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NEETPhysicsAlternating Current

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In a series LCR circuit connected to an AC source, decreasing the capacitance will always result in a decrease in the rms current. Reason (R): Decreasing the capacitance increases the capacitive reactance, which decreases the net impedance if the circuit is initially inductive ( X_L > X_C ). In the

Options

  1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
  2. BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
  3. CAssertion (A) is true but Reason (R) is false.
  4. DAssertion (A) is false but Reason (R) is true.

Correct answer

D. Assertion (A) is false but Reason (R) is true.

Step-by-step solution

The capacitive reactance is given by X_C = 1 C . When the capacitance C is decreased, the capacitive reactance X_C increases. The net impedance of a series LCR circuit is Z = R^2 + (X_L - X_C)^2 . If the circuit is initially inductive ( X_L > X_C ), an increase in X_C will reduce the magnitude of the difference (X_L - X_C) . This causes the net impedance Z to decrease. Since the rms current is I_ rms = V_ rms Z , a decrease in the impedance Z leads to an increase in the rms current. Therefore, decreasing the capaci

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