A metallic ring is dropped down, keeping its plane perplendicular to a constant and horizontal magnetic field. The ring enters the region of magnetic field at t=0 and completely emerges out at t=T sec . The current in the ring varies as

Step-by-step solution

1. When the ring is just entering the magnetic field, emf is induced and the current flows in one direction. 2. When the whole ring is surrounding the flux inside, there is no change in the flux. Induced emf =0 , current is zero. 3. When the ring just goes out of the region of flux, a pulse of current is produced which is opposite to that of 1 given above. (2) is the only figure that describes this.