Calculate the electricity bill for month of May @ Rs. 4/unit if following devices run together for 7hrs a day: 1) 5 bulbs of 50W each; 2) 4 fans of 120 W each & 3) An electric motor of power 2.5kW.
Answers
Answer:
1)
Power = 50×5=250W = 0.25kW
Time = 7h
Energy = kWh = 0.25kW x 7h = 1.75kWh
Cost @₹4/unit = 1.75×₹4 = ₹7
2)
Power = 120×4 = 480W = 0.48kW
Time = 7h
Energy = kWh = 0.48kW × 7h = 3.36kWh
Cost =3.36 x 4 = ₹13.44
3)
Power = 2.5kW
Time = 7h
Energy = 2.5kW × 7h = 17.5kWh
Cost = 17.5 × 4 = ₹70
one unit = 1 kw hr
unit cost = Rs 4/day
1) power consumed by 5 bulbs of 50 w for 7 hr =>
5×50×7 => 250 × 7 => 1750 watt => 1750/1000 = 1.75 kw
=> 1.75 units/day => 1.75 × 31 => 54.25 units ____1
2) power consumed by 4 fans of 120 w for 7 hr =>
=> 4 × 120 × 7 => 3360 watt => 3360/1000 => 3.36 kw
=> 3.36 units/day => 3.36 × 31 => 104.16 units ___2
3) power consumed by motor of 2.5 kw for 7 hours
=> 2.5 × 7 => 17.5 kw => 17.5 × 31 => 542.5 units__3
total units for the month of May = 1 + 2 +3
=> 54.25 + 104.16 + 542.5 => 700.91 units/month
total bill = 700.91 × 4 => Rs 2803.64
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