Practice portal › Alternating Current › AC Through R, L and C

An inductive reactance of an inductor is ____.

Asked in GSEB Board March 2022 · Reactance and frequency

Answer: (4) ω L

Step-by-step solution

Idea: an inductor develops a back emf L(dI)/(dt), so it opposes the current more strongly the faster the current changes.

For I = I₀ sin ω t: V_L = L(dI)/(dt) = ω LI₀ cos ω t, so the voltage amplitude is V₀ = (ω L)I₀.

The ratio (V₀)/(I₀) is the reactance: X_L = ω L = 2π fL, measured in ohm.

Why the other options are wrong

More AC Through R, L and C questionsAll AC Through R, L and C questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer