Calculate the total cost of running the following electrical devices

• Electricity (C10)

Calculate the total cost of running the following electrical devices in the month of September, if the rate of 1 unit of electricity is Rs 6.00.

1. Electric heater of 1000 W for 5 hours daily.
2. Electric refrigerator of 400 W for 10 hours daily.

Answer

P₁ = 1000 W / 1000 = 1 kW

t₁ = 5 h

P₂ = 400 W / 1000 = 0.4 kW

t₂ = 10 h

No. of days, n = 30

E₁ = P₁ x t₁ x n

= 1 kW x 5 h x 30 = 150 kWh

E₂ = P₂ x t₂ x n

= 0.4 kW × 10 h × 30 = 120 kWh

Total energy = (150 + 120) kWh = 270 kWh

Total cost = 270 x 6 = Rs. 1620