On account of the disruption in education due to the corona pandemic, we're opening up our platform for teachers, free of cost. Know More →

JEE Main

Explore popular questions from Electronic Devices & Semiconductor for JEE Main. This collection covers Electronic Devices & Semiconductor previous year JEE Main questions hand picked by experienced teachers.

Select Subject

Physics

Chemistry

Mathematics

Electronic Devices & Semiconductor

Correct Marks 4

Incorrectly Marks -1

Q 1. In the middle of the depletion layer of a reverse- biased {tex} p - n {/tex} junction, the

electric field is zero

B

potential is maximum

C

electric field is maximum

D

potential is zero.

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 2. In the circuit below, {tex} A {/tex} and {tex} B {/tex} represent two inputs and {tex} C {/tex} represents the output. The circuit represents

OR gate

B

NOR gate

C

AND gate

D

NAND gate

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 3. If in a {tex} p - n {/tex} junction diode, a square input signal of {tex} 10 \mathrm { V } {/tex} is applied as shown

B

C

D

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 4. In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be

100 {tex} \mathrm { Hz } {/tex}

B

70.7 {tex} \mathrm { Hz } {/tex}

C

50 {tex} \mathrm { Hz } {/tex}

D

25 {tex}\mathrm { Hz } {/tex}

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 5. In common base mode of a transistor, the collector current is {tex} 5.488 \mathrm { mA } {/tex} for an emitter current of {tex} 5.60 \mathrm { mA } {/tex}. The value of the base current amplification factor ( {tex} \beta {/tex} ) will be

A

48

49

C

50

D

51

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 6. The circuit has two oppositely connect ideal diodes in parallel. What is the current following in the circuit?

A

B

{tex} 1.71 \mathrm { A } {/tex}

{tex} 2.00 \mathrm { A } {/tex}

D

{tex} 2.31 \mathrm { A } {/tex}

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 7. A solid which is transparent to visible light and whose conductivity increases with temperature is formed by

metallic binding

B

ionic binding

C

covalent binding

D

van der Waals binding

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 8. In the ratio of the concentration of electrons that of holes in a semiconductor is {tex} 7 / 5 {/tex} and the ratio of currents is {tex} 7 / 4 {/tex} then what is the ratio of their drift velocities?

A

{tex} 4 / 7 {/tex}

B

{tex} 5 / 8 {/tex}

C

{tex} 4 / 5 {/tex}

{tex} 5/4 {/tex}

Explanation



Correct Marks 4

Incorrectly Marks -1

Q 9. The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than {tex} 2480 \mathrm { nm } {/tex} is incident on it. The band gap in (eV) for the semiconductor is

0.5 {tex} \mathrm { eV } {/tex}

B

0.7 {tex} \mathrm { eV } {/tex}

C

1.1 {tex}\mathrm { eV } {/tex}

D

2.5 {tex} \mathrm { eV } {/tex}

Explanation





Correct Marks 4

Incorrectly Marks -1

Q 10. A working transistor with its three legs marked {tex} P , {/tex} {tex} Q {/tex} and {tex} R {/tex} is tested using a multimeter. No conduction is found between {tex} P {/tex} and {tex} Q . {/tex} By connecting the common (negative) terminal of the multimeter to {tex} R {/tex} and the other (positive) terminal to {tex} P {/tex} or {tex} Q {/tex}, some resistance is seen on the multimeter. Which of the following is true for the transistor?

It is an npn transistor with {tex} R {/tex} as collector.

B

It is an npn transistor with {tex} R {/tex} as base.

C

It is a pnp transistor with {tex} R {/tex} as collector.

D

It is a pnp transistor with {tex} R {/tex} as emitter.

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 11. In a common base amplifier, the phase difference between the input signal voltage and output voltage is

0

B

{tex} \pi / 2 {/tex}

C

{tex} \pi / 4 {/tex}

D

{tex} \pi {/tex}

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 12. In the following, which one of the diodes is reverse biased?

B

C

D

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 13. When npn transistor is used as an amplifier

electrons move from base to collector

B

holes move from emitter to base

C

electrons move from collector to base

D

holes move from base to emitter.

Explanation


Correct Marks 4

Incorrectly Marks -1

Q 14. In a common base amplifier the phase difference between the input signal voltage and the output voltage is

0

B

{tex} \pi / 4 {/tex}

C

{tex} \pi / 2 {/tex}

D

{tex} \pi {/tex}

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 15. For the given combination of gates, if the logic states of inputs {tex} A , B , {/tex} {tex} C {/tex} are as follows {tex} A = B = C = 0 {/tex} and {tex} A = B = 1 , C = 0 {/tex} then the logic states of output {tex} D {/tex} are

A

{tex} 0,0 {/tex}

B

{tex} 0,1 {/tex}

C

{tex} 1,0 {/tex}

{tex} 1,1 {/tex}

Explanation



Correct Marks 4

Incorrectly Marks -1

Q 16. While a collector to emitter voltage is constant in a transistor, the collector current changes by {tex} 8.2 \ { mA } {/tex} when the emitter current changes by {tex} 8.3 \ { m } A {/tex}. The value of forward current ratio {tex} h {/tex} is

{tex}82{/tex}

B

{tex}83{/tex}

C

{tex}8.2{/tex}

D

{tex}8.3{/tex}

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 17. The output of a {tex}NAND{/tex} gate is 0

A

If both inputs are 0

B

If one input is 0 and the other input is 1

If both inputs are 1

D

Either if both inputs are 1 or if one of the inputs is 1 and the other 0

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 18. A semiconductor {tex}X{/tex} is made by doping a germanium crystal with arsenic {tex} (Z = 33){/tex}. A second semiconductor {tex}Y{/tex} is made by doping germanium with indium {tex} (Z = 49){/tex}. The two are joined end to end and connected to a battery as shown. Which of the following statements is correct

A

{tex} X {/tex}is {tex} P {/tex}-type, {tex} Y {/tex}is {tex} N {/tex}-type and the junction is forward biased

B

{tex} X {/tex}is {tex} N {/tex}-type, {tex} Y {/tex}is {tex} P {/tex}-type and the junction is forward biased

C

{tex} X {/tex}is {tex} P {/tex}-type, {tex} Y {/tex}is {tex} N {/tex}-type and the junction is reverse biased

{tex} X {/tex}is {tex} N {/tex}-type, {tex} Y {/tex}is {tex} P {/tex}-type and the junction is reverse biased

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 19. In a {tex}PNP{/tex} transistor the base is the {tex} N {/tex}-region. Its width relative to the {tex}P{/tex}-region is

Smaller

B

Larger

C

Same

D

Not related

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 20. The combination of gates shown be a process

A

{tex}\mathrm {AND}{/tex} gate

B

{tex}\mathrm{XOR}{/tex} gate

C

{tex}\mathrm{NOR}{/tex} gate

{tex}\mathrm{NAND}{/tex} gate

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 21. A common emitter amplifier is designed with {tex} N P N {/tex} transistor {tex} ( \alpha = {/tex} {tex} 0.99 ) . {/tex} The input impedance is {tex} 1\ { K } \Omega {/tex} and load is {tex} 10\ { K } \Omega {/tex}. The voltage gain will be

A

{tex}9.9{/tex}

B

{tex}99{/tex}

{tex}990{/tex}

D

{tex}9900{/tex}

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 22. The relation between {tex} \alpha {/tex} and {tex} \beta {/tex} parameters of current gains for a transistors is given by

A

{tex} \alpha = \frac { \beta } { 1 - \beta } {/tex}

{tex} \alpha = \frac { \beta } { 1 + \beta } {/tex}

C

{tex} \alpha = \frac { 1 - \beta } { \beta } {/tex}

D

{tex} \alpha = \frac { 1 + \beta } { \beta } {/tex}

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 23. A gate in which all the inputs must be low to get a high output is called

A

A {tex}\mathrm{NAND}{/tex} gate

An Invertor{tex} {/tex}

C

A {tex}\mathrm{NOR}{/tex} gate

D

An {tex}\mathrm{AND}{/tex} gate

Correct Marks 4

Incorrectly Marks -1

Q 24. The {tex} i - V {/tex} characteristic of a {tex} P - N {/tex} junction diode is shown below. The approximate dynamic resistance of the {tex}P-N{/tex} junction when a forward bias of {tex}2{/tex} {tex}volt{/tex} is applied

A

{tex} 1\ \Omega {/tex}

{tex} 0.25\ \Omega {/tex}

C

{tex} 0.5\ \Omega {/tex}

D

{tex} 5\ \Omega {/tex}

Explanation

Correct Marks 4

Incorrectly Marks -1

Q 25. On increasing the reverse bias to a large value in a {tex} P N- {/tex}junction diode, current

A

Increases slowly

B

Remains fixed

Suddenly increases

D

Only fixed ions

Explanation