A battery is charged at potential of 15 V for 8 h by means of a current of 10A. While discharging it supplies a current 5A for 15h at a potential difference of 14 V. Calculate the watt-hour efficiency of the battery.

Explanation

Watt-hour efficiency or energy efficiency
`=(en ergy obta i n eddur i ng dischargi n g)/(en er gy su pplied dur i ng charg i ng)`
`=(14times5times15)/(15times10times8)=7/8=0.875=87.5%`