Question

An electric heater is rated 1500 W. How much energy does it use in 10 hours?

Answer 1

We know that, Energy = Power × time 

Here, Power = 1500 W

Time = 10 hours = 10 × 60 × 60 seconds = 36000 seconds 

Therefore,

The energy used by heater        = Power × time 

                                                   = 1500 × 36000 J 

                                                   = 54000000 J 

                                                   = 5.4 × 10⁷ J