An electric bulb is rated as 220 V and 80 W. When it is operated on 110 V, the power rating would be :
- A. 80 W
- B. 60 W
- C. 40 W
- D. 20 W ✓
Correct Answer: D. 20 W
Explanation
Power P = V^2 / R. When the voltage is halved (from 220 V to 110 V), the power consumed becomes one-fourth of the original rating (80 W / 4 = 20 W).
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