Question

The coefficient of self-inductance of a solenoid is 0.20 mH. If a core of soft iron of relative permeability 900 is inserted, then the coefficient of self-inductance will become nearly ______

Options

• 1.8 mH

• 180 mH

• 0.018 mH

• 0.18 mH

Answer 1

The coefficient of self-inductance of a solenoid is 0.20 mH. If a core of soft iron of relative permeability 900 is inserted, then the coefficient of self-inductance will become nearly 180 mH.

Explanation:

L = μ₀nI

∴ `"L"_2/"L"_1 = mu/mu_0` ...........(∵ n and I are same)

∴ L₂ = μ_rL₁ = 900 × 0.20 = 180 mH