Answer:
The electrical energy is 13.5 kWh or 48600 kJ
Step-by-step explanation:
Given that,
The power of the resistance heater, P = 4.5 kW
The water heater runs for 3 hours to raise the water temperature to the desired level.
We need to find the amount of electric energy used in both kWh and kJ.
Energy = Power × time
E = 4.5 kW × 3 h
= 13.5 kWh
Since,
1 kWh = 3600 kJ
13.5 kWh = 48600 kJ
Hence, the required electrical energy is 13.5 kWh or 48600 kJ