Find the energy in kW h consumed in 10 hours by four devices of power 500 W each.

We know that, \( P \ = \ \frac{W}{T} \)

Where,

Power rating of the device(P)
= 500 W
= 0.50 KW

T= 10 hrs,

Work done
= energy consumed × Time

= 0.50 × 10 = 5 kWh

Hence, the energy consumed by four equal rating devices in

10 h = 4 × 5 kWh = 20 kWh = 20 Units.