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On decreasing the angular frequency of the A.C. source used in an L-C-R series circuit, the capacitive reactance ______ and the inductive reactance ______.

Asked in RS Academy GUJCET booklet · Reactance and frequency

Answer: (1) increases, decreases

Step-by-step solution

Idea: the two reactances depend on frequency in opposite ways.

X_C = 1/(ω C) is inversely proportional to ω, so it increases when ω decreases. (A capacitor blocks slow changes; for d.c., ω = 0, it blocks completely.)

X_L = ω L is proportional to ω, so it decreases when ω decreases. (An inductor passes slow changes easily.)

So the capacitive reactance increases and the inductive reactance decreases.

Why the other options are wrong

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