Question

In series LCR circuit $R=18\Omega$ and $Z=30\Omega$. An rms voltage 210 V is applied. The true power consumed is nearly

• A. 210 W
• B. 400 W
• C. 800 W
• D. 900 W

Hint:

Only resistance consumes "true" power in an AC circuit; L and C consume zero average power.

Answer 1

The Correct Option is D

Step 1: Formula
True Power $P = I_{rms}^2 R$.

Step 2: Analysis
$I_{rms} = V_{rms}/Z = 210/30 = 7$ A.

Step 3: Calculation
$P = (7)^2 \times 18 = 49 \times 18 = 882$ W.

Step 4: Conclusion
Rounding to the nearest option, the power is nearly 900 W. Final Answer: (D)