A solenoidal coil has 50 turns per centimetre along its length and a cross-sectional area of 4 × 10^(-4) m^2….

Q: A solenoidal coil has 50 turns per centimetre along its length and a cross-sectional area of 4 × 10^(-4) m^2. 200 turns of another wire is wound round the first solenoid co-axially. The two coils are electricity insulated from each other. Calculate the mutual inductance between the two coils.

Sol: n1 = 50 turns per cm = 5000 turns per metre

n2 l = 200 , A = 4 × 10-4 m2 ;

M = μ0 n1 (n2 l)A

= 4π × 10-7 × 5000 × 200 × 4 × 10-4 m2 H

= 5.03 × 10-4 H