Question

Two circular coil can be arranged in any of the three situations shown in figure. Their mutual inductance will be-

• A. Maximum in situation $\left(\text{A}\right)$
• B. Maximum in situation $\left(\text{B}\right)$
• C. Maximum in situation $\left(\text{C}\right)$
• D. The same in all situations

Answer 1

The correct option is A Maximum in situation $\left(\text{A}\right)$

From, the principle of mutual inductance,

${\varphi }_2=M{i}_1\Rightarrow M=\frac{{\varphi }_2}{i_1}$

Where, ${\varphi }_2=\text{Flux through the second coil}{i}_1=\text{Current in the first coil}M=\text{Co-efficient of mutual inductance}$

Mutual inductance between two coils depends on their degree of flux linkage, i.e. the fraction of flux linked with one coil which is when some current passes through the other coil.

As we know, in circular loop's field will be directed along the axis of the loop. Hence, due to this field, flux linkage in another will be maximum, when both are placed co-axially.

$\therefore$ In situation $\left(\text{A}\right)$ the plane of the given two coils are parallel to each other. Hence, in this situation, maximum flux passes through them.

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(A\right)$ is the correct answer.