Two conducting circular loops of radii a and b are placed in the same plane with their centre coinciding. If a >> b, the mutual inductance M between then will be directly proportional to:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $\frac{b^2}{a}$
The mutual inductance (M) is -
$M=\frac{μ_0}{2\pi}×\frac{ab}{\sqrt{a^2+b^2}}$
$⇒M∝\frac{b}{\sqrt{a}}∝\frac{b^2}{a}$