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…

A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius $\displaystyle b$. The two loops are in the same plane. The outer loop of radius b carries an alternating current $\displaystyle \mathrm{I}=\mathrm{I}_{\mathrm{o}} \cos (\omega \mathrm{t})$. The emf induced in the smaller inner loop is nearly :