Question

Find mass of water falling from a height of 50m in 5minutes to generate 2MW of Electrical power if 40 % energy of falling water is wasted.​

Answer 1

Answer:

h = 50m, m =1.8×10

5

hr

kg

, P = 100 watt,

P.E. = mgh = 1.8×10

5

×9.8×50 = 882×10

5

hr

J

Because, half the potential energy is converted into electricity,

Electrical energy

2

1

×P.E. =441×10

5

hr

J

So, power in watt is given by =

3600

441×10

5

∴ number of 100 W lamps, that can be lit

360000

441×10

5

= 122.5 = 122