Question

An electric heater of power 3 kW is used for 10 hours. How much energy does it consume? Express your answer in (i) kWh, (ii) joule.

Answer 1

Given,

Power = 3 kW

Time = 10 hours

(i) Electrical energy = Electrical power $\times$ Time = 3 kW $\times$ 10 hours = 30 kWh

(ii) Since 1 KWh = $3.6\times {10}^{6}J$

Electrical energy =$30\times 3.6\times {10}^6=108\times {10}^{6}J$