A circular copper disc 10cm in radius rotates at 20 pie rad/s about an axis through its centre and perpendicular to the disc. a uniform magnetic field of 0.2 T acts perpendicular to the disc. 

         (a) calculate the potential difference developed between the axis of the disc and the rim.
         (b) what is the induced current of the resistance of the disc is 2 ohm.

A coil Q is connected to low voltage bulb B and placed near another coil P as shown in fig. give reasons to explain the following observations.
(a) the bulb 'B' lights.
(b) Bulb gets dimmer if the coil Q is moved towards left.

fig. below shows planar loops of different shapes moving out of or into a region of a magnetic field which is directed normal to the plane of the loop away from the reader. determine the direction of induced current in each loop using lenz's rule.

ELECTRIC POTENTIAL AT ANY POINT DUE TO AN ELECTRIC DIPOLE...........

MAGNETIC FIELD DUE TO TORROID..........