JEE MAIN - Physics (2022 - 28th June Evening Shift - No. 5)
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)
25
50
100
18
Explanation
Total gravitational PE of water per second $$ = {{mgh} \over T}$$
$$ = {{9 \times {{10}^4} \times 10 \times 40} \over {3600}} = {10^4}$$ 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
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