The height of the dam, in an hydroelectric power station is 10 m. In order to generate 1 MW of electric power, the mass of water (in kg) that must fall per second on the blades of the turbine is 

Options

A. `10^6`
B. `10^5`
C. `10^3`
D. `10^4`

Answer

D

Explanation

Let `(dm)/(dt)` be the mass of water falling per second.
As `mgh =` work done `:. (dm)/(dt) gh = `power
Given `h = 10 m`
`:. (dm)/(dt) = (1 xx 10^6 W)/(10 ms^(-2) xx 10 m) = 10^4 kg s^(-1).`