2.4 Energy and Efficiency

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  • Created by: Twins 1&2
  • Created on: 16-06-13 10:56

2.4 Energy and Efficiency

Energy is measured in Joules ( J ). This unit is used for all forms of energy.

The energy supplied to a machine is called the input energy.

Input energy = useful energy output + wasted energy

Efficiency = useful energy output  /  total energy input

Efficiency can be left as a fraction or multiplied by 100 to give a percentage.

The energy transfer through an appliance can be shown in a sankey diagram.

As efficiency is a ratio it does not need a unit.

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2.4 Energy and Efficiency


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