Revision Notes

4.2.6 Electromotive Force

What is Electromotive Force?

  • The Electromotive Force (EMF) is the name given to the Potential Difference (Voltage) of the power source in a circuit
  • The Electromotive Force (EMF) is measured in Volts (V)


Electromotive force, IGCSE & GCSE Physics revision notesThe EMF is the voltage supplied by a power supply: 12 V in the above case



Exam Question: Electromotive Force

Extended Only

EMF & Energy

  • The EMF of a power supply (measured in volts, V) is the amount of energy (measured in joules, J) supplied to each coulomb of charge passing through that power supply

Exam Tip

Think of the EMF as being the energy per coulomb.

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