Question 308: AC fundamentals

Question

A coil has inductance H . The ratio of its reactance when it is connected first to an a.c. source and then to d.c. source is

Accepted Answer

The reactance of a coil, known as inductive reactance, in an AC circuit is given by the formula:
$$ X_L = 2\pi f L $$
where $ f $ is the frequency of the AC source and $ L $ is the inductance of the coil.
In a DC circuit, the frequency $ f $ is 0, so the inductive reactance of the coil is:
$$ X_{L, 	ext{DC}} = 2\pi (0) L = 0 $$
In contrast, the inductive reactance in an AC circuit with a non-zero frequency $ f $ is:
$$ X_{L, 	ext{AC}} = 2\pi f L $$
The ratio of inductive reactance for AC to DC is then:
$$ \frac{X_{L, 	ext{AC}}}{X_{L, 	ext{DC}}} = \frac{2\pi f L}{0} = \infty $$
Thus, the ratio of the coil's reactance when connected first to an AC source and then to a DC source is:
Option A: $\infty$

Answer

$\infty$

Answer

zero

Answer

one

Answer

two

AC fundamentals

A coil has inductance H . The ratio of its reactance when it is connected first to an a.c. source and then to d.c. source is

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