Question

An electric current is induced in a circuit when:

• A. a magnet is brought close to a wire.
• B. a magnet is kept close to a wire.
• C. a magnet is taken away from a wire.
• D. a magnet is kept far from a wire.

Answer 1

Answer: (A), (C)

The correct options are
A

a magnet is brought close to a wire.

C

a magnet is taken away from a wire.

When the number of magnetic field lines interacting with the wire changes, a current is induced in the wire. Hence, when a magnet is brought close to a wire or taken away from a wire, a current is induced as the number of magnetic field lines interacting with the wire changes. When a magnet is kept close to a wire or kept far from a wire, the number of field lines interacting will be constant. Hence, no current is induced in the wire.