A magnet, with its south pole pointed downwards, is falling down directly above a wire loop. As the magnet approaches the wire loop (before it passes through the loop),

Question

A magnet, with its south pole pointed downwards, is falling down directly above a wire loop. As the magnet approaches the wire loop (before it passes through the loop),

a) an induced current flows through the wire loop, in a clockwise orientation (as seen from above).

b) an induced current flows through the wire loop, in a clockwise orientation (as seen from above).

c) no current flows through the wire loop

Answer 1

A loop of wire with current traveling through it acts as an electromagnet. If the current is clockwise (as seen from above), the electromagnet is oriented with its south pole up. If the current is counterclockwise (as seen from above), the electromagnet is oriented with its north pole up.

Currents are induced in loops of wire when the magnetic field through that loop is changing. You can create those changes by moving a magnet around near the loop, or dropping the magnet through the loop.

Now the key point: The loop of wire always "wants" to become an electromagnet that resists the change in the magnetic field.

So if you drop a magnet with its south pole facing downwards through a loop of wire, the loop of wire becomes an electromagnet with its south pole facing upward. In order for this to happen, there must be a clockwise current through the loop.