Electronic Devices and Communication MCQ with Answers

1) basic materials used in the present solid state electronic devices like diode, transistor, ICs, etc are

Answer is:

conductors

Explanation:

metals are used as basic material in present solid state device.

2) In the case of metals the valence and conduction bands have

Answer is:

overlap, energy gap =0

Explanation:

In the case of metals the valence and conduction bands have no overlap, energy gap is small

3) In the case of semiconductors the valence and conduction bands have

Answer is:

no overlap, energy gap is small

Explanation:

In the case of semiconductors the valence and conduction bands have no overlap, energy gap is small

4) Hole is a vacancy or lack of an electron and can travel through the material. It can

Answer is:

only serves as a vacant spot and cannot conduct current

Explanation:

Hole is a vacancy or lack of an electron and can travel through the material. It can only serves as a vacant spot and cannot conduct current

5) In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always present

Answer is:

such that number of electrons is greater than the number of holes

Explanation:

An?intrinsic semiconductor?is an undoped semiconductor. This means that holes in the valence band are vacancies created by electrons that have been thermally excited to the conduction band, as opposed to doped?semiconductors?where holes or electrons are supplied by a ?foreign? atom acting as an impurity.