When three identical bulbs of 60 W-200 V rating are connected in series to a 200 V

When three identical bulbs of 60 W-200 V rating are connected in series to a 200 V supply, the power drawn by them will be

(a) 60 W
(b) 180 W
(c) 10 W
(d) 20 W

20 W

In series, Resultant resistance = R₁ + R₂ + R₃ = R + R + R = 3R

Power = V² / R ⇒ 60 = V² / R ⇒ V² = 60 R

Power of combination = P

P = V² / Resistance of combination = 60 / 3 R = 20 W

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