Electronics and Communication Engineering - Materials and Components

46. 

If a piece of wood is placed in a magnetic field

A. the magnetic field will not be affected
B. the magnetic lines of force will bend towards the piece
C. the magnetic lines of force will bend away from the piece
D. the flux may increase or decrease

Answer: Option A

Explanation:

Wood is non-magnetic.


47. 

The apparent capacitance at a high angular frequency ω of an air cored capacitor having capacitance C and inductance L is given by

A.
B.
C.
D.

Answer: Option B

Explanation:

The combination can be represented as L and C in series.

.

Therefore, .


48. 

The number of valence electrons in donor impurity are

A. 5
B. 4
C. 3
D. 1

Answer: Option A

Explanation:

Donor impurity has 5 valence electrons (while silicon has 4 valence electrons).

Hence donor impurity can donate electrons.


49. 

In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.

A. True
B. False

Answer: Option A

Explanation:

Sharing of valence electons is a characteristic of true valence crystal.


50. 

Which of the following are donor impurities?

  1. Gold
  2. Phosphorus
  3. Boron
  4. Antimony
  5. Arsenic
  6. Induim
Select the correct answer using the following codes

A. 1, 2, 3
B. 1, 2, 4, 6
C. 3, 4, 5, 6
D. 2, 4, 5

Answer: Option D

Explanation:

Donor impurities have five valence electrons.


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