Efficiency
A device takes 400 J input and delivers 280 J useful output. Efficiency is:
Select the correct option:
Solution
70%
Efficiency (η) is the ratio of useful energy output to total energy input: η=Total InputUseful Output×100% η=400 J280 J×100=0.70×100=70%.
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About This Question
- Subject
- physics
- Chapter
- work, energy and power
- Topic
- efficiency
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
70%
Efficiency (η) is the ratio of useful energy output to total energy input: η=Total InputUseful Output×100% η=400 J280 J×100=0.70×100=70%.
This medium difficulty physics question is from the chapter work, energy and power, covering the topic of efficiency. It appeared in the 2025 exam.
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