Electronics and Communication Engineering - Materials and Components

21. 

Which element exhibits the property of inertia?

A. Resistance
B. Capacitance
C. Inductance
D. Both resistance and inductance

Answer: Option C

Explanation:

Inductance opposes rise and decay of current. Hence it has the property of inertia.


22. 

For a permanent magnetic material

A. the residual induction and coercive field should be large
B. the residual induction and coercive field should be small
C. area of hysteresis loop should be small
D. initial relative permeability should be high

Answer: Option A

Explanation:

Materials suitable for permanent magnet have large hysteresis loop.

Hence residual and coercive field are large.


23. 

In a coaxial cable, braided copper is used for

A. conductor
B. shield
C. dielectric
D. jacket

Answer: Option B

Explanation:

Braided material is used for shield.


24. 

The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.

A. True
B. False

Answer: Option B

Explanation:

Hysteresis phenomenon exists below ferromagnetic curie temperature.


25. 

Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.

Reason (R): For diamagnetic as well as paramagnetic materials, μr is nearly equal to 1.

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 A

Explanation:

Magnetic susceptibility = (μr - 1)H.

For diamagnetic and paramagnetic materials magnetic susceptibility is very very small and μr = 1.