MCQs on Semiconductor Physics

Intrinsic semiconductors are:

• Pure semiconductors

• Doped with impurities

• Insulators

• Conductors

The Fermi level in intrinsic semiconductors lies:

• Near the conduction band

• In the middle of the energy gap

• Near the valence band

• Outside the band gap

Electrons and holes recombine in semiconductors releasing:

• Sound energy

• Light

• Magnetic energy

• Chemical energy

Mobility of electrons is defined as:

• Velocity × electric field

• Current density / electric field

• Drift velocity / electric field

• Charge × resistance

Mobility of charge carriers depends on

• temperature

• nature of charge carriers

• purity of substance

• none of them

Drift current occurs due to:

• Concentration gradient

• Electric field

• Temperature gradient

• Photon absorption

In a p-n junction, the depletion region has:

• Free charge carriers

• Ions only

• Holes only

• Electrons only

The potential barrier in a silicon diode is approximately:

• 0.1 V

• 0.3 V

• 0.5 V

• 0.7 V

at absolute zero, when energy state is grater than fermi energy level then probability energy state E to be filled with electron will be

• 0

• 1

• 1/2

• 1/4

A Tunnel diode is known for:

• Negative resistance

• High forward voltage

• Low mobility

• High capacitance