Question

Consider the situation as shown in the figure. If the current $I$ in long straight conducting wire XY is increased at a steady rate then the induced e.m.f.'s in loops A and B will be

• A. clockwise in A, anti clockwise in B
• B. anti clockwise in A, clockwise in B
• C. clockwise in both A and B
• D. anti clockwise in both A and B

Answer 1

The correct option is A clockwise in A, anti clockwise in B

By right hand grip rule, we can deduce that the magnetic field due to the current carrying wire will be such that it comes out of the plane on the side of loop A and goes into the plane on the side of loop B.
As the current increases, the magnitude of this field will increase thus increasing the flux associated with these loops. By Lenz's Law, the current in the rings will be induced in such a manner that this change in flux will be opposed i.e. the field due to loop A will go inside the plane and that due to loop B will come out of the plane.
From right hand grip rule, we can say that for the loops to produce such a magnetic field, the current will flow clockwise in loop A and anti clockwise in loop B