Notes

Mutual Inductance between Two Coils…

Mutual Inductance between Two Coils –
(i)If two coil (1 and 2) also called primary and secondary coils are placed close to each other (maximum coupling), then mutual inductance between them
[M = B₁ N₁ N₂ A₂/I₁]
(ii) If the coils are two concentric coplaner circular coils, then mutual inductance between them
[M = πμ₀ N₁ N₂ r²/2R]
⇒ M ∝ r²/R
(iii) For two solenoids tightly wound to each other as shown below Magnetic field inside the primary solenoid,
B₁ = μ₀ n₁ I₁ (n₁ = N₁/I)
Thus, [M = μ₀ N₁ N₂ A/l]