NEET > Electronic Devices

Explore popular questions from Electronic Devices for NEET. This collection covers Electronic Devices previous year NEET questions hand picked by popular teachers.


Q 1.    

Correct4

Incorrect-1

Bonding in a semiconducting crystal is

A

metallic

B

ionic

covalent

D

van der Waals

Explanation

Q 2.    

Correct4

Incorrect-1

A solid that is not transparent to visible light and whose electrical conductivity increases with temperature is formed by

A

ionic bonding

covalent bonding

C

metallic bonding

D

van der Waals bonding

Explanation

Q 3.    

Correct4

Incorrect-1

When the temperature of a semiconductor is increased, its electrical conductivity

increases

B

remains the same

C

decreases

D

first increases and then decreases

Explanation

Q 4.    

Correct4

Incorrect-1

With the rise in temperature, the specific resistance of a semiconductor

A

increases

B

remains unchanged

decreases

D

first decreases and then increases

Explanation

Q 5.    

Correct4

Incorrect-1

A piece of copper and another of germanium are cooled from room temperature to {tex} 80 \mathrm { K } {/tex}. The resistance of

A

each of them increases

B

each of them decreases

C

copper increases and germanium decreases

copper decreases and germanium increases

Explanation

Q 6.    

Correct4

Incorrect-1

In a semiconductor the forbidden energy gap between the valence band and the conduction band is of the order of

{tex} 1\ \mathrm { eV } {/tex}

B

{tex} 5 \ \mathrm { eV } {/tex}

C

{tex} 1 \ \mathrm { keV } {/tex}

D

{tex} 1\ \mathrm { MeV } {/tex}

Explanation

Q 7.    

Correct4

Incorrect-1

The energy gap between the conduction band and the valence band in a material is 0.7 eV. It is

A

a metal

B

an insulator

a semiconductor

D

an alloy

Explanation

Q 8.    

Correct4

Incorrect-1

The impurity atoms with which pure silicon should be doped to make a p-type semiconductor are those of

A

phosphorus

boron

C

antimony

D

none of these

Explanation

Q 9.    

Correct4

Incorrect-1

To obtain a p-type semiconductor, we need to dope pure silicon with

aluminium

B

phosphorus

C

antimony

D

none of these

Explanation

Q 10.    

Correct4

Incorrect-1

If germanium has to be doped with a donor impurity, the foreign atom should be

A

tetravalent

pentavalent

C

trivalent

D

none of the above

Explanation

Q 11.    

Correct4

Incorrect-1

When the conductivity of a semiconductor is only due to the breaking of the covalent bonds, the semiconductor is called

A

donor

B

acceptor

intrinsic

D

extrinsic

Explanation

Q 12.    

Correct4

Incorrect-1

A pure semiconductor has

A

an infinite resistance at {tex} 0 ^ { \circ } \mathrm { C } {/tex}

B

a finite resistance which does not depend upon temperature

a finite resistance which decreases with temperature

D

a finite resistance which increases with temperature

Explanation

Q 13.    

Correct4

Incorrect-1

A p-type semiconductor is
(i) a silicon crystal doped with arsenic impurity
(ii) a silicon crystal doped with aluminium impurity
(iii) a germanium crystal doped with boron impurity
(iv) a germanium crystal doped with phosphorus impurity
State if:

A

{tex}(i){/tex} and {tex}(ii){/tex} are correct

{tex}(ii){/tex} and {tex}( iii){/tex} are correct

C

{tex}(i){/tex} and {tex}( iv){/tex} are correct

D

only {tex}(i){/tex} is correct.

Explanation

Q 14.    

Correct4

Incorrect-1

A hole in a p-type semiconductor is

A

an excess electron

a missing electron

C

a missing atom

D

a donor level

Explanation

Q 15.    

Correct4

Incorrect-1

n-type germanium is obtained on doping intrinsic germanium with

phosphorus

B

aluminium

C

boron

D

gold

Explanation

Q 16.    

Correct4

Incorrect-1

An n-type semiconductor is formed

A

when germanium crystal is doped with an impurity containing three valence electrons

when germanium crystal is doped with an impurity containing five valence electrons

C

from pure germanium

D

from pure silicon

Explanation

Q 17.    

Correct4

Incorrect-1

When arsenic is added as an impurity to silicon, the resulting material is

n-type semiconductor

B

n-type conductor

C

p-type semiconductor

D

p-type conductor

Explanation

Q 18.    

Correct4

Incorrect-1

A typical example of a semiconductor is

A

platinum

germanium

C

quartz

D

mica

Explanation

Q 19.    

Correct4

Incorrect-1

Majority carriers in a semiconductor are

A

holes in n-type and electrons in p-type

B

holes in both n-type and p-type

electrons in n-type and holes in p-type

D

electrons in both n-type and p-type

Explanation

Q 20.    

Correct4

Incorrect-1

In an intrinsic semiconductor

A

only electrons are responsible for the flow of current

B

only holes are responsible for the flow of current

both holes and electrons carry current and their number is the same

D

both holes and electrons carry current but electrons are the majority carriers

Explanation

Q 21.    

Correct4

Incorrect-1

In a pn junction, the barrier potential offers opposition to only

majority carriers in both regions

B

minority carriers in both regions

C

electrons in n-region

D

holes in p-region

Explanation

Q 22.    

Correct4

Incorrect-1

pn junction diode works as insulator, if connected

A

to ac source

B

in forward bias

in reverse bias

D

either to ac source or in reverse bias.

Explanation

Q 23.    

Correct4

Incorrect-1

The resistance of a pn junction in forward bias is

A

zero

low

C

high

D

infinite

Explanation

Q 24.    

Correct4

Incorrect-1

The reverse biasing in a junction diode

A

decreases the potential barrier

increases the potential barrier

C

increases the number of minority charge carriers

D

increases the number of majority charge carriers

Explanation

Q 25.    

Correct4

Incorrect-1

A pn junction is said to be reverse biased when

A

no potential difference is applied across it

B

a potential difference is applied across it making p-region positive and n-region negative

a potential difference is applied across it making p-region negative and n-region positive

D

a magnetic field is applied in the region of the junction

Explanation