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Current Electricity
Electrical Energy and Efficiency
1 question from 1 paper, each with its answer.
- question
- 1
- paper
- 1
- of Current Electricity
- 0.77%
Concepts tested
- Watt-hour efficiency
All Questions
2004 AIPMT 1 question
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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 hours. The mean terminal voltage during discharges is 14 V. The "Watt hour" efficiency of the battery is :-Watt-hour efficiency $= \dfrac{\text{energy given out on discharge}}{\text{energy supplied while charging}} \times 100$
Energy in (charging) $= V I t = 15 \times 10 \times 8 = 1200$ Wh
Energy out (discharging) $= 14 \times 5 \times 15 = 1050$ Wh
Efficiency $= \dfrac{1050}{1200} \times 100 = 87.5$ percent
So the watt-hour efficiency of the battery is 87.5%.