Difference Between EMF and Potential Difference

By Aina Parasher|Updated : April 28th, 2022

Difference Between EMF and Potential Difference:  Both EMF and potential difference are measured in volts but there is a huge difference in their meaning. The main difference between EMF and potential difference is that the energy per unit charge exerted by an energy source is known as the EMF whereas the energy released when a unit quantity of electricity travels from one spot to another is known as the potential difference.

EMF or electromotive force is referred as the terminal potential difference when no current flows. In the coming sections, we will see what are EMF and potential difference along with finding the difference between emf and potential difference. 

Table of Content

What is EMF (E)?

The full form of EMF is electromotive force. The characteristic of any energy source capable of pushing electric charge around a circuit is called electromotive force or EMF, which is the force inside a voltage source that drives current around a circuit. The electromotive force or EMF is the amount of energy provided by a cell to the unit charge. It is denoted by E.

Regardless of the energy source, all of these devices produce potential differences across their terminals and may deliver current when resistance is attached to them. It is well understood that a potential difference produces an electric field, which causes charges to move and, in turn, current to flow. Thus, the potential difference generated when no current is flowing is known as EMF. 

What is the Potential Difference (V)?

When a coulomb flows from one point to another, the potential difference, or voltage, is simply an indication of how much potential energy is gained or lost per coulomb. It's also known as the amount of work required to move potential energy per coulomb from one spot to another.

The energy released in the movement of a unit quantity of electricity from one place to the other is represented by the potential difference between two points in an electrical or electronic circuit. It is denoted by V.

The important thing to understand is that EMF is the driving force, whereas the potential difference is the outcome of EMF. Further, let us now check the difference between these two.

Difference Between EMF and Potential Difference

As we have discussed EMF and potential difference in the sections above. Here, we have provided the difference between EMF and potential difference listed in the table below.

EMF VS Potential Difference
EMF Potential Difference
The quantity of energy delivered to each coulomb of charge is known as the electromotive force. One coulomb of charge expends a certain amount of energy, which is called the potential difference.
The unit of EMF is Volt.The unit of potential difference is Volt.
It is independent of resistance.It depends upon resistance between two points.
It is measured using an emf meter.It is measured using a voltmeter.
The electric, gravitational, and magnetic fields are responsible for this.The electric field is the sole source of potential difference.

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FAQs

  • The main difference between EMF and potential difference is that emf is the quantity of energy delivered to each coulomb of charge whereas, the potential difference is a certain amount of energy one coulomb of charge utilizes.

  • The full form of EMF is the electromotive force which is equal to the terminal potential difference when no current flows. This potential difference is created by altering the magnetic field or by using an electrochemical cell.

  • Based on resistance, the difference between EMF and potential difference is-

    • The electromotive force is unaffected by the internal resistance of the circuit.
    • The potential difference is proportional to the resistance of a circuit.
  • The external work required to move a charge from one position to another in an electric field is known as the electric potential difference, or voltage. It is represented by V.

  • The external work required to move a charge from one position to another in an electric field is known as the electric potential difference, or voltage. The change in potential energy experienced by a test charge with a value of +1 is known as the electric potential difference.

  • Both EMF and potential difference are measured by different instruments. EMF is measured using an emf meter whereas, the potential difference is measured using a voltmeter.

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