Question

11. How much energy does a 100-W light bulb use in 8.0 hours? (Note: 1kWh = 3.6x106 Jor 1kWx 1hour) O 800 kWh O 13 kWh O 0.008 kWh O 0.8 kWh

Answer 1

We know that Power (in Watt), $P = \frac{E}{t}$

where E is energy (in Joule) and t is time (in seconds).

In the question we have 100 W light bulb means the bulb use 100 J energy per second.

Then, in 8 hours means in 28800 seconds the bulb use the energy =

100 x 28800 = 2880000J = 0.8kWh