Semiconductor Physics and Diodes MCQs

Question 1

The transferred?electron bulk effect occurs in

Accepted Answer

gallium arsenide

Answer

germanium

Answer

silicon

Answer

none of these

Question 2

The biggest advantage of TRAPATT diode over IMPATT diode is its

Accepted Answer

higher efficiency

Answer

higher output

Answer

lower noise

Answer

capability to operate at higher frequencies

Question 3

A varactor diode may be advantageous at microwave frequencies (indicate false answer)

Accepted Answer

as an oscillator

Answer

for electronic tuning

Answer

as a parametric amplifier

Answer

for frequency multiplication

Question 4

If high order frequency multiplication is required from a diode multiplier

Accepted Answer

a step recovery diode must be used

Answer

the resistive cut-off frequency must be high

Answer

a small value of base resistance is required

Answer

none of these

Question 5

Negative resistance is obtained with a Gunn diode because of

Accepted Answer

electron transfer to a less mobile energy level

Answer

avalanche breakdown with the high voltage gradient

Answer

tunnelling across the junction

Answer

electron domains forming at the junction

Question 6

The negative resistance in a tunnel diode is

Accepted Answer

available between peak and valley points

Answer

maximum at the peak point of the characteristics

Answer

maximum at valley point

Answer

none of these

Question 7

When current through a zener diode increases by a facto of 2, the voltage across its terminals

Accepted Answer

remains unaltered

Answer

is halved

Answer

gets doubled too

Answer

none of these

Question 8

An avalanche diode

Accepted Answer

is usually operated in the reverse?biased mode only

Answer

is the same as the zener diode

Answer

is operated in the forward?biased mode only

Answer

none of these

Question 9

The dynamic impedance of a zener diode

Accepted Answer

decreases with increase in current through it

Answer

increases with increase in current through it

Answer

is independent of current passing through it

Answer

none of these