Question

An electric bulb is rated 250 W, 230 V. The energy consumed in one hour is :

• A. $9\times {10}^5$ J
• B. $15\times {10}^5$ J
• C. $25\times {10}^5$ J
• D. $23\times {10}^5$ J

Answer 1

Answer: (A)

$9\times {10}^5$ J

Energy ($power\times time$) is measured in Joules and by including time (t) in the power formulae, the energy dissipated by a component or circuit can be calculated.

Energy dissipated Q= Pt.

In the question, the time taken is given as 1 hour = 60 minutes, that is $60\times 60=3600seconds$ and the power is 250 W.

Hence, the energy consumed by the bulb is $250W\times 3600s=9.00,000J.Thatis,9\times {10}^{5}Joules$.