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4 August 2019

Difference between potential difference and EMF

We all know that the potential difference and electromotive force both in the form of energy. One of the major key difference between P.D and EMF is that the EMF is caused by converting the other form of the energy into electrical energy whereas in P.D is the difference the electrical energy is converted into other forms of energy some of the major difference is given below.

If you want to learn some different you are the right place for reading so keep reading for a few minutes for the right information regarding P.D and EMF.

Definition of Potential Difference :


The potential difference is defined as the amount of energy can be used to moving from one point to another by one coulomb of charge. It is the measurement in volt and represented by the symbol of V. 

Definition of EMF : 


Electromotive force: The EMF is the total voltage induced by the source. It is also the amount of energy supplied by the source to each coulomb of charge, It is measured in volts and represented by an E.

Difference between P.D and EMF : 

  • EMF stands for electromotive force while P.D stands for potential difference.
  • Potential difference is the difference of potentials between any two points in a closed circuit while EMF is the maximum potential difference between the two electrodes of the cell when no current drawn from the cell.i.e  when the circuit is open.
  • P.D is the amount of energy used by the one coulomb of change while EMF force is the measure of the energy that it gives to each Colomb of change.
  • P.D is the effect while EMF is the cause.
  • P.D is a symbol of V, while EMF is the symbol of E.
  • P.D does not remain constant, EMF remain constant.
  • P.D is proportional to the resistance between the given point, EMF is independent of the resistance of the circuit.
  • P.D is measured between any two points of the circuit while EMF is used only for the source of EMF.
  • P.D is greater than EMF when the cell is being charged while EMF is greater than the potential difference between any two points in a circuit.
  • P.D is less than the maximum voltage obtainable current from the cell, EMF is the maximum voltage that can be obtained from the cell.
  • P.D is not responsible for the flow of steady current in the cell, EMF is responsible for the flow of steady current in the cell.
  • P.D is represented by the voltmeter reading in a closed circuit(when the circuit is closed) while in EMF is represented by the voltmeter reading in an open circuit(when the switch is opened).
  • A voltmeter is used for measuring the P.D while EMF meter is used for measuring the electromotive force.
  • P.D  = E - IR, R= total external resistance while EMF (E) = I(R+r), R+r = Total external resistance and total internal resistance, I = total current
  • Bothe P.D and EMF  are measured in volts(V). 
  • P.D loses the electrical energy in the circuit, EMF force gains the electrical energy in the circuit.
  • P.D is directly dependent on the resistance between two points of measurement while EMF does not depend on circuit resistance.
  • P.D  is generated only in an electric field, EMF  is induced in the electric, magnetic and gravitational field.
  • P.D is always less than the maximum possible value of EMF, EMF is the maximum voltage that battery can deliver whereas the magnitude of the P.D.
  • P.D does not exist in the circuit when the magnitude of current remains zero while the EMF force exists in the circuit when the current does not flow in the circuit.
  • The magnitude of the potential difference varies while the magnitude of EMF has always remained constant.
  • The magnitude of electromotive force is always greater than potential difference when the circuit is unchanged but when the circuit is fully charged the magnitude of the potential difference is equal to the EMF of the circuit.
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