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Matter In Our Surroundings
A 100 W electric bulb is lighted for 2 hours everyday and five 40 W tubes are lighted for 4 hours everyday. Calculate,
(i) the energy consumed for 60 days and
(ii) the cost of electricity consumed at the rate of Rs. 3 per kWh.
Given,
100 Watt bulb lighted for 2 hours.
Five 40 Watt tubes are lighted for 4 hours everyday.
(i) Energy consumed by a 100 W bulb each day is,
E= 100 W x 2 h
= 200 Wh
= 2001000
= 0.2 kWh
Energy consumed by five 40 W tubes each day,
E = 5 x 40 W x 4 h
= 800 Wh
= 8001000
= 0.8 kWh
Therefore,
Total energy consumed each day = 0.2 + 0.8 = 1.0 kWh
Total energy consumed in 60 days = 1.0 x 60 = 60 kWh
(ii) Cost fo 1 kWh of electricty = Rs. 3
So, cost of 60 kWh = 3 x 60 = Rs. 180.
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