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Electronics and Communication Engineering - Electronic Devices and Circuits

Exercise : Electronic Devices and Circuits - Section 4
41.

Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases.

Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive device.

Both A and R are true and R is correct explanation of A
Both A and R are true but R is not a correct explanation of A
A is true but R is false
A is false but R is true
Answer: Option
Explanation:

When exposed to light bulk resistance decreases. Therefore, A is wrong.

42.
As comparated to an ordinary p-n diode, the extent of impurity atoms in a tunnel diode
is more
is less
may be more or less
is almost the same
Answer: Option
Explanation:

Tunnel diode has heavily doped p and n regions.

43.
In active filter circuits, inductances are avoided mainly because they
are always associated with some resistance
are bulky and unsuitable for miniaturisation
are non-linear in nature
saturate quickly
Answer: Option
Explanation:

In active circuit, Inductors are used by Op-Amp resistors and capacitor instead of simple inductor.

44.
When a p-n-p transistor is operating in active region, the current in the n region is due to
only holes
only electrons
mainly holes
mainly electrons
Answer: Option
Explanation:

Since emitter is p-type, emitter current is mainly due to holes. This current diffuses through the base.

45.
In a JFET
drain current is very nearly equal to source current
drain current is much less than source current
drain current may be equal to or less than source current
drain current may be even more than source current
Answer: Option
Explanation:

Since gate current is very small. ID and Is are almost equal.

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