In this lab you will be dropping magnets in the copper tube. You will observe magnet falling with constant velocity due to currents induced in the tube. We model the tube as a stack of thin conducting rings to estimate the terminal velocity of the falling magnet. Assume the magnetic dipole moment of the dropping magnet is directed downward as shown in Figure M.1. What is the direction of induced current in the element of the tube (the ring) located below moving magnet (clockwise or counterclockwise as viewed from the top)? What is the direction of induced current in the ring located above the magnet?
Imaging the tube is now replaced with a long solenoid which also consists of many conducting but isolated rings of copper wire connected in series. Assume we connect the ends of the wire in the solenoid (see the Figure) to create a closed circuit. Assume the thickness of the wire is comparable with the thickness of the tube in our lab experiment. Imaging you drop the magnet in such a long solenoid. Do you expect the magnet to fall with constant (albeit different) velocity in a similar manner as in the tube? Provide qualitative (no calculations) explanation.
