Question

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area A = 10 cm² and length l = 20 cm. If one of the solenoids has 300 turns and the other 400 turns, their mutual-inductance is (µ₀ = 4p × 10^–7 T m A^–1)

• A. 2.4 p × 10^–5 H
• B. 4.8 p × 10^–4 H
• C. 4.8 p × 10^–5 H
• D. 2.4 p × 10^–4 H

Answer 1

Answer: (D)

2.4 p × 10^–4 H

Answer 2

M = k $\sqrt { \mathrm { L } _ { 1 } \mathrm {~L} _ { 2 } }$

considering ideal coupling

M = $\frac { \mu _ { 0 } \mathrm {~A} } { \ell }$N₁N₂ = 2.4 p × 10^–4