Question

Question 20
Find the energy in kWh consumed in 10 hours by four devices of power 500 W each.

Answer 1

Energy consumed by an electric device can be obtained with the help of the expression for power,
$P=\frac{W}{T}$
where,power rating of the device, $P=500W=0.50kW$
time for which the device runs, $T=10h$
Work done = Energy consumed by the device
Therefore, energy consumed = Power $\times$ Time $=0.50\times 10=5kWh$
Hence, the energy consumed by four equal rating devices in $10h$ will be $4\times 5kWh=20kWh$.