NEET · Physics · STD 12 -7. Alternating current

A small signal voltage \(V(t) = V_0\,\, sin \omega \,t\) is applied across an ideal capacitor \(C\)

A Over a full cycle the capacitor \(C\) does not consume any energy from the voltage source.
B Current \(I(t)\) is in phase with voltage \(V(t).\)
C Current \(I(t)\) leads voltage \(V(t)\) by\(180^o.\)
D Current \(I(t)\) lags voltage \(V(t)\) by \(90^o.\)

Verified Solution

Answer & Solution

Correct Answer

(A) Over a full cycle the capacitor \(C\) does not consume any energy from the voltage source.

Step-by-step Solution

Detailed explanation

When an ideal capacitor is connected with an ac voltage source, current leads voltage by \(90°\) . Since, energy stored in capacitor during charging is spent in maintaining charge on the capacitor during discharging . Hence over a full cycle the capacitor does not consume any energy from the voltage source

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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