Difference in Potential vs. Electromotive Force

Attribute	Difference in Potential	Electromotive Force
Definition	It is the difference in electric potential between two points in an electric field.	It is the energy per unit charge that is supplied by a source of electrical energy, such as a battery.
Symbol	V	ε
Unit	Volts (V)	Volts (V)
Direction	Scalar quantity	Vector quantity
Measurement	Measured between two points in an electric field	Measured as the potential difference across a source of electrical energy

Definition

Difference in potential and electromotive force are two concepts that are often confused with each other in the field of physics. Difference in potential, also known as voltage, is the measure of the electric potential energy per unit charge between two points in an electric field. It is denoted by the symbol V and is measured in volts. On the other hand, electromotive force (EMF) is the energy per unit charge supplied by a source of electrical energy, such as a battery or generator, to move a charge around a circuit. It is denoted by the symbol E and is also measured in volts.

Origin

The key difference between difference in potential and electromotive force lies in their origin. Difference in potential is a result of the presence of an electric field between two points, which causes a potential difference to exist. This potential difference is what drives the flow of electric current in a circuit. Electromotive force, on the other hand, is the force that pushes the charge carriers (usually electrons) through a circuit. It is generated by a source of electrical energy, such as a battery, and is responsible for maintaining the flow of current in a circuit.

Measurement

While both difference in potential and electromotive force are measured in volts, they are measured in different ways. Difference in potential is measured using a voltmeter, which is connected across the two points between which the potential difference is to be measured. The voltmeter measures the voltage difference between the two points and gives a reading in volts. Electromotive force, on the other hand, is measured using a device called a potentiometer. A potentiometer compares the EMF of a source with a known voltage and gives a reading in volts.

Direction

Another difference between difference in potential and electromotive force is the direction in which they act. Difference in potential always acts in the direction of decreasing potential, meaning that it flows from the point of higher potential to the point of lower potential. This is why electric current flows from the positive terminal of a battery to the negative terminal. Electromotive force, on the other hand, acts in the opposite direction. It pushes the charge carriers from the point of lower potential to the point of higher potential, maintaining the flow of current in a circuit.

Effect on Circuit

Both difference in potential and electromotive force play crucial roles in the functioning of an electrical circuit. Difference in potential is responsible for creating the driving force that moves the charge carriers through the circuit. It is what causes the flow of current from one point to another. Electromotive force, on the other hand, is what provides the energy needed to maintain this flow of current. It is the source of electrical energy that keeps the circuit running and allows electrical devices to function.

Conclusion

In conclusion, while both difference in potential and electromotive force are related to the concept of voltage and are measured in volts, they have distinct differences in terms of their origin, measurement, direction, and effect on a circuit. Difference in potential is the potential energy per unit charge between two points in an electric field, while electromotive force is the energy per unit charge supplied by a source of electrical energy to move charge around a circuit. Understanding these differences is crucial for grasping the fundamentals of electricity and how electrical circuits operate.