EMF measurement using potentiometer/ Measurement of EMF by Poggendorff's compensation principle

This video describes the measurement of EMF by Poggendorff's compensation principle i.e using a potentiometer. applications of emf measurement. disadvantages of measuring emf using voltmeter. experimental procedure for measuring emf is also explained.
Electromotive force (EMF) – When there is difference in potential between two electrodes, the current flows from the electrode with higher potential to the electrode with lower potential.
Measurement of EMF
Voltmeter
Multimeter
Potentiometer
Drawbacks of measuring EMF using a voltmeter
Chemical reaction occurs in the cell and some current is used during the measurement of the voltage and this alters the actual EMF.
When current flows a small portion of EMF is used to overcome the internal resistance of the cell.
There is very little or no flow of electricity in this method
Es – EMF of the standard cell
Eu – EMF of the unknown cell
AD – Balancing length of unknown cell
AD’– Balancing length of standard cell
Standard cell – Weston Cadmium cell
EMF – 1.018 V

Видео EMF measurement using potentiometer/ Measurement of EMF by Poggendorff's compensation principle канала Revathi Purushothaman