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

Explanation

Here, total power of the four devices, `P = 4xx500 W = 2000 W = 2kW`
time for which the devices are operated `t = 10h`
Energy consumed by the four devices, i.e.,
`W = P xx t = (2kW) (10h) = 20 kWh = 20` units