Ok, so 90000000 J is converted to 45000000 J of electric energy. As 1 watt = 1 joule per second, 45000000 J/ 3600 s gives 12500 W. So, is the answer 125 bulbs (12500 W/ 100 W) ? If it is, Thanks a lot.
Using the mgh formula, I multiplied 180000 kg, 50 m and 10 m/s^2. It gave 90000000 kgm^2/s^2. I made a mistake, kgm^2/s^2 equals just Joules and there is no seconds.
Could anyone help me with this sum - To generate electricity, 180000 kg water is dropped from a height of 50 m (let g = 10 m/s^2). If half the gravitational potential energy is converted to electric energy, how many 100 W bulbs can be lit ?
Formula - Ep = mgh
I calculated the potential energy...