Question 149: Gravitation

Question

Water falls from a 40 m high dam at the rate of 9 $$	imes$$ 104 kg per hour. Fifty percentage of gravitational potential energy can be converted into electrical energy. Using this hydroelectric energy number of 100 W lamps, that can be lit, is :
(Take g = 10 ms$$-$$2)

Accepted Answer

Total gravitational PE of water per second $$ = {{mgh} \over T}$$
$$ = {{9 	imes {{10}^4} 	imes 10 	imes 40} \over {3600}} = {10^4}$$ J/sec
50% of this energy can be converted into electrical energy so total electrical energy $$ = {{{{10}^4}} \over 2} = 5000$$ W
So total bulbs lit can be $$ = {{5000\,W} \over {100\,W}} = 50$$ bulbs

Answer

25

Answer

50

Answer

100

Answer

18

Gravitation

Water falls from a 40 m high dam at the rate of 9 $\times 104 kg per hour. Fifty percentage of gravitational potential energy can be converted into electrical energy. Using this hydroelectric energy number of 100 W lamps, that can be lit, is : (Take g = 10 ms-$2)

Choose the correct answer: