Two coils are placed near each other. When the current in one coil is changed at the rate of $5 \mathrm{~A} / \mathrm{s}$, an emf of 2 mV is induced in the other. The mutual inductance of the two coils is

A square shaped coil of side $$10 \mathrm{~cm}$$, having 100 turns is placed perpendicular to a magnetic field which is increasing at $$1 \mathrm{~T} / \mathrm{s}$$. The induced emf in the coil is