Text: 1. Experiment Take a permanent magnet and put it on table. Than take a metallic disk. Any conducting disk is fine. Attached this disk to some sort of rotating mechanism. You will need some sort of axes thru the centre of disk. I usually do this by attaching a metallic disk to some stick or short round bar with the glue. With for the glue to dry. Then put one end of the bar or stick in drilling machine. Now, you can rotate the disk around its axis. Put the disk over the magnet, so that the axis of magnetic field of permanent magnet and the axis of rotation of disk coincide. Rotate the disk over the magnet and measure the voltage between the rim and the axis of the disk. Induced voltage will be detected. 2. Experiment Now you have to reverse rotating object. In this experiment you will have to rotate the magnet and have the disk stationary. Prepare the magnet as you did prepare the disk in experiment 1. Then put the magnet over disk so that the axis of magnetic field of permanent magnet and the axis of disk coincide. Now rotate the disk. One would expect that the induced voltage would be measured. Yet it is not so. No voltage is induced in the disk. Even that you apparently have a relative motion between the magnetic field and the conductive disk. 3. Experiment Let us make third and last experiment. Glue together magnet and conductive disk. Of course the axis have to coincide. And rotate them both. An induced voltage is measured between rim of the disc and it's axis. Yet there is no relative motion between magnet and the disk.

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