If the coils of an electromagnet are placed inside a set of secondary coils, what has to happen to create a current in the secondary coils? a.
The current in the electromagnet must be zero.

b.
The current in the electromagnet must be constant (but not zero).

c.
The current in the electromagnet must be constant (or zero).

d.
The current in the electromagnetic must be increasing or decreasing - changing and not steady.