpha_{d c}}{alpha_{d c} cdot beta_{d c}} ) is A . 1 в. 1.5 ( c cdot 2 ) D. 2.5 |
12 |

1004 | The given truth table is for ( begin{array}{lll}text { Input } & text { Input } & text { Output } \ mathrm{A} & mathrm{B} & mathrm{Y} \ 0 & 0 & 1 \ 0 & 1 & 1 \ 1 & 0 & 1 \ 1 & 1 & 0end{array} ) A. AND gate B. OR gate C. NAND gate D. NOR gate |
12 |

1005 | Which of the following statements is true for a p-n-p transistor when used in an amplifier circuit? A. Emitter is connected to negative terminal of a battery B. Base current is always lower than emitter current c. collector is connected to positive terminal of a battery D. collector current is always more than the emitter current |
12 |

1006 | In half-wave rectification, what is the output frequency if the input frequency is ( 50 H z ) What is the output frequency of a fullwave rectifier for the same input |
12 |

1007 | In the figure shown which one is correct diagram for LED? (b) (c) da ( A cdot b ) B. ( c ) D. |
12 |

1008 | When an external voltage ( V ) is applied across a semiconductor diode such that ( p- ) side is connected to the positive terminal of the battery and ( n- ) side to the negative terminal, it is said to be ( A ). reverse biased. B. forward biased c. bias free. D. None of these |
12 |

1009 | A Ge specimen is doped with Al. The concentration of acceptor atom is ( sim ) ( 10^{21} ) atoms ( / m^{3} . ) Given that the intrinsic concentration of electron hole pairs is ( sim 10^{19} / m^{3} . ) The concentration of electrons in the specimen is?? ( mathbf{A} cdot 10^{17} / m^{3} ) B . ( 10^{15} / m^{3} ) c. ( 10^{4} / m^{3} ) D. ( 10^{2} / m^{3} ) |
12 |

1010 | Write the logic symbol and truth table of NAND gate. | 12 |

1011 | A p-type semiconductor is made from a silicon specimen by doping on a average one indium atom per ( 5 times 10^{7} ) silicon atoms. If the number density of atoms in the silicon specimen is ( 5 times ) ( 10^{26} ) atoms ( / m^{3}, ) then the number of acceptor atoms in silicon per cubic centimeter will be: A ( .2 .5 times 10^{30} ) В. ( 1.0 times 10^{13} ) c. ( 1.0 times 10^{15} ) D. ( 2.5 times 10^{36} ) |
12 |

1012 | Select one donor impurity among the following: Boron ( (B), ) Aluminium ( (A l), ) and Arsenic ( (A s) ) |
12 |

1013 | Explain avalanche breakdown in a diode and zener breakdown in a zener diode | 12 |

1014 | Assertion A transistor amplifier in common emitter configuration has a low input impedance. Reason The base to emitter region is forward biased. A. Assertion is true, Reason is true; Reason is a correct explanation for Assertion B. Assertion is true, Reason is true; Reason is not a correct explanation for Assertion c. Assertion is true, Reason is false D. Assertion is false, Reason is true |
12 |

1015 | Assertion An AND gate is a universal gate. Reason The boolean expression for AND gate is ( A cdot B=C ) 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 |

1016 | Application of a forward bias to a ( mathrm{p}-mathrm{n} ) junction A. widens the depletion zone B. increases the potential difference across the depletion zone C. increases the number of donors on the n side D. increases the electric field in the depletion zone. |
12 |

1017 | Which of the statements given is true for p-type semiconductors (a) Electrons are majority carriers and trivalent atoms are the dopants. (b) Electrons are minority carriers and pentavalent atoms are the dopants. (c) Holes are minority carriers and pentavalent atoms are the dopants. (d) Holes are majority carriers and trivalent atoms are the dopants. |
12 |

1018 | An n-type semiconductor is A. Neutral B. Positively charged C . Negatively charged D. Negatively or positively charged depending on the amount of impurity added |
12 |

1019 | The intrinsic charge carrier density in germanium crystal at ( 300 K i s 2.5 times ) ( 10^{13} / mathrm{cm}^{3} . ) density in an n-type germanium crystal at ( 300 mathrm{K} ) be ( 5 times ) ( 10^{16} / c m^{3}, ) the hole density in this n-type crystal at ( 300 mathrm{K} ) would be A ( cdot 2.5 times 10^{13} / mathrm{cm}^{3} ) В. ( 5 times 10^{6} / c m^{3} ) c ( cdot 1.25 times 10^{10} / mathrm{cm}^{3} ) D. ( 0.2 times 10^{4} / c m^{3} ) |
12 |

1020 | For common emitter configuration of a transistor, the collector voltage ( V_{c}= ) ( 2 V ) and, base current changes from ( 100 mu A t o 200 mu A, ) and collector current changes from ( 5 mathrm{mA} ) to ( 10 mathrm{mA} ) The current gain is A . 100 B. 25 ( c cdot 125 ) D. 50 |
12 |

1021 | Assertion The number of electrons in a p-type silicon semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature Reason It is due to law of mass action. 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 |

1022 | The following one represents logic addition is A. ( 1+1=2 ) B. ( 1+1=10 ) c. ( 1+1=1 ) D. ( 1+1=11 ) |
12 |

1023 | A A ratery is cumectuatuss AD as shown in the figure. The value of the current supplied by the battery when in one case, battery’s positive terminal is connected to A and in other case when positive terminal of battery is connected to B will respectively be в. ( 0.1 A ) and ( 0.2 A ) c. 0.2 A and 0.4 A D. ( 0.4 mathrm{A} ) and ( 0.2 mathrm{A} ) |
12 |

1024 | The circuit has two oppositely connected ideal diodes in parallel. The current flowing in the circuit is A . ( 1.71 A ) B. ( 2.00 A ) c. ( 2.31 A ) D. ( 1.33 A ) |
12 |

1025 | Consider a p-njunction as a capacitor, formed with ( p ) and ( n ) material acting as thin metal electrodes and depletion layer width acting as separation between them. Based on this, assume that an n-p-n transistor is working as a amplifier in CE configuration. If ( C_{1} ) and ( C_{2} ) be base- emitter and collector-emitter junction capacitances, then A ( cdot C_{1}>C_{2} ) B. ( C_{1}<C_{2} ) ( mathbf{c} cdot C_{1}=C_{2} ) ( mathbf{D} cdot C_{1}=C_{2}=0 ) |
12 |

1026 | The bond in semiconductors is : A. covalent B. ionic c. metallic D. hydrogen |
12 |

1027 | Q Type your question ( mathbf{A} ) ( B ) ( mathbf{c} ) D. |
12 |

1028 | Show on a graph, the variation of resistivity with temperature for a typical semiconductor. |
12 |

1029 | The given circuit has two ideal diodes connected as shown in the figure below The current flowing through the resistance ( boldsymbol{R}_{mathbf{1}} ) will be A ( .3 .13 A ) B . ( 2.5 A ) c. ( 10.0 A ) D. ( 1.43 A ) |
12 |

1030 | When the input of a two input logic gate are 0 and ( 0, ) the output is ( 1 . ) When the inputs are 1 and 0 , the output is zero. The type of logic gate is A. xor B. NAND c. NOR D. or |
12 |

1031 | The arrangement shown in the figure performs the logic function of A. AND gate B. NAND gate c. or gate D. XOR gate |
12 |

1032 | The circuit given below represents which of the logical operations? ( A cdot A N D ) в. NOT ( c . ) ов D. NOR |
12 |

1033 | Explain with a neat diagram, how a p-n junction diode is used as a half wave rectifier. | 12 |

1034 | The electrical circuit used to get smooth D.C output from a rectifier circuit is called: ( mathbf{A} ). Filter B. Oscillator c. ( operatorname{cogic} ) gates D. Amplifier |
12 |

1035 | When a p-njunction diode is reverse biased A. electrons and holes are attracted towards each other and move towards the depletion region B. electrons and hole move away from the junction depletion region. C. height of the potential barrier decreases. D. no change in the current takes place. |
12 |

1036 | How can electrical conductivity of metals, insulator and semiconductors be explained qualitatively? |
12 |

1037 | The input of ( A ) and ( B ) for the Boolean expression ( (overline{boldsymbol{A}+boldsymbol{B}}) cdot(overline{boldsymbol{A} cdot boldsymbol{B}})=mathbf{1} ) is A . 0,0 в. 0,1 ( c .1,0 ) D. 1,1 |
12 |

1038 | The value of the resistor, ( boldsymbol{R}_{S}, ) needed in the DC voltage regulator circuit shown here, equals A ( cdot frac{left(V_{i}+V_{L}right)}{(n+1) I_{L}} ) B. ( frac{left(V_{i}-V_{L}right)}{n I_{L}} ) c. ( frac{left(V_{i}+V_{L}right)}{n I_{L}} ) D. ( frac{left(V_{i}-V_{L}right)}{(n+1) I_{L}} ) |
12 |

1039 | Which of the following is/ are correct concerning “The working principle of LED”? This question has multiple correct options A. electrons travel from the n-type to the p-type and holes in the opposite direction B. n-type silicon has extra electrons to combine with the extra holes of p-type silicon C. p-type silicon has extra electrons to combine with the extra holes of n-type silicon D. Both A and C |
12 |

1040 | The value indicated by Fermi energy level in an intrinsic semiconductor is A. the average energy of electrons and holes. B. the energy of electrons in conduction band C. the energy of holes in valence band D. the energy of forbidden region |
12 |

1041 | A thermistor: A. Is a thermally sensitive resistor B. Is made of a semiconductor C. Has negative temperature coefficient of resistance D. All the above |
12 |

1042 | 5. A solid which is not transparent to visible light and whose conductivity increases with temperature is formed by (a) van der Waals binding (b) metallic binding (c) ionic binding (d) covalent binding (AIEEE 2006) |
12 |

1043 | For the given combination of gates, if the logic states of inputs ( A, B, C ) are as follows ( boldsymbol{A}=boldsymbol{B}=boldsymbol{C}=mathbf{0} ) and ( boldsymbol{A}=boldsymbol{B}= ) ( 1, C=0 ) then the logic states of output D are A. 0,0 B. 0,1 ( c cdot 1,0 ) D. 1 |
12 |

1044 | What is optoelectronic junction devices? Write any two names of optoelectronic junction devices. |
12 |

1045 | 32. Which of the following statements is incorrect? CO Ed (b) (a) The energy gap is larger in Si than in Ge (b) The density of Ge is over 2 times that of Si (c) A npn transistor is represented by the symbol shown in Figure (a). (d) A diode is represented by the symbol shown in Figure (b). |
12 |

1046 | For a CB amplifier current gain is ( 0.54 . ) I the emitter current is ( 6.8 m A ), the collector current will be A . ( 1.7 mathrm{mA} ) в. ( 2.7 mathrm{mA} ) ( c .3 .7 m A ) D. ( 4.7 mathrm{mA} ) |
12 |

1047 | In an unbiased ( n ) -p junction electrons diffuse from n-region to p- region because A. electrons travel across the junction due to potential difference B. electrons concentration in n region is more as compared to that in p-region c. holes in p-region attract them. D. only electrons move from n- to p- region and not the vice-versa. |
12 |

1048 | For detecting the light A. The photodiode has to be forward biased B. The photodiode has to be reversed biased C. The LED has to connected in forward bias mode D. The LED has to be connected in reverse bias mode |
12 |

1049 | 10 | 12 |

1050 | In a metal, the separation between conduction band and valence band is of the order A . 100 eV B. 10 eV ( c cdot 0 e V ) D. 1 eV |
12 |

1051 | At what temperature semiconductors behaves as an ideal insulator? A. ( 273.15^{circ} mathrm{C} ) B . -459.67 ॰ ( F ) c. ( -273^{circ} F ) D. Room temperature |
12 |

1052 | Qoppr 5 s. ( ” ) “. |
12 |

1053 | Energy gap of conductor is A. 0 eV в. 1 eV ( c cdot 2 e V ) D. 3 eV |
12 |

1054 | Fill in the blank. The following truth table with ( A ) and ( B ) as inputs is for ( _{-}- ) gate. ( begin{array}{lll}text { A } & text { B } & text { Output } \ & & \ 1 & text { 0 } & 1 \ text { 1 } & 1 & text { 0 } \ text { 0 } & 1 & 1 \ text { 0 } & text { 0 } & text { 0 }end{array} ) A. AND B. OR c. хок D. NOR |
12 |

1055 | 40. In question 38, the transconductance in 2′ is (a) 0 (b) 0.2 (c) 0.1 (d) 0.05 : |
12 |

1056 | What are the essential components of an oscillator? Draw its block diagram? | 12 |

1057 | Assertion A photocell is called an electric eye. Reason When light is incident on some semiconductor its electrical resistance is reduced 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 |

1058 | Q Type your question B ( c ) ( D ) |
12 |

1059 | A graph of the output from an A.C. generator is given. This is given as: (a) an input to a half wave rectifier (b) an input to a full wave rectifier Give graphic representations of the outputs in the cases (a) and (b). |
12 |

1060 | The gate whose output is low if and only if all inputs are high, is A. NAND B. AND ( c . ) ов D. None of these |
12 |

1061 | What is the conductivity of a semiconductor sample having electron concentration of ( 5 times 10^{18} quad m^{-3}, ) hole concentration of ( 5 times 10^{19} quad m^{-3} ) electron mobility of ( 2.0 m^{2} v^{-1} s^{-1} ) and hole mobility of ( 0.01 m^{2} v^{-1} s^{-1} ? ) (Take charge of electron as ( 1.6 times ) ( left.10^{-19} Cright) ) A ( cdot 1.68(Omega-m)^{-1} ) в. ( 0.59(Omega-m)^{-1} ) c. ( 1.83(Omega-m)^{-1} ) D. ( 1.20(Omega-m)^{-1} ) |
12 |

1062 | A diode is connected to the output of a transformer as shown in the figure given below. Analyse the figure. a) Draw a time-voltage graph for the current obtained across AB. b) What is the function of the diode in the circuit? |
12 |

1063 | State True or False: Saturation current depends on temperature. A. True B. False |
12 |

1064 | A piece of copper and another of germanium are cooled from room temperature to ( 80 mathrm{K} ). The resistance of: A. each of them increases B. each of them decreases c. copper increases and germanium decreases D. copper decreases and germanium increases. |
12 |

1065 | The ( 6 V ) Zener diode is shown in figure has negligible resistance and a knee current of ( 5 m A ). The minimum value of ( R(i n Omega) ) so that the voltage across it does not fall below ( 6 V ) is A. 40 в. 60 ( c cdot 72 ) D. 80 ( E .120 ) |
12 |

1066 | A pnjunction conducts only in forward biased condition. A. True B. False |
12 |

1067 | Application of a forward bias to a ( mathrm{p}-mathrm{n} ) junction A. widens the depletion zone B. increases the potential difference across the depletion zone C. increases the number of donors on the n side D. increases the electric field in the depletion zone |
12 |

1068 | An LED is forward-biased. The diode should be on, but no light is showing. A possible trouble might be : A. the diode is open. B. the series resistor is too small c. the power supply voltage is too high. D. none of these |
12 |

1069 | Figure shows a full wave bridge rectifier circuit. The input a.c. is connected across ( A cdot A ) and ( B ) B. A and C C. ( B ) and ( D ) D. ( B ) and ( C ) |
12 |

1070 | In an experiment of photoelectric effect the number of photoelectrons has to be increased without changing their frequency. The suitable step to be taken about the incident radiation for this is A. increasing intensity without changing frequency B. increase both frequency and intensity C. increase frequency without increasing intensity D. increasing only frequency |
12 |

1071 | For the given circuit of ( boldsymbol{p}-boldsymbol{n} ) junction, the potential barrier is : A. Raised B. Lowered c. Remains same D. Data insufficient |
12 |

1072 | There photo dlodes ( D_{1}, D_{2} ) and ( D_{3} ) are made of semiconductor having band ( operatorname{gap} 2.5 e V, 2 e V ) and ( 3 e V ) respectively. Which one will be able to detect light of wavelength ( 6000 A^{circ} ? ) A. ( D_{1} ) в. ( D_{2} ) ( c cdot D_{3} ) D. ( D_{1} ) and ( D_{2} ) both |
12 |

1073 | In a half wave rectifier, the output is taken across a ( 90 Omega ) load resistor. If the resistance of diode in forward biased condition is ( 10 Omega ), the efficiency of rectification of ac power into dc power is A . ( 40.6 % ) B. ( 81.2 % ) c. ( 73.08 % ) D. ( 36.54 % ) |
12 |

1074 | A change of ( 200 m V ) in base-emitter voltage causes a change of ( 100 mu A ) in the base current. The input resistance of the transistor is ( mathbf{A} cdot 2 K Omega ) в. ( 2 Omega ) c. ( 2 m Omega ) D. 10 KOmega |
12 |

1075 | State whether true or false: The highest occupied energy band is called the valence band and the lowest unoccupied energy band is called the conduction band. A. True B. False |
12 |

1076 | In intrinsic semiconductors: ( mathbf{A} cdot n>p ) В. ( p>n ) c. ( n=p ) D. ( n=0 ) |
12 |

1077 | The colour of light emitted by LED depends on A. Its reverse bias B. The amount of forward current c. Its forward bias D. Type of semiconductor material |
12 |

1078 | When all the inputs of a NAND gate are connected together, the resulting circuit is: A . a NOT gate B. an AND gate c. an OR gate D. a NOR gate |
12 |

1079 | A full wave p-n diode rectifier uses a load resistance of ( 1300 Omega ). No filter is used. If the internal resistance of each diode is ( 9 Omega ), then the efficiency of this full wave rectifier is A. ( 80.64 % ) B . ( 40.6 % ) c. ( 13.9 % ) D. ( 100 % ) |
12 |

1080 | ( sqrt{ }rceil ) ( Gamma ) begin{tabular}{r} ( pi ) \ hline end{tabular} |
12 |

1081 | Two PN junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be PNP PINPINA MPANPA (a) in circuits (1) and (2) (c) in circuits (1) and (3) (b) in circuits (2) and (3) (d) only in circuit (1) |
12 |

1082 | A junction transistor does not have a/an A. emitter-base junction B. base-collectorjunction c. emitter-collector junciton D. none of the above |
12 |

1083 | The value of current in the above diagram is (diode assumed to be ideal one) A. ( 0.1 A ) B. ( 0.01 A ) ( c .1 A ) ( D ) |
12 |

1084 | Select the correct statement from the following: A. A diode can be used as a rectifier B. A triode cannot be used as a rectifier C. The current in a diode is always proportional to the applied voltage D. The linear portion of the I-V characteristic of a triode is used for amplification without distortion |
12 |

1085 | For given logic diagram, output ( boldsymbol{F}=mathbf{1} ) then inputs are: ( mathbf{A} cdot A=0, B=0, C=0 ) ( mathbf{B} cdot A=0, B=1, C=0 ) ( mathbf{c} cdot A=1, B=1, C=1 ) ( mathbf{D} cdot A=0, B=0, C=1 ) |
12 |

1086 | The truth table given below is for (A and B are the inputs, ( Y ) is the output) ( A B Y ) 001 011 101 110 A. NOR B. AND c. хок D. NAND |
12 |

1087 | In a diode, when there is a saturation current, the plate resistance will be A. data insufficient B. zero c. some finite quantity D. infinite |
12 |

1088 | Which of the following is not the function of a NOT gate? A. Stop a signal. B. Invert an input signal c. complement a signal. D. change the logic in a digital circuit |
12 |

1089 | A NOR gate and a NAND gate are connected as shown in the figure. Two different sets of inputs are given to this set up. In the first case, the input to the gates are ( A=0, B=0, C=0 . ) In the second case, the inputs are ( A=1, B=0, C=1 . ) The output D in the first case and second case respectively are A. 0 and 0 B. O and 1 c. 1 and 0 D. 1 and 1 |
12 |

1090 | Find the maximum zener current for the zener diode as shown in figure. Given, ( boldsymbol{V}_{Z}=mathbf{6} boldsymbol{V}, boldsymbol{R}_{Z}=mathbf{1 . 5 Omega}, boldsymbol{R}=mathbf{4 0 0 Omega} ) A. ( 35.00 mathrm{mA} ) в. ( 30.87 m A ) ( c .34 .87 m A ) D. ( 34.87 A ) |
12 |

1091 | Arrange the following in decreasing order of their Band gaps A. conductors, , Insulators, Semiconductors B. Insulators, Semiconductors, Conductors c. Insulators, Conductors, Semiconductors D. conductors, Semiconductors, Insulators |
12 |

1092 | How will you obtain OR, AND gates from the NAND and NOR gates? Write symbol, Boolean formula and truth table. |
12 |

1093 | In n-type semiconductor, the Fermi level is present: A. just below the valence band B. just below the conduction band C. just above the valence band D. in the middle of valence and conduction bands |
12 |

1094 | A p-n photodiode is fabricated from a semiconductor with band gap of ( 2.8 e V ) Can it detect a wavelength of 6000 nm? |
12 |

1095 | Distinguish between Avalanche breakdown and Zener breakdown. | 12 |

1096 | In half-wave rectification, what is the output frequency if the input frequency is ( 50 H z ) What is the output frequency of a fullwave rectifier for the same input |
12 |

1097 | 8. Reverse bias applied to a junction diode (a) lowers the potential barrier (b) raises the potential barrier (c) increases the majority carrier current (d) increases the minority carrier current. |
12 |

1098 | Fill in the blanks: When light falls on the junction of a photo diode, the number of charge carriers and hence the conductivity of the junction A. increases, decreases B. decreases, increases c. decreases, decreases D. increases, increases |
12 |

1099 | The number of photo electrons emitted per second depend on the of incident radiatic. |
12 |

1100 | The value of form factor in case of half wave rectifier is: A . 1.11 в. 1.57 c. 1.27 D. 0.48 |
12 |

1101 | The width of forbidden gap in silicon crystal is ( 1.1 e V . ) When the crystal is converted into an n-type semiconductor, the distance of fermi level from conduction band is A. greater than 0.55 eV B. equal to 0.55 eV c. lesser than 0.55 eV D. equal to ( 1.1 mathrm{eV} ) |
12 |

1102 | The base current of a transistor is ( 105 mu A ) and the collector current is ( 2.05 m A . ) Then ( beta ) of the transistor is ( mathbf{A} cdot 1.952 ) B. 19.52 c. 195.2 D. 1952 |
12 |

1103 | 60. How many NAND gates are required to get a half adder. (a) 3 (6) 5 (c) 9 Tos (d) 7 B |
12 |

1104 | In the following circuit the output ( Y ) becomes zero for the input combinations: ( A cdot A=1, B=0, C=0 ) B. ( A=0, B=1, C=1 ) C. ( A=0, B=0, C=0 ) D. ( A=1, B=1, C=0 ) |
12 |

1105 | With the help of neat labelled circuit diagram explain the working of half wave rectifier using semiconductor diode. Draw the input and output waveforms. |
12 |

1106 | U NUNC Ul Ulese 48. The following truth table corresponds to the logic gate: А в х 0 0 0 0 01. (a) NAND (C) XOR (b) AND (d) OR |
12 |

1107 | A photo diode is made from a semiconductor ( I n_{0.53} . ) As, with ( E_{g}=0.73 ) eV. What is the maximum wavelength which it can detect? ( boldsymbol{h}=mathbf{6 . 6 3} times ) ( 10^{-34} J_{s} ) |
12 |

1108 | The energy gap of silicon is 1.14 eV.The maximum wavelength at which silicon starts energy absorption, will be ( left(h=6.62 times 10^{-34} J s, c=3 times 10^{8} m / sright) ) A ( cdot 10.888 AA ) B ( cdot 108.88 AA ) ( c cdot 1088.8 AA ) D ( cdot 10888 ) 能 |
12 |

1109 | When added an impurity into the silicon which one of the following produces ( n ) type of semi-conductors: A. iron B. magnesium c. aluminium D. phosphorous |
12 |

1110 | In semiconductor physics, what is meant by an oscillator? | 12 |

1111 | The circuit shown in the figure contains two diodes, each with a forward resistance of ( 50 Omega ) and with infinite backward resistance. If the battery voltage is ( 6 mathrm{V} ), the current through the ( 100-Omega ) resistance is A. zer B. ( 0.02 A ) c. ( 0.04 A ) D. ( 0.046 A ) |
12 |

1112 | Assertion ( mathbf{A} ) p-njunction with reverse bias can be used as a photo-diode to measure light intensity. Reason In a reverse bias condition the current is small but is more sensitive to changes in incident light intensity. 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 are correct |
12 |

1113 | A transistor is a/an A . chip B. insulator c. semiconductor D. metal |
12 |

1114 | If the forward voltage in a semiconductor is doubled, the width of depletion layer will A. become half B. become one-fourth c. remain unchanged D. become double |
12 |

1115 | toppr Q Type your question- ( A ) begin{tabular}{cc|c} ( boldsymbol{x} ) & ( boldsymbol{y} ) & ( boldsymbol{z} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( boldsymbol{0} ) & ( mathbf{1} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( boldsymbol{0} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{0} ) end{tabular} B. begin{tabular}{cc|c} ( boldsymbol{x} ) & ( boldsymbol{y} ) & ( boldsymbol{z} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{1} ) end{tabular} ( c ) begin{tabular}{cc|c} ( boldsymbol{x} ) & ( boldsymbol{y} ) & ( boldsymbol{z} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{1} ) end{tabular} ( D ) begin{tabular}{cc|c} ( boldsymbol{x} ) & ( boldsymbol{y} ) & ( boldsymbol{z} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{1} ) end{tabular} |
12 |

1116 | A potential barrier of ( 0.50 mathrm{V} ) exists across of PN Junction. If the depletion region is ( 5.0 times 10^{-7} m ) wide, the intensity of the electric field in this region is A ( cdot 1.0 times 10^{9} mathrm{V} / mathrm{m} ) в. ( 2.0 times 10^{5} mathrm{V} / mathrm{m} ) c. ( 1.0 times 10^{6} mathrm{V} / mathrm{m} ) D. 2.0 ( times 10^{6} mathrm{V} / mathrm{m} ) |
12 |

1117 | ( V_{m} ) is the maximum voltage between trends of the secondary terminal of a transformer used in a half wave rectifier. When the PN junction diode is reverse biased, what will be the potential difference between two ends of the diode? A. zero в. ( frac{V_{m}}{2} ) c. ( V_{m} ) D. ( 2 V_{m} ) |
12 |

1118 | (U) 125 V 68. In question 67, the power gain is (a) 125 x 50 (b) 125 (c) 1.25 50 (d) 2.5 x 104 125 90 |
12 |

1119 | Which of the following is a semiconductor?
This question has multiple correct options |
12 |

1120 | The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 600 nm is incident on it. The energy band gap (in eV) for the semiconductor is A . 1.50 в. .075 c. 2.06 D. 1.35 E . 0.90 |
12 |

1121 | What is rectification? Explain the working of a fullwave rectifier. Draw necessary circuit diagram. | 12 |

1122 | A diode allows the electric current to flow, when it is in forward bias, but if it is in reverse bias it will not allow the electric current to flow. Why? |
12 |

1123 | toppr ( t ) Q Type your question- ( sqrt{1} cdot frac{1}{2} ) ( A ) begin{tabular}{|c|c|c|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{Y} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{1} ) \ hline end{tabular} в. begin{tabular}{|c|c|c|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{Y} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{1} ) \ hline end{tabular} ( c ) begin{tabular}{|c|c|c|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{Y} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{0} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{0} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{0} ) \ hline end{tabular} D. begin{tabular}{|c|c|c|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{Y} ) \ hline ( mathbf{0} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{0} ) & ( mathbf{1} ) \ ( mathbf{0} ) & ( mathbf{1} ) & ( mathbf{1} ) \ ( mathbf{1} ) & ( mathbf{1} ) & ( mathbf{0} ) \ hline end{tabular} |
12 |

1124 | In the figure shown, if the diode forward voltage drops is ( 0.2 V ), the voltage difference between ( A ) and ( B ) is A ( .1 .3 V ) В. ( 2.2 V ) ( c .0 .5 V ) ( D ) |
12 |

1125 | 37. In question 35, the transconductance is (a) 0.1 mho (b) 0.2 mho (c) 0.3 mho (d) 0.4 mho |
12 |

1126 | Diode can work as A. Modulator B. Demodulator C. Rectifier D. Amplifier |
12 |

1127 | Which of the following semiconductor is electrically positive? A. Intrinsic semiconductor B. P-type semiconductor c. N-type semiconductor D. None of these |
12 |

1128 | Which of the following contains a covalent bond? A. copper в. ( N a C l ) c. germanium D. helium |
12 |

1129 | In the Boolean Algebra A.B is same. ( A cdot A+B ) B. A-B c. ( A-B ) D. Adivs |
12 |

1130 | What is a transistor? Why is it so called? What are the advantages of transistors over vacuum tubes? |
12 |

1131 | 61. Which circuit adds two bits P and Q to provide the corre range of outputs for a half-adder? (a) Po EX-OR Sum AND Carry (b) P EX-OR Sum NAND Carry EX-OR Sum OR Carry (d) pe AND Sum EX-OR Carry |
12 |

1132 | An amplifier has a voltage gain ( boldsymbol{A}_{boldsymbol{v}}= ) 1000. The voltage gain in dB is: ( mathbf{A} cdot 30 d B ) В. ( 60 d B ) c. ( 3 d B ) ( mathbf{D} cdot 20 d B ) |
12 |

1133 | (a) Draw the circuit diagram of a ful wave rectifier using ( boldsymbol{p}-boldsymbol{n} ) junction diode Explain its working and show the |
12 |

1134 | The I V characteristics of solar cell is drawn in the fourth quadrant of the coordinate axes because A. a solar cell does not draw current but supplies the same to the load B. a solar cell draws current but supplies no current to the load c. a solar cell draws voltage and supplies current to the load D. a solar cell draws current but supplies voltage to the load |
12 |

1135 | Examples of opto-electronic devices are This question has multiple correct options A. Light Emitting Diodes (LED) B. Zener diode c. Solar cells D. Photodiodes |
12 |

1136 | How many NAND gates are needed to perform the logic function X.Y? A . 1 B. 2 ( c cdot 3 ) ( D ) |
12 |

1137 | ( left(A_{V}right) ) and load resistance ( left(R_{L}right) ) is : ( A ) ( B ) ( c ) D. |
12 |

1138 | In an insulator, band gap of the order of? A ( .0 .1 e V ) B. ( 1 e V ) c. ( 5 e V ) D. ( 100 e V ) E . ( 1 mathrm{MeV} ) |
12 |

1139 | Draw the circuit diagram of a voltage regulator using zener diode. | 12 |

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