What is the difference between Electro-Motive-Force and Potential-Difference?

Electro-Motive-Force (EMF) and Potential Difference (PD) are two concepts related to electricity. While they are similar in some ways, there are some key differences between them.

Electro-Motive-Force (EMF) is a term used to describe the electrical potential difference across a complete circuit or device when no current is flowing. It is often represented by the symbol E. EMF is a measure of the total energy supplied to the charges as they move around the circuit. It can be thought of as the force that pushes the charges through the circuit.

On the other hand, Potential Difference (PD), also known as Voltage, is a measure of the electric potential energy difference per unit charge between two points in a circuit. It is often represented by the symbol V. Potential Difference is the difference in electric potential between two points that causes the charges to flow from one point to another. PD is responsible for the movement of charges in a circuit and is directly related to the flow of current.

To measure EMF, a high-impedance voltmeter is connected across the terminals of the circuit or the device under consideration. The voltage measured will be the EMF of the circuit or the device.

To measure PD, a voltmeter is connected across the two points in a circuit between which the potential difference is to be determined. The reading on the voltmeter will represent the potential difference between those two points.

In summary, the main difference between EMF and PD is that EMF represents the total energy supplied to the charges in a circuit, while PD represents the energy difference per unit charge between two points in a circuit. Both EMF and PD are important concepts in understanding the behavior of electricity in circuits.