(N/A) When a small magnet is allowed to fall through a long vertical aluminium pipe,the magnetic flux linked with the pipe changes as the magnet moves. This change in magnetic flux induces eddy currents in the pipe walls.
According to Lenz's law,these eddy currents oppose the motion of the falling magnet. The magnetic field produced by the eddy currents exerts an upward force on the magnet,which opposes its downward acceleration due to gravity. As a result,the magnet falls with a reduced acceleration,and its terminal velocity becomes much smaller than the acceleration due to gravity $(g)$.
If the pipe is cut along its length,the path for the eddy currents is broken,and the magnet will fall with an acceleration close to $g$.