Question

An electric bulb of rating $\text{50 W}$ is used for $\text{8 hr}$ in one day. Find the number of units of energy used by the electric bulb in a day.

• A. 200 unit
• B. 0.4 unit
• C. 0.6 unit
• D. 400 unit

Answer 1

The correct option is B

0.4 unit

$\text{50 W = 0.05 kW}$

$\text{Time}=8\text{hrs}$
$\text{Energy consumed}=\text{Power}\times \text{time}$

$=0.05kW\times 8hrs=0.4kWh=0.4\text{unit}$