Question

A 5.5-kW resistance heater in a water heater runs for 3 hours to raise the water temperature to the desired level. Determine the amount of electric energy used in both kWh and kJ.

Answer 1

16.5 kwh and 59400 kJ.

Step-by-step explanation:

kWh is a measure of energy that is equivalent to the power in kw times the number of hours the device worked.

In this case, it would be equal to:

`E_(kwh)=5.5kw*3h=16.5kwh`

1 kw also means 1kj of energy spent per second. With this, we calculate the amount of energy in kJ spent by the resistance:

`E_(kJ)=5.5(kJ)/(s)*3h*(3600s)/(1h) = 59400 kJ`