question_answer

A conducting wire frame is placed in a magnetic field which is directed into the paper. The magnetic field is increasing at a constant rate. The directions of induced current in wires AB and CD are

A)            B to A and D to C              

B)            A to B and C to D              

C)            A to B and D to C              

D)            B to A and C to D

Correct Answer: A

Solution :

                   Inward magnetic field (´) increasing. Therefore, induced current in both the loops should be anticlockwise. But as the area of loop on right side is more, induced emf in this will be more compared to the left side loop \[\left( e=-\frac{d\varphi }{dt}=-A.\frac{dB}{dt} \right)\]. Therefore net current in the complete loop will be in a direction shown below. Hence only option (a) is correct.