Question

An electric refrigerator rated 400W operates 8 hours per day. What is the cost of the energy to operate it for one month at a rate of Rs 5.00 per unit.

Answer 1

Here,Power P=400 W=400/1000 kW=0.40 kW

Time t=8 x 30=240 hours

Now electrical energy is given by,

E=P x t

=0.40 x 240=96 kWh

Thus the electric energy consumed by the refrigerator in a month of 30 days is 96 kWh.

Cost of 96 kWh of electricity=96 x 5= Rs. 480