What is the Difference Between EMF and Potential Difference?

06/24/2025 • Giovanni Medeiros

The main difference between electromotive force (EMF) and potential difference lies in their definitions, units, and how they are affected by circuit resistance. Here's a side-by-side comparison of the two concepts:

Property EMF (Electromotive Force) Potential Difference (V)
Definition The amount of energy given to each coulomb of charge. It is the driving force in a circuit. The amount of energy utilized by one coulomb of charge. It is the result of the EMF within a circuit.
Unit Volts (V) Volts (V)
Internal Resistance Independent. Dependent.
Measurement Measured using an EMF meter. Measured using a voltmeter.

In summary, EMF is the driving force in a circuit, responsible for transferring energy across the circuit, while potential difference is the result of the EMF within a circuit and represents the amount of energy utilized by one coulomb of charge.

Comparative Table: EMF vs Potential Difference

Here is a table highlighting the differences between electromotive force (EMF) and potential difference:

Feature Electromotive Force (EMF) Potential Difference
Definition The amount of energy supplied to one coulomb of charge. The difference in potential energy per unit charge between two points in a circuit.
Variation Remains constant. Does not remain constant, depends on the circuit's internal resistance.
Relation Cause. Effect.
Unit Volt (V). Volt (V).
Measurement Measured using an EMF meter. Measured using a voltmeter.
Independence Independent of resistance. Dependent on resistance between two points.
Field Generated in electric, magnetic, and gravitational fields. Generated only in an electric field.

Some key points to remember:

  • EMF is the measure of energy that it gives to each coulomb of charge.
  • The electromotive force is induced in electric, magnetic, and gravitational fields, whereas the potential difference is generated only in an electric field.

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