Materials And Components MCQ Questions & Answers

21

In van der walls crystals, there exists a high degree of stability of the outer electron shell.

A) True B) False

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

22

On the basis of the type of chemical bonds, solids may be classified into

A) Ionic crystals B) Ionic and valence crystals C) Ionic crystal, valence crystals and metals D) Ionic crystals, valence crystals, metal and vander wall crystals

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

23

Which of the following are true for relative dielectric constant?
1. It is dimensionless.
2. It is equal to 1 for vacuum.
3. It is equal to 1 for all substances.

A) 1 and 2 only B) 2 and 3 only C) 1 and 3 only D) 1, 2 and 3

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

24

In an intrinsic semiconductor, at a given temperature T

A) The number of electrons-hole pairs generated per second due to thermal motion are equal to the number of electron-hole pairs lost per second due to recombination B) The number of electron-hole pairs generated per second due to thermal motion is always less than the number of electron-hole pairs lost per second due to recombination C) The number of electron hole pairs generated per second due to thermal motion is always more than the number of electron-hole pairs lost per second due to recombination D) Any of the above

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

25

The resistance of a photoconductor

A) Increases with increase in light intensity B) Decreases with increase in light intensity C) May increase or decrease with increase in light intensity D) Remains constant

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

26

Electrical contact materials used in switches, brushes, relay must possess

A) High thermal conductivity and high melting point B) Low thermal conductivity and low melting pointL C) High thermal conductivity and low melting point D) Low thermal conductivity and high melting point

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

27

The merger of hole and free electron is called

A) Covalent bonding B) Recombination C) Thermal energy D) Free electrons

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

28

Ferrimagnetic materials have anti parallel orientation of equal moments of permanent dipoles.

A) True B) False

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

29

In a metal, the valence electrons

A) Are not shared B) Are shared only between neighbouring atoms C) Are shared by all atoms D) Either B or C

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

30

Wood is a diamagnetic material.

A) True B) False

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

Materials And Components MCQ Questions & Answers | ECE