Question

If an electric bulb of 100 watt is lighted for 2 hours .how much electric energy would be confused?

Answer 1

1 watt = 1 joule/sec.

Hence, 100 watts = 100 joules/sec.

For 2 hr
Energy used = 100 x 7200 =720000 J.

Answer 2

Q. If an electric bulb of 100 watt is lighted for 2 hours, how much electricity is consumed?

$\huge{\underline{\tt{\blue{Sloution-}}}}$

$\small\implies{\sf\green{Power-}}$ Power of a machine is defined as work done by the machine per second.

$\longrightarrow \sf{Power = \dfrac{energy}{Time}}$

$\longrightarrow \sf{= 100\times2Wh=200Wh}$

$\longrightarrow \sf{ = \dfrac{200}{1000}}kWh$

$\longrightarrow \sf{=0.2kWh}$