What is electromagnetic damping?

(N/A) Electromagnetic damping is a phenomenon where the motion of a conductor (like a magnet moving near a metal) is retarded by the eddy currents induced within the conductor.
To demonstrate this,take two hollow thin cylindrical pipes of equal internal diameters made of aluminium and $PVC$ respectively. Fix them vertically with clamps on retort stands.
Take a small cylindrical magnet having a diameter slightly smaller than the inner diameter of the pipes and drop it through each pipe such that the magnet does not touch the sides.
You will observe that the magnet dropped through the $PVC$ pipe takes the same time to fall as it would in free space,because $PVC$ is an insulator and no eddy currents are generated.
However,the magnet takes a much longer time to fall through the aluminium pipe. This is because as the magnet falls,the changing magnetic flux induces eddy currents in the conducting aluminium pipe. According to Lenz's Law,these eddy currents create a magnetic field that opposes the motion of the magnet.
This retarding force,caused by the interaction between the magnet and the eddy currents,is known as electromagnetic damping.