Question

Which actions are ways to manipulate the magnet and wire loop in order to induce a current? Check all that apply.

Move the magnet forward.
Move the loop away from the magnet.
Place the loop right next to the magnet, both stationary.
Move the loop sideways.
Move the magnet and loop in the same direction, at the same speed, at the same time.
Rotate the loop in place.

Answer 1

Correct choices:
- Move the magnet forward.
- Move the loop away from the magnet.
- Move the loop sideways.
- Rotate the loop in place.

Reason: Faraday’s law says an induced emf (current) appears when the magnetic flux through the loop changes. Moving the magnet toward or away from the loop changes the field strength through the loop; moving the loop sideways across a nonuniform field changes the flux too; rotating the loop changes the angle between the loop area and the field. If both are stationary, or if you move the magnet and loop together with no change in their relative position, the flux does not change and no current is induced.