Physics GCSE
Efficiency
What Efficiency means in Physics GCSE, as defined for AQA, OCR.
Definitions of Efficiency
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Reference: AQA
Compares the useful energy or power transferred by a device with the total energy or power supplied to it, and is always between 0 and 1, or between 0% and 100%.
Compares the useful energy a device delivers with the total energy supplied to it, calculated as useful output energy transfer divided by input energy transfer.
The ratio of useful output energy transfer to total input energy transfer, given by efficiency = useful output energy transfer ÷ total input energy transfer.
By reducing unwanted transfers, a greater proportion of the input energy is transferred usefully, thereby increasing the overall efficiency of the system.
A comparison of useful output energy with total input energy, which increases when a greater proportion of the input energy is transferred usefully.
A measure of how much of the energy supplied to a device is transferred usefully rather than wasted, usually expressed as a decimal or percentage.
Topics that use Efficiency
- Efficiency (AQA GCSE)
- Energy transfers in a system (AQA GCSE)
- Power and efficiency (OCR GCSE)
Related terms
- Lubrication
- Rate of energy transfer
- thermal conductivity
- thermal insulation
- wasted energy
- Battery as chemical store versus mains a.c. supply
- comparing insulators
- conduction
Using Efficiency in the exam
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