Correct4
Incorrect-1
At absolute zero, Si acts as
non-metal
metal
insulator
none of these.
Correct4
Incorrect-1
By increasing the temperature, the specific resistance of a conductor and a semiconductor
increases for both
decreases for both
increases, decreases
decreases, increases.
Correct4
Incorrect-1
The energy band gap is maximum in insulators.
metals
superconductors
insulators
semiconductors.
Correct4
Incorrect-1
The part of a transistor which is most heavily doped to produce large number of majority carriers is
emitter
base
collector
can be any of the above three.
Correct4
Incorrect-1
Formation of covalent bonds in compounds exhibits
wave nature of electron
particle nature of electron
both wave and particle nature of electron
none of these.
Correct4
Incorrect-1
A strip of copper and another germanium are cooled from room temperature to {tex} 80 \mathrm { K } {/tex}. The resistance of
each of these decreases
copper strip increases and that of germanium decreases
copper strip decreases and that of germanium increases
each of these increases.
Correct4
Incorrect-1
The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the
crystal structure
variation of the number of charge carriers with temperature
type of bonding
variation of scattering mechanism with temperature.
Correct4
Incorrect-1
In the middle of the depletion layer of a reverse- biased {tex} p - n {/tex} junction, the
electric field is zero
potential is maximum
electric field is maximum
potential is zero.
Correct4
Incorrect-1
When npn transistor is used as an amplifier
electrons move from base to collector
holes move from emitter to base
electrons move from collector to base
holes move from base to emitter.
Correct4
Incorrect-1
For a transistor amplifier in common emitter configuration for load impedance of {tex} 1 \mathrm { k } \Omega {/tex} {tex} \left( h _ { f e } = 50 \text { and } h _ { o e } = 25 \right) {/tex} the current gain is
{tex} - 5.2 {/tex}
{tex} - 15.7 {/tex}
{tex} - 24.8 {/tex}
{tex} - 48.78 {/tex}
Correct4
Incorrect-1
A piece of copper and another of germanium are cooled from room temperature to {tex} 77 \mathrm { K } , {/tex} the resistance of
each of them increases
each of them decreases
copper decreases and germanium increases
copper increases and germanium decreases.
Correct4
Incorrect-1
The manifestation of band structure in solids is due to
Heisenberg's uncertainty principle
Pauli's exclusion principle
Bohr's correspondence principle
Boltzmann's law
Correct4
Incorrect-1
When {tex} p - n {/tex} junction diode is forward biased, then
the depletion region is reduced and barrier height is increased
the depletion region is widened and barrier height is reduced.
both the depletion region and barrier height are reduced
both the depletion region and barrier height are increased
Correct4
Incorrect-1
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}
0.7 {tex} \mathrm { eV } {/tex}
1.1 {tex}\mathrm { eV } {/tex}
2.5 {tex} \mathrm { eV } {/tex}
Correct4
Incorrect-1
In a common base amplifier, the phase difference between the input signal voltage and output voltage is
0
{tex} \pi / 2 {/tex}
{tex} \pi / 4 {/tex}
{tex} \pi {/tex}
Correct4
Incorrect-1
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}
70.7 {tex} \mathrm { Hz } {/tex}
50 {tex} \mathrm { Hz } {/tex}
25 {tex}\mathrm { Hz } {/tex}
Correct4
Incorrect-1
A solid which is transparent to visible light and whose conductivity increases with temperature is formed by
metallic binding
ionic binding
covalent binding
van der Waals binding
Correct4
Incorrect-1
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?
{tex} 4 / 7 {/tex}
{tex} 5 / 8 {/tex}
{tex} 4 / 5 {/tex}
{tex} 5/4 {/tex}
Correct4
Incorrect-1
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
48
49
50
51
Correct4
Incorrect-1
In the following, which one of the diodes is reverse biased?
Correct4
Incorrect-1
The circuit has two oppositely connect ideal diodes in parallel. What is the current following in the circuit?
{tex} 1.71 \mathrm { A } {/tex}
{tex} 2.00 \mathrm { A } {/tex}
{tex} 2.31 \mathrm { A } {/tex}
Correct4
Incorrect-1
If in a {tex} p - n {/tex} junction diode, a square input signal of {tex} 10 \mathrm { V } {/tex} is applied as shown
Correct4
Incorrect-1
Carbon, silicon and gemanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?
The number of free electrons for conduction is significant only in Si and Ge but small in C.
The number of free conduction electrons is significant in C but small in Si and Ge.
The number of free conduction electrons is negligibly small in all the three.
The number of free electrons for conduction is significant in all the three.
Correct4
Incorrect-1
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.
It is an npn transistor with {tex} R {/tex} as base.
It is a pnp transistor with {tex} R {/tex} as collector.
It is a pnp transistor with {tex} R {/tex} as emitter.
Correct4
Incorrect-1
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
NOR gate
AND gate
NAND gate
