A 220 volt and 1000 watt bulb is connected across a 110 volt mains supply.

A 220 volt and 1000 watt bulb is connected across a 110 volt mains supply. The power consumed will be

(a) 1000 W
(b) 750 W
(c) 500 W
(d) 250 W

250 W

P = V² / R. A bulb has a fixed resistance.

⇒ P₁ / P₂ = V₁² / V₂²

⇒ 10000 / P₂ = (220/110)² = 4

⇒ 4P₂ = 1000 ⇒ P₂ = 250 W

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