question_answer

A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current \[I={{I}_{0}}\cos (\omega t).\]The emf induced in the smaller inner loop is nearly? [JEE Online 08-04-2017]

A) \[\pi {{\mu }_{0}}{{I}_{0}}\frac{{{a}^{2}}}{b}\omega \sin (\omega t)\]

B) \[\frac{\pi {{\mu }_{0}}{{I}_{0}}}{2}.\frac{{{a}^{2}}}{b}\omega \cos (\omega t)\]

C) \[\frac{\pi {{\mu }_{0}}{{I}_{0}}{{b}^{2}}}{a}\omega \cos (\omega t)\]

D) \[\frac{\pi {{\mu }_{0}}{{I}_{0}}}{2}.\frac{{{a}^{2}}}{b}\omega \sin (\omega t)\]