Question 210: Electromagnetic Induction

Question

Two identical coils of inductance $L$ joined in series are placed very close to each other such that the winding direction of one coil is exactly opposite to that of the other. The net inductance is

Accepted Answer

When two inductors are joined in series then, $\mathrm{L}_{	ext {total }}=\mathrm{L}_1+\mathrm{L}_2+\ldots+\mathrm{L}_{\mathrm{n}}$
Since the two inductors are placed very close to each other, they are mutually coupled, meaning there is mutual inductance between them. As the winding direction of one coil is exactly opposite to that of the other, the magnetic fields produced by the currents oppose each other. This causes the polarity of the mutual inductance to be opposite to that of the self-inductance. As as result, net inductance will be given by
Net Inductance $=\mathrm{L}+\mathrm{L}-2 \mathrm{M}$
Net Inductance $=2 \mathrm{~L}-2 \mathrm{~L}=0 \quad \ldots .(\mathrm{M}=\mathrm{L}$ as they are identical coils placed very close to each other)

Answer

$\frac{\mathrm{L}}{2}$

Answer

2 L

Answer

zero

Answer

L

Electromagnetic Induction

Two identical coils of inductance L joined in series are placed very close to each other such that the winding direction of one coil is exactly opposite to that of the other. The net inductance is

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