A rectangular conducting loop B has its side lengths equal to b and `a ( lt lt b)`. In the plane of the loop there is another very small loop A in shape of a square of side length x. Loop A is placed symmetrically with respect to B with its centre at a distance a from one of its longer side (see Figure). There is a current (i) in loop A which is made to increase at a constant rate of `(di)/(dt) = alpha As^(–1)`. Calculate the emf induced in the bigger loop.

Answer

`(mu_(0)a alpha)/(4pi)`