Electromotive force, also known as EMF, is a measure of the energy that is generated by a source, such as a battery or generator, that drives an electric current through a circuit.
Electromotive force is typically measured in units of volts (V) using a voltmeter. This instrument measures the potential difference between two points in a circuit, which is essentially the force that is driving the flow of electrons.
The value of electromotive force can be affected by factors such as the type of material used to create the source (e.g. a battery), the temperature, and the resistance of the circuit.
EMF and potential difference are closely related, as they both measure the force that drives the flow of electrons in a circuit. However, EMF is the total energy generated by the source, while potential difference is the difference in energy between two points in the circuit.
The formula for calculating electromotive force is EMF = I × R, where I is the current flowing through the circuit and R is the total resistance of the circuit. This formula is known as Ohm's law and is used to determine the force that is driving the flow of electrons in a circuit.