Question

4.3.2 test (cst): electromagnets
question 9 of 20
a permanent magnet is placed in a coil of wire. if there is no electric current in the wire, which statement must be true?
a. the magnet is shorter than the coil of wire.
b. the magnet is longer than the coil of wire.
c. the magnet is moving relative to the wire.
d. the magnet is not moving relative to the wire.

Explanation:

According to Faraday's law of electromagnetic induction, an electric current is induced in a coil when there is a relative motion between the magnet and the coil (which changes the magnetic flux through the coil). If there is no current, it means there is no change in magnetic flux, which implies no relative motion.

Answer:

D. The magnet is not moving relative to the wire.