1. Relative permeability of vacuum is ?

1

1 W/m

1/4?

4? x 10-7 H/m

Answer: 1

Explanation:


2. ln order to minimise loss due to hysteresis, the magnetic material should have ?

high resistivity

low hysteresis coefficient

large B-H loop area

high retentivity

Answer: low hysteresis co-efficient

Explanation:


3. While comparing magnetic and electric circuits, the flux of magnetic circuit is compared with which parameter of electrical circuit ?

E.m.f.

Current

Current density

Conductivity

Answer: Current

Explanation:


4. The initial rate of rise of current through a coil of inductance 1O H when suddenly connected to a D.C. supply of 200 V is ........... A/s ?

60

20

0.05

600

Answer: 20

Explanation: