A small square loop of side 'a' and one turn is placed inside a larger square loop of side b and one turn ( b ≫ a ). The two loops are coplanar with…

A small square loop of side 'a' and one turn is placed inside a larger square loop of side b and one turn ( $\displaystyle \mathrm{b} \gg \mathrm{a}$ ). The two loops are coplanar with their centres coinciding. If a current I is passed in the square loop of side ' $\displaystyle b$ ', then the coefficient of mutual inductance between the two loops is :