Edexcel A-level Physics Energy transfer
This page covers the following topics:
Energy can never be created or destroyed, it is only ever converted from one store to another usefully or dissipated into the surroundings.
It is important that you can identify key energy transfers in common electrical appliances including both useful and wasted energy. For example, in a kettle, food processor or lamp.
Energy transfers as useful energy, or it is stored, or it is dissipated into the surroundings. Questions can include common transfers you are familiar with, or new machinery that you will have to read the information given carefully to write your answers.
Sankey diagrams are used to visually represent the efficiency of an energy transfer, for example the efficiency of an electronic device.
In a closed system energy and matter cannot leave the system, therefore the energy input will equal the energy output.
Efficiency is the ratio of useful work done by a machine compared to the total energy supplied. It is calculated using the equation in the shown image.
End of page