At home, we pay our electric company for the energy we use in the units of kilowatt hours (kWh). One kilowatt hour is the amount of energy when one kilowatt of power is used for 1 hour.

Example: if a 100 W light bulb is left on for one hour, then the energy it uses is:

Energy=Power ×time

E=Pt

E = (0.1 kW) (1 h)

E = 0.1 kWh

If it costs 12 cents per kWh (about the average rate in Texas), then this will cost:

cost=kWh ×rate

cost = (0.1 kWh) (12 cents)

cost = 1.2 cents

Q 10. A typical computer consumes about 200 W of power. If it is left on for 24 hours, how much energy does it consume? How much will this cost (at the rate of 12 cents per kWh)?
 
 

Energy Power X time = =