Question

In a house, 3 bulbs of 100 watt each, are lit for 5 hours daily and an electric heater of 1.0 kW is used for half an hour daily. Calculate the total energy consumed in a month of 30 days and its cost at the rate of ₹ 3.60 per kWh.

Answer 1

Given: 3 bulbs of 100 W each

Total power = 3 × 100 = 300 W = 0.3 kW

Time = 5 hours/day

Heater power = 1.0 kW

Time = 0.5 hours/day

Days = 30

Cost = ₹ 3.60 per kWh

Energy consumed by bulb per day (E₁) = 0.3 × 5

= 1.5 kWh

Energy consumed by heater per day (E₂) = 1.0 × 0.5

= 0.5 kWh

Total energy consumed per day (E) = E₁ + E₂

= 1.5 + 0.5

= 2.0 kWh

Energy consumed in 30 days (E_total) = 2.0 × 30

= 60 kWh

Cost = 60 × 3.60

= 216

∴ The total energy consumed in a month of 30 days is 60 kWh, and its cost is ₹ 216.