Question

Two coils are placed near each other. When the current in one coil is changed at the rate of 5 A/s, an emf of 2 mV is induced in the other. The mutual inductance of the two coils is ______.

Options

• 0.4 mH

• 2.5 mH

• 10 mH

• 2.5 H

Answer 1

Two coils are placed near each other. When the current in one coil is changed at the rate of 5 A/s, an emf of 2 mV is induced in the other. The mutual inductance of the two coils is 0.4 mH.

Explanation:

By Mutual Inductance

`epsilon_2 = -M(dI)/(dt)`

2 × 10⁻³ = −M(5)

M = −0.4 mH

The negative sign shows that the mutual inductance is opposite to the induced emf.