I am getting confused between EMF and potential difference of a cell. But i know that when a charge moves against an electric field it's potential energy increases which can be used to do some work. So can i say EMF of the cell is the work done in order to get the required potential difference between the electrodes. And if it is so can you explain the difference between PD and EMF

  • $\begingroup$ See wikipedia - Electromotive_force. You can see EMF is not work. $\endgroup$
    – Poutnik
    Nov 30, 2020 at 7:12
  • $\begingroup$ Chemistry SE site expects you to provide your elaborated results of prior thinking, analysis and searching, aside of just asking the question. Elaborated questions attract elaborated answers. The opposite may lead even to the question closure, in case of lack of the own effort. $\endgroup$
    – Poutnik
    Nov 30, 2020 at 8:10

1 Answer 1


Potential difference and EMF are equal if the galvanic cell does not produce any currant. When the cell works and produces even a small currant $I$, the potential of the cell decreases a bit, because of the internal resistance $R_i$ of the cell. If $E_o$ is the the EMP, the potential $E'$ measured between the plus and the minus poles of the working cell decreases a little bit according to Ohm's law : $E' = E_o - R_i I$

  • $\begingroup$ Currants are small dried grapes or berries. I'm not sure how galvanic cells produce them. ;-) $\endgroup$
    – matt_black
    Nov 30, 2020 at 21:06
  • $\begingroup$ @Maurice if suppose I have taken a Daniel cell and if the circuit is not complete then no current would flow. In that case we can say that the redox reaction has not taken place . So in that case i dont think there would be any potential difference between the electrodes. $\endgroup$ Dec 1, 2020 at 4:09
  • $\begingroup$ @Matt_black. OK. Thank you. Wonderful ! Next time I'll check my typing vowels, and print current instead of currant. $\endgroup$
    – Maurice
    Dec 1, 2020 at 13:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.