Question

11. An electric refrigerator is connected to a 220v supply. Assume the internal resistance of the refrigerator is 110 sΩ. The refrigerator operates 8 hour/day.

Find out:
a) The power of the refrigerator in watt (W)
b) What is the cost of the energy to operate it for 30 days at Rs 2.00 per kW h?

Answer 1

Answer:

a) 440 W (watt)

b) Rs. 211.1

Explanation:

a) V=220v

   R=110ohm

Power = V^2/R  = (220)^2/110 = 440 W(watt)

b)For 8 hrs

Electrical Energy(Kwh ) = Power*Time = V^2/R*t = 440/1000*8 = 3.52Kwh

Cost for 30days = Electical energy * 30 days * Cost = 3.52*30*8 =Rs.211.2