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Two 100-W bulbs are connected in series across 220 V. The total power consumed is:
A50 W
B100 W
C200 W
D400 W
Answer & Solution
Correct answer: A. 50 W
1. Each 100-W bulb at 220 V has R = V²/P = 220²/100 = 484 Ω.
2. In series, total R = 2 × 484 = 968 Ω; voltage 220 V gives I = 220/968 ≈ 0.227 A.
3. Total power = V·I = 220 × 0.227 ≈ 50 W.
4. In series, two identical bulbs share half their normal voltage each → ¼ rated power each → 50 W total.
_Source: NCERT Class 12 Physics Ch 3 §3.10 (combinations and power)_
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