Question

A battery is charged at a potential of 15V for 8 hours when the current flowing is 10A. The battery on discharge supplies a current of 5A for 15 hour. The mean terminal voltage during discharge is 14V. The “Watt-hour” efficiency of the battery is(a) 87.5%(b) 82.5%(c) 80%(d) 90%

Answer 1

HIII.....

I THINK OPTION B IS CORRECT

Answer 2

Answer:

a) 87.5%

Explanation:

Watt is defined as the hour efficiency of a battery, that is the ratio of the amount of energy available during the discharge of a battery to the amount of energy during charging.

Electrical energy = Voltage x Power x time

Energy available during discharge = VIt = 14 x 5 x 15 = 1050 kWh

Energy put in during charging = VIt = 15 x 10 x 8 = 1200 kWh

Watt - hour efficiency = Energy released during discharge/ Energy gained during charging × 100

Watt - hour efficiency  =   (1050/1200)x100

= 87.5%

Thus, The “Watt-hour” efficiency of the battery is 87.5%.