Electronic Devices and Circuits Questions & Answers - Page 6

26.

Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down.

Reason (R): High reverse voltage causes Avalanche effect.

A.

Both A and R are true and R is correct explanation of A

B.

Both A and R are true but R is not a correct explanation of A

C.

A is true but R is false

D.

A is false but R is true

Correct answer is A

Avalanche breakdown occurs at high reverse voltage.

27.

As compared to an ordinary semiconductor diode, a Schottky diode

A.

has lower cut in voltage

B.

has higher cut in voltage

C.

lower reverse saturation current

D.

both (b) and (c)

Correct answer is A

Cut in voltage in Schottky diode is about 0.3 V as compared to 0.7 V in ordinary semiconductor diode.

29.

Recombination produces new electron-hole pairs

A.

True

B.

False

C.

Cannot say

D.

It depends

Correct answer is B

Due to recombination, the number of electron-hole pairs is reduced.

30.

In a bipolar transistor, the barrier potential is

A.

0

B.

a total of 0.7 V

C.

0.7 V across each depletion layer

D.

0.35 V

Correct answer is C

Since there are two p-n junctions, there are two depletion layers and 0.7 V across each layer.