What is power ? How do you differentiate killowatt from kilowatt hour ? The Jog Falls in Karnataka state are nearly 20 m high. 2000 tonnes of water falls from it in a minute. Calculate the equivalent power if all this energy can be utilized ? `(g = 10 m//s^2)`

Explanation

The rate of doing work is called power . Further , a kilowatt (kW) is the unit of power where 1 kW = 1000 W
= 1000 J//s and a kilowatt hour (kWh) is the unit of energy, where
`1 kWh = 1000 W xx 1h = (1000 J//s) (3600 s) = 36 xx 10^5 J`
Mass of water falling per minute, `m = 2000 tonnes = 2000 xx 10^3 kg = 2 xx 10^6 kg`
Height through which water falls, h = 20 m
PE of the water, `W = mgh = (2xx10^6) (10) (20) = 4xx 10^8 J`
Power of the falling water `=(W)/(t) = (4xx10^8 J)/(60 s) = (2//3) xx 10^7 W (as t =1 min. = 60s)`