When a carpet is beaten with a stick, the dust comes out of it ? Explain.

A metal disc is winging freely between the poles of an electromagnet, as shown in the figure. When the electromagnet is switched on, the disc comes to rest after a few oscillations. Explain why eddy currents are induced in the metal disc.

What happens when a strong current is passed through a semiconductor? Explain.

Water comes out of a cell when it is placed in:

Why does a person not able to see for some time when he comes out of a well lighted room at night or enters a dark room at day time?