Electronic Devices And Circuits

Exercise: Electronic Devices And Circuits

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: A

Tunnel diode has heavily doped p and n regions.

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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: D

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

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In degenerate p type semiconductor material, the Fermi level,

is in the valence band

is in conduction band

is at the centre in between valence and conduction bands

is very near conduction band

Answer: A

This is due to heavy doping.

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Assertion (A): The amount of photoelectric emission depends on the intensity of incident light.

Reason (R): Photo electric emission can occur only if frequency of incident light is less than threshold frequency.

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: C

Photo electric emission occurs only if frequency is higher than threshold frequency thus R is wrong.

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Which of the following devices has substrate?

JFET

Depletion Type MOSFET

Enhancement type MOSFET

Both (b) and (c)

Answer: D

All MOSFETs have substrate.

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