A battery is charged at a potential of `15 V` for `8` hours when the current flowing is `10 A`. The battery on discharge supplies a current of `5 A` for `15` hours. The terminal voltage during discharge is `14 V`. The 'Watt-hour" efficiency of the battery is.

Options

A. `80%`
B. `90%`
C. `87.5%`
D. `82.5%`

Answer

C

Explanation

% Watt hour efficiency =`E_"out"/E_"in"xx100 ="(14)(5)(15)"/"(15)(10)(8)"xx100`=87.5 %