Question

Use Lenz's law to determine the direction of induced current in the situations described by Fig.(a) A wire of irregular shape turning into a circular shape;(b) A circular loop being deformed into a narrow straight wire.

Answer 1

According to the Lenz's law, the current induced will oppose the change in flux through the loop.

(a) Since the area of loop is increasing with time, the flux through it will increase and hence the current induced will be such that its magnetic field produced is in the opposite direction.

Hence according to right hand rule, the current will be in clockwise direction

(b) Since the area of loop is decreasing with time, the flux through it will decrease and hence the current induced will be such that its magnetic field produced is in the same direction to maintain the flux right hand rule, Direction of current, - adcb