Question

An e.m.f. is produced in a coil, which is not connected to an external voltage source. This can be due to

• A. The coil being in a time varying magnetic field
• B. The coil moving in a tie varying magnetic field
• C. The coil moving in a constant magnetic field
• D. The coil is stationary in external spatially varying magnetic field, which does not change with time

Answer 1

Answer: (A), (B), (C)

The coil being in a time varying magnetic field
The coil moving in a tie varying magnetic field
The coil moving in a constant magnetic field

$e.m.f.$ produced in coil due to change in magnetic flux with time in option (a), (b) and (c).

But in part (d) magnetic field does not change with time although varying magnetic field but rate of change of magnetic field does not change so rejects the option (d).

So answers are (a) (b) and (c).