There is a bar magnent falling through a metal ring. The first metal ring is solid all the way around but in the second metal ring it has been cut through. Why is the motion in the magnent with the solid metal ring ed when the magnent is above the ring and below the ring. What induced currents appear in the ring? Why is motion unaffected in the ring in part 2?

In the first case, the changing matgnetic field trhough the ring allows a current to flow in the ring which opposes the change in magnetic field, creating in essence a magnet with reversed polarity to oppose motion of the bar magnet. In the second case (open ring), this does not happen because a ring current cannot flow.

smd

The motion of the magnet in the two scenarios you described is affected by principles related to electromagnetic induction. To understand why, let's break down each scenario and examine the induced currents:

Scenario 1: Solid Metal Ring
When the magnet falls through the solid metal ring, the motion of the magnet becomes ed, meaning it slows down. This is due to the phenomenon of electromagnetic induction. As the magnet falls through the solid metal ring, the changing magnetic field generated by the magnet induces currents within the metal ring.

According to Faraday's law of electromagnetic induction, a changing magnetic field induces an electromotive force (EMF) or voltage in a nearby conductor. In this case, the solid metal ring acts as a conductor. As the magnet falls, the magnetic field passing through the ring changes, creating currents within the metal itself.

The direction of the induced currents can be determined using Lenz's law, which states that the induced current opposes the change that produced it. Therefore, as the magnet falls through the solid metal ring, the induced currents flow in a way that exerts a magnetic field that opposes the motion of the falling magnet. This opposing magnetic field creates a drag force on the magnet's motion, retarding its speed.

Scenario 2: Cut Metal Ring
In the second scenario, where the metal ring is cut through, the motion of the magnet remains unaffected. This is because the cut interrupts the path of the induced currents, preventing them from flowing consistently.

When the magnet falls through the cut metal ring, the changing magnetic field still induces currents within the metal. However, these induced currents cannot form a complete loop within the ring due to the cut. As a result, the induced currents are disrupted and do not create a significant opposing magnetic field that would affect the motion of the magnet.

In summary, the motion of the magnet is ed when falling through the solid metal ring due to the induced currents created by the changing magnetic field. These induced currents create a magnetic field that opposes the magnet's motion, resulting in a drag force. However, in the cut metal ring scenario, the motion remains unaffected since the cut interrupts the path of the induced currents, preventing them from generating a significant opposing magnetic field.