Question 245: Electromagnetic Induction

Question

When the number of turns in a coil is doubled without any change in the length of the coil, its self-inductance

Accepted Answer

The self-inductance of a coil is given by the formula:
$$ L = \mu \frac{N^2 A}{l} $$
where:
$ L $ is the self-inductance,
$ \mu $ is the permeability of the core material,
$ N $ is the number of turns in the coil,
$ A $ is the cross-sectional area of the coil, and
$ l $ is the length of the coil.
When the number of turns $ N $ is doubled, the expression for self-inductance becomes:
$$ L' = \mu \frac{(2N)^2 A}{l} = \mu \frac{4N^2 A}{l} = 4 \left( \mu \frac{N^2 A}{l} \right) = 4L $$
Thus, the self-inductance becomes 4 times the original value. Therefore, the correct answer is:
Option A: becomes 4 times.

Answer

becomes 4 times.

Answer

becomes 2 times.

Answer

gets halved.

Answer

remains unchanged.

Electromagnetic Induction

When the number of turns in a coil is doubled without any change in the length of the coil, its self-inductance

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