EMF:1)emf is defined as work done by the chemical force to move unit positive charge from negative terminal to positive terminal of the battery 
3)the S.I unit of emf is ''volt''
4)emf can be measured by using volt meter which is connected parallel between two terminals in a circuit.
POTENTIAL DIFFERENCE:1)work done by electric force on unit positive charge to move it through a distance 'l' from A to B is called potential difference
2)potential difference(v)=W/q=Fel/q
3)the S.I unit of potential difference is ''volt''
4)potential difference can be measured by using volt meter which is connected parallel in a circuit

This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Emf is the electromotive force. It is the potential difference across the terminals (anode and cathode) of a battery. EMF is the potential maintained by a battery and is constant during the use of the battery.

It is independent of current in the circuit. Potential difference across a battery is always in one direction from positive to negative terminal.  EMF is the source of current that drives electrons to travel in the circuit.

Potential difference across any conductor is product of current passing through it and the resistance of the conductor. It is directly proportional to the current. If the current changes direction, then potential difference will become negative or will be positive in the other direction.  A potential difference is created due to the electrons traveling in a conductor.