Electronics and Communication Engineering - Materials and Components

11. 

The equation D = ∈0r E refers only to isotropic materials.

A. True
B. False

Answer: Option A

Explanation:

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12. 

When a ferromagnetic substance is magnetised there are small changes in dimensions. This phenomenon is called

A. hysteresis
B. magnetostriction
C. diamagnetism
D. dipolar relaxation

Answer: Option B

Explanation:

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13. 

Assertion (A): In some materials, ∈r is independent of temperature while in others, ∈r depends on temperature.

Reason (R): If permanent dipoles are absent, ∈r varies with temperature.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

Answer: Option C

Explanation:

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14. 

An electron in a homogeneous magnetic field and having velocity perpendicular to the direction of field moves

A. perpendicular to the field
B. along the field
C. along a straight line inclined at 45° to field
D. in a circular path

Answer: Option D

Explanation:

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15. 

Spontaneous polarization occurs in ferroelectric materials.

A. True
B. False

Answer: Option A

Explanation:

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