GCSE Physics

Potential Difference or Electromotive Force

The energy available to drive a flow of current* is called potential difference or electromotive force (EMF). It is provided by an energy source such as a cell* or mains supply and is measured in volts by a voltmeter:

Symbol for a voltmeter

One volt is the energy required to drive a current of one amp* through a circuit* with a resistance of one ohm*.

Voltage is represented by the symbol, V.

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