InterviewSolution
Saved Bookmarks
| 1. |
Water falling from a `50m` high fall is to be used for generating electric energy. If `8xx10^5kg` in water falls per hour and half the gravitational potential energy can be converted into electric energy, how many `100W` lamps can be lit? |
|
Answer» `h=50m`, `m=1.8xx10^5kg`, `P=100W` `PE=mgh=1.8xx10^5xx10xx50=900xx10^5Jh^-1` Because half the potential energy is converted into electricity Electrical energy `=1/2PE=450xx10^5Jh^-1` So, power in watt `(Js^-1)=(450xx10^5)//(3600)` The number of `100W` lamps that can be lit `=(450xx10^5)/(3600xx100)=125` |
|