36 + Interview Questions in SOLID-AND-SEMICONDUCTOR-DEVICES IN GENERAL AWARENESS Page 1 InterviewSolution

1.	In a `p-n` junction photo cell, the value of the photo electromotive force produced by monochromatic light is proportional toA. to barrier voltage at the p-n junctionB. the intensity of the light falling on the cellC. the frequency of the light falling on the cellD. the voltage applied at the p-n junction
Answer» Correct Answer - B

Discussion

2.	The diode used in the circuit shown in the figure has a constant voltage drop of `0.5 V` at all currents and a maximum power rating fo `100` milliwatts. What should be the value of the resistor `R`, connected in series with the diode for obtaining maximum current? A. `200 Omega`B. `6.67 Omega`C. `5 Omega`D. `1.5 Omega`
Answer» Correct Answer - C

Discussion

3.	To obtain a `P`-type germanium semiconductor, it must be dopped withA. phosphorusB. indiumC. antimonyD. arsenic
Answer» Correct Answer - B

Discussion

4.	If a small amount of antimony is added to germanium crystalA. the antimony becomes an acceptor atomB. three will be more free electrons than holes in the semiconductorC. its resistance is increasedD. it becomes a p-type semiconductor
Answer» Correct Answer - B

Discussion

5.	Symbolic representation of four logic gates are shown as (i) Pick out which ones are for AND, NAND and NOT gates, respectively.A. (iii), (ii) and (i)B. (iii), (ii) and (iv)C. (ii), (iv) and (iii)D. (ii), (iii) and (iv)
Answer» Correct Answer - C

Discussion

6.	Choose the only false statement form the followingA. Substances with energy gap of the order of `10eV` are insulatorsB. The conductivity of a semiconductor increases with increases in temperatureC. In conductors the valence and conduction bands may overlapD. The resistivity of a semiconductor increases with increase in temperature
Answer» Correct Answer - D

Discussion

7.	Copper has face centred cubic `(fc c)` lattice with interatomic spacing equal to `2.54 Å`. The value of the lattice constant for this lattice isA. `1.27 Å`B. `5.08 Å`C. `2.54 Å`D. `3.59 Å`
Answer» Correct Answer - D

Discussion

8.	A n-p-n transisitor is connected in common emitter configuration in a given amplifier. A load resistance of `800 Omega` is connected in the collector circuit and the voltage drop across it is `0.8 V`. If the current amplification factor is `0.96` and the input resistance of the circuits is `192 Omega`, the voltage gain and the power gain of the amplifier will respectively beA. 3.69, 3.84B. 4,4C. 4,3.69D. 4, 3.84
Answer» Correct Answer - D

Discussion

9.	For CE transistor amplifier, the audio signal voltage across the collector resistance of `2 kOmega` is 4V. If the current amplification factor of the transistor is 100 and the base resistance is `1kOmega`, then the input signal voltage isA. `10 mV`B. `20mV`C. `30mV`D. `15mV`
Answer» Correct Answer - B

Discussion

10.	In a CE transistor amplifier, the audio signal voltage across the collector resistance of `2kOmega` is `2V`. If the base resistance is `1kOmega` and the current amplification of the transistor is 100, the input signal voltage is:A. `0.1V`B. `1.0V`C. `1mV`D. `10 mV`
Answer» Correct Answer - D

Discussion

11.	The transfer ration of a transistor is `50`. The input resistance of the transistor when used in the common -emitter configuration is `1 kOmega`. The peak value for an `A.C.` input voltage of `0.01 V` peak isA. `100 mu A`B. `0.01 mA`C. `0.25 mA`D. `500 mu A`
Answer» Correct Answer - D

Discussion

12.	A transistor is operated in common emitter configuration at constant collector voltage `V_(c)=1.5 V` such that a change in the base current from `100 muA` to `150 muA` produces a change in the collector current from `5 mA` to `10 mA`. The current gain `(beta)` isA. 67B. 75C. 100D. 50
Answer» Correct Answer - C

Discussion

13.	In a common emitter transistor transistor amplifier, the audio signal voltage across the collector is `3kOmega`. If current gain is 100 and the base resistance is `2kOmega`, the voltage and power gain of the amplifier areA. 200 and 100B. 15 and 200C. 150 and 15000D. 20 and 2000
Answer» Correct Answer - C

Discussion

14.	In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductor 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 willA. `(2)/(3)G`B. `1.5G`C. `(1)/(3)G`D. `(5)/(4)G`
Answer» Correct Answer - A

Discussion

15.	A common emitter amplifier has a voltage gain of `50`, an input impedence of `100 Omega` and an output impedence of `200 Omega`. The power gain of the of the amplifier isA. 500B. 1000C. 1250D. 50
Answer» Correct Answer - C

Discussion

16.	In a common-base configuration of a transistor `(Delta i)/(Delta i_(e)) = 0.98`, then current gain in common emitter configuration of transistor will beA. 49B. 98C. 4.9D. 24.5
Answer» Correct Answer - A

Discussion

17.	The current gain for a transistor working as a common-base amplifier is `0.96`. If the emitter current is `7.2 mA`, the base current will beA. `0.29 mA`B. `0.35 mA`C. `0.39 mA`D. `0.43 mA`
Answer» Correct Answer - A

Discussion

18.	Diamond is very hard, becauseA. it is covalent solidB. it has large cohesive energyC. high melting pointD. insoluble in all solvents
Answer» Correct Answer - B

Discussion

19.	Application of a forward biase to a `p-n` junction:A. increases the number of donors on the n-sideB. increases the electric field in the depletion zoneC. increases the potential difference across the depletion zoneD. widens the depletion zone
Answer» Correct Answer - A

Discussion

20.	In semiconductors at a room tempretureA. the valence band is partially empty and the conductor band is partially filledB. the valence band is completely filled and the conduction band is partially filledC. the valence band is completely filledD. the conduction band is completely empty
Answer» Correct Answer - A

Discussion

21.	The relation between `alpha` and `beta` parameters of current gains for a transistors is given byA. `beta = (1+alpha)/(beta)`B. `alpha = (beta)/(1+beta)`C. `alpha = (beta)/(1-beta)`D. `beta = (alpha)/(1+alpha)`
Answer» Correct Answer - B

Discussion

22.	What is the output `Y` in the following circuit, when all the three output `A,B,C` are first `0` and then `1`? A. 0, 1B. 0, 0C. 1, 0D. 1, 1
Answer» Correct Answer - C

Discussion

23.	If a `p-n` junction diode, a square input signal of `10 V` is applied as shown. Then the out put signal across `R_(L)` will be .A. B. C. D.
Answer» Correct Answer - D

Discussion

24.	Depletion layer consists ofA. electronsB. protonsC. mobile chargeD. immobile ions
Answer» Correct Answer - D

Discussion

25.	If internal resistance of cell is negligible, then current flowing through the circuit is A. `(3)/(50)A`B. `(5)/(50)A`C. `(4)/(50)A`D. `(2)/(50)A`
Answer» Correct Answer - B

Discussion

26.	Si and Cu are cooled to a temperature of `300 K`, then resistivityA. for Si increases and for Cu decreasesB. for Cu increases and for Si decreasesC. decreases for both Si and CuD. increases for both Si and Cu
Answer» Correct Answer - A

Discussion

27.	The following figure shows a logic gate circuit with two inputs A and B output C. The voltage waveforms of A,B and C are as shown in second figure given below :- The logic circuit gate is :-A. AND gateB. NAND gateC. NOR gateD. OR gate
Answer» Correct Answer - A

Discussion

28.	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 A. p-type semiconductorB. insulatorC. metalD. n-type semiconductor
Answer» Correct Answer - A

Discussion

29.	The following circuit represents:A. OR gateB. XOR gateC. AND gateD. NAND gate
Answer» Correct Answer - B

Discussion

30.	The number of atoms per unit cell in bcc lattice isA. 1B. 2C. 4D. 9
Answer» Correct Answer - B

Discussion

31.	If the lattice parameter for a crystalline structure is `3.6Å`, then the atomic radius is fcc crystals isA. `1.81 Å`B. `2.10Å`C. `2.92 Å`D. `1.27 Å`
Answer» Correct Answer - D

Discussion

32.	Which logic gate is represented by the following combination of logic gates A. ORB. NANDC. ANDD. NOR
Answer» Correct Answer - C

Discussion

33.	Which one of the following gates will have an output of 1 ? A. AB. BC. CD. D
Answer» Correct Answer - C

Discussion

34.	Which of the following when added as an impurity into silicon produces n-type semicondutor ?A. PB. AlC. BD. Mg
Answer» Correct Answer - A

Discussion

35.	In junction diode, the holes are due toA. protonsB. extra electronsC. neutronsD. missing eletrons
Answer» Correct Answer - D

Discussion

36.	Barrier potential of a `p-n` junction diode does not depend onA. forward biasB. doping densityC. diode designD. temperature
Answer» Correct Answer - C

Discussion

Explore topic-wise InterviewSolutions in .

To obtain a `P`-type germanium semiconductor, it must be dopped withA. phosphorusB. indiumC. antimonyD. arsenic

If a small amount of antimony is added to germanium crystalA. the antimony becomes an acceptor atomB. three will be more free electrons than holes in the semiconductorC. its resistance is increasedD. it becomes a p-type semiconductor

Symbolic representation of four logic gates are shown as (i) Pick out which ones are for AND, NAND and NOT gates, respectively.A. (iii), (ii) and (i)B. (iii), (ii) and (iv)C. (ii), (iv) and (iii)D. (ii), (iii) and (iv)

Copper has face centred cubic `(fc c)` lattice with interatomic spacing equal to `2.54 Å`. The value of the lattice constant for this lattice isA. `1.27 Å`B. `5.08 Å`C. `2.54 Å`D. `3.59 Å`

For CE transistor amplifier, the audio signal voltage across the collector resistance of `2 kOmega` is 4V. If the current amplification factor of the transistor is 100 and the base resistance is `1kOmega`, then the input signal voltage isA. `10 mV`B. `20mV`C. `30mV`D. `15mV`

In a CE transistor amplifier, the audio signal voltage across the collector resistance of `2kOmega` is `2V`. If the base resistance is `1kOmega` and the current amplification of the transistor is 100, the input signal voltage is:A. `0.1V`B. `1.0V`C. `1mV`D. `10 mV`

The transfer ration of a transistor is `50`. The input resistance of the transistor when used in the common -emitter configuration is `1 kOmega`. The peak value for an `A.C.` input voltage of `0.01 V` peak isA. `100 mu A`B. `0.01 mA`C. `0.25 mA`D. `500 mu A`

A transistor is operated in common emitter configuration at constant collector voltage `V_(c)=1.5 V` such that a change in the base current from `100 muA` to `150 muA` produces a change in the collector current from `5 mA` to `10 mA`. The current gain `(beta)` isA. 67B. 75C. 100D. 50

In a common emitter transistor transistor amplifier, the audio signal voltage across the collector is `3kOmega`. If current gain is 100 and the base resistance is `2kOmega`, the voltage and power gain of the amplifier areA. 200 and 100B. 15 and 200C. 150 and 15000D. 20 and 2000

A common emitter amplifier has a voltage gain of `50`, an input impedence of `100 Omega` and an output impedence of `200 Omega`. The power gain of the of the amplifier isA. 500B. 1000C. 1250D. 50

In a common-base configuration of a transistor `(Delta i)/(Delta i_(e)) = 0.98`, then current gain in common emitter configuration of transistor will beA. 49B. 98C. 4.9D. 24.5

The current gain for a transistor working as a common-base amplifier is `0.96`. If the emitter current is `7.2 mA`, the base current will beA. `0.29 mA`B. `0.35 mA`C. `0.39 mA`D. `0.43 mA`

Diamond is very hard, becauseA. it is covalent solidB. it has large cohesive energyC. high melting pointD. insoluble in all solvents

Application of a forward biase to a `p-n` junction:A. increases the number of donors on the n-sideB. increases the electric field in the depletion zoneC. increases the potential difference across the depletion zoneD. widens the depletion zone

In semiconductors at a room tempretureA. the valence band is partially empty and the conductor band is partially filledB. the valence band is completely filled and the conduction band is partially filledC. the valence band is completely filledD. the conduction band is completely empty

The relation between `alpha` and `beta` parameters of current gains for a transistors is given byA. `beta = (1+alpha)/(beta)`B. `alpha = (beta)/(1+beta)`C. `alpha = (beta)/(1-beta)`D. `beta = (alpha)/(1+alpha)`

What is the output `Y` in the following circuit, when all the three output `A,B,C` are first `0` and then `1`? A. 0, 1B. 0, 0C. 1, 0D. 1, 1

If a `p-n` junction diode, a square input signal of `10 V` is applied as shown. Then the out put signal across `R_(L)` will be .A. B. C. D.

Depletion layer consists ofA. electronsB. protonsC. mobile chargeD. immobile ions

If internal resistance of cell is negligible, then current flowing through the circuit is A. `(3)/(50)A`B. `(5)/(50)A`C. `(4)/(50)A`D. `(2)/(50)A`

Si and Cu are cooled to a temperature of `300 K`, then resistivityA. for Si increases and for Cu decreasesB. for Cu increases and for Si decreasesC. decreases for both Si and CuD. increases for both Si and Cu

The following figure shows a logic gate circuit with two inputs A and B output C. The voltage waveforms of A,B and C are as shown in second figure given below :- The logic circuit gate is :-A. AND gateB. NAND gateC. NOR gateD. OR gate

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 A. p-type semiconductorB. insulatorC. metalD. n-type semiconductor

The following circuit represents:A. OR gateB. XOR gateC. AND gateD. NAND gate

The number of atoms per unit cell in bcc lattice isA. 1B. 2C. 4D. 9

If the lattice parameter for a crystalline structure is `3.6Å`, then the atomic radius is fcc crystals isA. `1.81 Å`B. `2.10Å`C. `2.92 Å`D. `1.27 Å`

Which logic gate is represented by the following combination of logic gates A. ORB. NANDC. ANDD. NOR

Which one of the following gates will have an output of 1 ? A. AB. BC. CD. D

Which of the following when added as an impurity into silicon produces n-type semicondutor ?A. PB. AlC. BD. Mg

In junction diode, the holes are due toA. protonsB. extra electronsC. neutronsD. missing eletrons

Barrier potential of a `p-n` junction diode does not depend onA. forward biasB. doping densityC. diode designD. temperature