The current in a solenoid of 240 turns, having a length of 12 cm and a radius of 2 cm, changes at a rate of0.8As−1 Find the emf induced in it.
H=μ0n2Adi6didt=4π×10−7×(240)2×π×(2×10−2)212×10−2×0.8=4π×(24)2×π×4×812×10−8=60577.3824×10−8=6×10−4V.
The current in a long solenoid of radius R and having n turns per unit length is given i=i0sinωt. A coil having N turns is wound around it near the centre. Find (a) the induced emf in the coil and (b) the mutual inductance between the solenoid and the coil.