Which uses more energy, a `250 W` TV set in `1 h` or a `1200 W` toaster in `10` minutes ?

Explanation

(i) For TV set: Power, `P = 250 W = (250)/(1000) kW = 0.25 kW`
Time, `t = 1h`
So, Electric energy, `E = P xx t`
(used by TV set) `E = 0.25 xx 1 kWh` ....(1)
`E = 0.25 kWh`
(ii) For toaster: Power, `P = 1200 W = (1200)/(1000) kW = 1.2 kW`
Time, `t = 10` min `= (10)/(60) h = 0.167 h`
So, Electric energy, `E = P xx t`
(used by toaster) `E = 1.2 xx 0.167 kWh`
`E = 0.20 kWh`
From the above calculations, is is clear that the TV set uses more energy (0.25 kWh) whereas toaster uses less energy (0.20 kWh).