Question

An electrical appliance of 100 W is used for 3 h per day. Calculate the units of energy consumed per day and for a month.

Answer 1

Power of electrical appliance 

= 100 W = 0.1 kW

Time used = 3 h

Energy = power x time taken

= 0.1 kW x 3 h

= 0.3 kWh

= 0.3 units 

(∵ 1 kWh = 1 unit)

The units of energy consumed per day = 0.3 units and for a month

= 0.3 x 30

= 9 units.