Editing Efficiency (section)

=== In physics ===
* Useful work per quantity of energy, mechanical advantage over ideal mechanical advantage, often denoted by the Greek lowercase letter η ([[Eta]]):
** [[Electrical efficiency]]
** [[Energy conversion efficiency]]
** [[Mechanical efficiency]]
** [[Thermal efficiency]], ratio of work done to thermal energy consumed
* [[Efficient energy use]], the objective of maximising efficiency
** In thermodynamics:
*** [[Energy conversion efficiency]], measure of second law thermodynamic loss
** [[Radiation efficiency]], ratio of radiated power to power absorbed at the terminals of an antenna
** [[Volumetric efficiency]], in internal combustion engine design for the RAF
* [[Lift-to-drag ratio]]
* [[Faraday efficiency]], electrolysis
* [[Quantum efficiency]], a measure of sensitivity of a photosensitive device
* [[Grating efficiency]], a generalization of the reflectance of a mirror, extended to a diffraction grating