P1 - Efficiency | Mind Map

P1 - Efficiency

most energy transfers involve some waste energy
1. useful devices are only useful because they can transfer energy from one store to another
2. some of the input energy is usually wasted by being transferred to a useless energy store - usually the thermal energy store
3. the less energy that is 'wasted' in this energy store, the more efficient the device is said to be
4. you can improve the efficiency of energy transfers by insulating objects, lubricating them or making them more streamlined
EQUATION - Efficiency = useful output energy transfer/ total input energy transfer
you might not know the energy inputs and outputs of a device but you can still calculate efficiency as long as you know the power inputs and outputs
1. EQUATION - Efficiency = useful power input / total power input
useful energy input isn't usually equal to total energy output
1. for any given example you can talk about the types of energy being input and output
  1. but remember: NO device is 100% efficient and the wasted energy is usually transferred to useless thermal energy stores.
2. Electric heaters are the exception to this. They're usually 100% efficient because all the energy in the electrostatic energy store is transferred to 'useful' thermal energy store
3. Ultimately, all energy ends up transferred to thermal energy stores.
  1. E.g if you use an electric drill, its energy transfers to lots of different energy stores, but quickly ends up all in the thermal energy stores.

P1 - Efficiency

	Created by Flo Sumpter almost 4 years ago