A long solenoid of 15 turns per cm has a small loop area of `2 cm^2` placed inside normal to the axis of the solenoid changes steadily from 2A to 4A in 0.1s. Calculate emf induced in the loop.

A circular coil of 100 turns has radius 4 cm. It is placed with its plane perpendicular to a magnetic field of 3T. If the magnetic field, reduces to 1 T in 0.2s, calculate the e.m.f induced in the coil.