Posted by H on .
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 retarded 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.