Question

Which of the following conditions is necessary, to get induced emf across the secondary coil, in case of mutual inductance?

$\left(A\right)$. The primary and secondary coils must be arranged such that they do not share any magnetic flux.

$\left(B\right)$. The primary and secondary coils must be arranged such that they share magnetic flux.

$\left(C\right)$. The current in the primary coil must remain constant.

$\left(D\right)$. The current in the primary coil must vary with time.

• A. $\left(A\right)$ and $\left(C\right)$
• B. $\left(A\right)$ and $\left(D\right)$
• C. $\left(B\right)$ and $\left(D\right)$
• D. $\left(B\right)$ and $\left(C\right)$

Answer 1

The correct option is C $\left(B\right)$ and $\left(D\right)$

In order to obtain induced emf in the secondary coil, the following two conditions must be satisfied.

$\left(i\right)$ The primary and secondary coils must be arranged such that they share magnetic flux.

$\left(ii\right)$ The current in the primary coil must vary with time.

Therefore, statements $\left(B\right)$ and $\left(D\right)$ are correct.

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