A simple arrangement by means of which EMF are compared is known as a voltmeter.
Discussion about Voltmeter :
A voltmeter is a straightforward device used to compare electromagnetic fields.
When there is no current flowing through a cell, its terminal voltage equals its electromotive force (emf). The difference in potential between a cell's electrodes is what determines its terminal voltage. Since voltmeters use the cell's current to draw voltage, they are unable to measure a cell's emf.
Using a voltmeter, one may determine the voltage generated in an electric circuit. Volts are the emf's SI unit (V). Volts are the voltage's SI unit (V). Non-coulomb force, also known as non-electric force operation, defines emf.