A radio set of 60 watts runs for 50 hours. How many 'units' (kWh) of electrical energy are consumed ?

Explanation

We want to calculated the electrical energy in kilowatt-hours, so first we should convert the power of 60 watts into kilowatts by dividing it by 1000. That is :
Power, P =60 watts
`= (60)/(1000)` kilowatts
= 0.06 kW
And, Time, t = 50 h
Now, putting P = 0.06 kW and t = 50 h in formula:
`"Power" = ("Energy comsumed")/("Time taken")`
We get : `0.06 kW = ("Energy consumed")/(50 h)`
So, Energy consumed `= 0.06 kW xx 50 h`
= 3 kWh
Thus, the electrical energy consumed is 3 kWh or 3 units.