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

A 220 volt, 1000 watt bulb is connected across a 110 volt mains supply. The power consumed will be
  1. $750 \mathrm{watt}$
  2. $500 \mathrm{watt}$
  3. $250 \mathrm{watt}$
  4. $1000 \mathrm{watt}$

Solution

$\mathrm{p}=\frac{\mathrm{V}^2}{\mathrm{R}}$ or $\mathrm{R}=\frac{(220)^2}{1000}$ Power consumed $=\frac{\mathrm{V}^2}{\mathrm{R}}=\frac{110 \times 110}{220 \times 220} \times 1000=250$ watt

Asked in: JEE Main 2003

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