Water falling from  a height of 50m is used to generate electricity. If 1.8 x 105 kg 
of water fall in a hour and half the gravitationbal potential energy is converted into electrical energy, how many light bulbs of 11W can be lit?

Asked by gpnkumar0 | 2nd Oct, 2017, 11:02: AM

Expert Answer:

begin mathsize 12px style space Given space that
straight h space equals space 50 space straight m comma space
straight m space equals space 1.8 space cross times space 10 to the power of 5 space kg divided by hr comma space
straight t space equals space 1 straight h space equals space 3600 space straight s
straight P space equals space 11 space straight W comma space space
Given space that space half space the space potential space energy space is space converted space into space electricity comma space so space we space have space space
Total space power space generated space equals space Energy over Time space equals space fraction numerator begin display style bevelled mgh over 2 end style over denominator straight t end fraction space equals space 12250 space straight W
Number space of space 11 straight W space lamps comma space that space can space be space lit space equals space 12250 over 11 equals 1113.63 space almost equal to space 1114 space bulbs space end style

Answered by Yashvanti Jain | 3rd Oct, 2017, 11:21: AM