Question

An electric bulb consumes $7.2\text{kJ}$ of electrical energy in $2$ minutes. What is the power of the bulb?

• A. $40\text{W}$
• B. $60\text{W}$
• C. $50\text{W}$
• D. $70\text{W}$

Answer 1

The correct option is B $60\text{W}$

Given:
Energy $\text{E}=7.2\text{kJ}=7.2\times {10}^3\text{J}$
Time $\text{t}=2\text{min}=2\times 60=120\text{s}$
We know that power, $\text{P}=\frac{\text{Energy}}{\text{t}}=\frac{7.2\times {10}^3}{120}=60\text{W}$

$\therefore$ The power of the electric bulb is $60\text{W}$.