A wire of length L is wound on a spherical form, and a current I is passed through it. The coil is then placed in a uniform magnetic field of induction B. Find the number of turns so that the torque on it to be maximum.

Step-by-step solution

Torque = NABI Max Torque = NABI for =90^ For a coil of given length L Radius = L / 2 N Area = ( radius )= L ^2 4 ^2 ~N ^2 Torque = NBI L ^2 4 ^2 ~N ^2 Torque l N Smallest value of N for Torque is n =1