What is power? How do you differentiate kilowatt 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? $(g = 10 \, m \, s^{-2})$

(N/A) Power is defined as the rate of doing work or the rate of energy transfer.
Kilowatt $(kW)$ is a unit of power, representing $1000 \, J/s$. Kilowatt hour $(kWh)$ is a unit of energy, representing the energy consumed by a device of $1 \, kW$ power in $1 \, hour$.
Given: Height $(h) = 20 \, m$, Mass $(m) = 2000 \, \text{tonnes} = 2000 \times 1000 \, kg = 2 \times 10^6 \, kg$, Time $(t) = 1 \, \text{minute} = 60 \, s$, Acceleration due to gravity $(g) = 10 \, m \, s^{-2}$.
Potential Energy $(PE) = mgh = 2 \times 10^6 \times 10 \times 20 = 4 \times 10^8 \, J$.
Power = $\frac{\text{Energy}}{\text{Time}} = \frac{4 \times 10^8 \, J}{60 \, s} = \frac{40}{6} \times 10^7 \, W = 6.67 \times 10^6 \, W$ or $6.67 \, MW$.