Question

19. In a house, five 100 W electric bulbs are lit for
6 hours, and a 1500 W electric heater is used for
2 hours daily.
(a) Calculate the electrical energy consumed in
30 days.
(b) Calculate the cost if the rate is * 4 per unit.
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Answer 1

A) calculate the electricl energy comsumed in 30 days

Answer 2

a) Power of electric bulb = 100W = 0.1kWTime used, t = 6 hEnergy = power x time taken = 0.1 kW x 6 h = 0.6 kWh = 0.60.5unitsThus, the energy consumed by the bulb is 0.6units consumed by bulb

and1500W=1.5kW

therefore

energy consumed by heater is given by

1.5kW x 2h=3.0

total energy consumed

0.6+3.0=3.6

energy consumed in 30days

3.6 x 30 =108.0

b) cost will be

1unit cost for =4rs

cost of 1 day.....3.6 x 4 =10.4rs

cost of 30days 10.4x 30 = 312.0