Question

A short magnet is moved along the axis of a conducting loop. Show that the loop repels the magnet if the magnet is approaching the loop and attracts the magnet if it is going away from the loop.

Answer 1

Explanation:

To show: The loop repels the magnet if the magnet is approaching the loop and attracts the magnet if it is going away from the loop.

• Consider the above situation where a magnet is driven toward a circular circle that conducts.

• The magnet's Pole lies to the north Circle.

• As the magnet comes closer to the coil, the magnetic field decreases; therefore, flux increases through the loop.

• The position of induced current is such, By the Law of Lenz, that it Disputes the magnetic area that has caused it.

• The induced current thus generates a magnetic field in the opposite direction to the initial one; hence the magnet is repelled by the coil.

• In comparison, when the magnet enters the ring, the magnetic area decreases. Then flux decreases through the loop.  

• The induced current generates a magnetic field in the opposite way of the initial field By the Law of Lenz; thus the loop attracts the magnet.