If a small amount of antimony (Sb) is added to germanium crystal,______.

(a)

it becomes a p-type semiconductor

(b)

the antimony becomes an acceptor atom

(c)

there will be more free electrons than hole in the semiconductor

(d)

its resistance is increased

When a transistor is fully switched on, it is said to be _________________.

(a)

Shorted

(b)

Saturated

(c)

Cut-off

(d)

Open

The electrical series circuit in digital form is

(a)

AND

(b)

OR

(c)

NOR

(d)

NAND

By adding _________ impurity in intrinsic semi conductor, p type semiconductor is made. Charge of these p type semiconductor is ____________

(a)

Trivalent, neutral

(b)

Pentaralent, neutral

(c)

Pentavalent, positive

(d)

Trivalent, negative

The behaviour of Ge as semi-conductor is due to width of ___________.

(a)

conduction band being large

(b)

forbidden band being small

(c)

conduction band being small

(d)

forbidden band being small and narrow

How many free electrons does a p-type semiconductor contain?

(a)

Many

(b)

None

(c)

only those produced

(d)

same number as holes by thermal energy

To obtain a p-type germanium semiconductor, it must be doped with _____________.

(a)

Indium

(b)

phosphorus

(c)

arsenic

(d)

antimony

Doping of a semiconductor generally changes resistivity as follows ________________.

(a)

increases

(b)

decreases

(c)

does not alter

(d)

may increase

Current gain in common emitter configuration is more than I because _______________.

(a)

IC < IE

(b)

IC < IB

(c)

IE > IB

(d)

IC > IE

Zener diode is used for _________________.

(a)

rectification

(b)

amplification

(c)

producing oscillation

(d)

stablisation

If the distance between the conduction band and valence band is leV, then this combination is _______________.

(a)

semiconductor

(b)

metal

(c)

insulator

(d)

conductor

In which of the configuration of transistors the voltage gain is the highest?

(a)

common collector

(b)

common base

(c)

common emitter

(d)

same in all the three

Vacant energy levels are called _________

(a)

valence level

(b)

core level

(c)

conduction levels

(d)

compound level

The forbidden energy gap is largest in ______________.

(a)

conductor

(b)

metals

(c)

semiconductor

(d)

insulators

When a pentavalent impurity is added to a pure semi conductor we get ___________ semiconductor.

(a)

N-type

(b)

P-type

(c)

A-type

(d)

B-type

Zener breakdown is mainly due to ________

(a)

collision

(b)

breaking of covalent bonds

(c)

doping

(d)

recombination

In the output characteristics, the ohmic region is called ______

(a)

saturation region

(b)

cut-off region

(c)

active region

(d)

breakdown region

If the output is high for anyone of all of the inputs then it is ___________ gate

(a)

a NOT

(b)

an AND

(c)

an OR

(d)

a NOR

The collector-base junction of a transistor offers _________ resistance to current

(a)

low

(b)

high

(c)

zero

(d)

moderate

In the output characteristics curve of an NPN transistor, _________ is about to be a constant near knee point.

(a)

I_C

(b)

I_B

(c)

I_E

(d)

V_CC