Question

A $220\, volts$ and $100\, watt$ bulb is connected to a $110$ volt source. What is the power consumed by the bulb?

• A. 25W
• B. 20W
• C. 30W
• D. 50W

Answer 1

Answer: (A)

25W

Answer 2

Using , P = $\frac{V^2}{R}$ , we get R =$\frac{V^2}{P} = \frac{220 \times 220}{100}$ $\therefore$ Power consumed = $\frac{V_1^2 }{R} = \frac{110 \times 110}{484}$ = 25 watt