Question

An electric bulb is rated 220 volt and 100 watt. Power consumed by it when operated on 110 volt is

• A. 50 watt
• B. 75 watt
• C. 90 watt
• D. 25 watt

Answer 1

Answer: (D)

25 watt

Answer 2

Resistance of the bulb = $\frac{V^{2}}{P_{Ratate}} = \frac{220 \times 220}{100} = 484\Omega$When connected with 110 V, the power consumed $P_{Consumed} = \frac{V^{2}}{R} = \frac{110 \times 110}{484} = 25W$