JEE Main 2022 · 28 Jun · Shift 2, Physics question 35

Water falls from a 40 m high dam at the rate of $9\times10^4$ kg per hour. Fifty percentage of gravitational potential energy can be converted into electrical energy. Using this hydro electric energy number of 100 W lamps, that can be lit, is :

(Take $g=10$ ms$^{-2}$)