Electronics and Communication Engineering - Materials and Components

26. 

The attraction between the nucleus and valence electron of copper atom is

A. zero
B. weak
C. strong
D. either zero or strong

Answer: Option B

Explanation:

The valence electron, in copper atom, can be easily detached from nucleus.


27. 

If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then

A. the majority carrier density is doubled
B. the minority carrier density is doubled
C. the minority carrier density becomes 4 times the original value
D. both the majority and minority carrier densities double

Answer: Option D

Explanation:

As the intrinsic carrier concentration is doubled, the concentration of both electrons and holes is doubled.


28. 

There is no hysteresis phenomenon is any dielectric material.

A. True
B. False

Answer: Option B

Explanation:

Hysteresis phenomenon exists in dielectic materials.


29. 

The units of μ0 and μr are

A. H/m for both
B. H/m for μr and no units for μ0
C. H/m for μ0 and no units for μr
D. Wb/m for μ0 and no units for μr

Answer: Option C

Explanation:

μr is only a numeric.


30. 

In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.

A. True
B. False

Answer: Option A

Explanation:

In a metal valence electrons are shared by all atoms.