Question

Two coils of self inductance $4\text{H}$ and $16\text{H}$ are wound on the same iron core. The coefficient of mutual inductance for them will be

• A. $8\text{H}$
• B. $10\text{H}$
• C. $20\text{H}$
• D. $64\text{H}$

Answer 1

The correct option is A $8\text{H}$

Mutual inductance is given by the formula,

$M=K\sqrt{L_1{L}_2}$

Here,

$K=1$

Since, the inductors are wound on the same iron core.

$\therefore M=\sqrt{4\times 16}=8\text{H}$

Hence, option $\left(A\right)$ is the correct answer.