Question

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

• A. 1000 watt
• B. 1500 watt
• C. 250 watt
• D. 750 watt

Answer 1

Answer: (C)

Resistance of bulb, $R=\frac{{\left(220\right)}^2}{1000}=\frac{484}{10}\Omega$
$\because$ New supplied voltage = 110 V
$\therefore$ Power consumed by it, $P=\frac{V^2}{R}$
$=\frac{(110{)}^2}{484}\times 10$
= 250 watt