Resources | Subject Notes | Physics
This section focuses on understanding electromotive force (e.m.f.) and potential difference (p.d.), particularly the unit of measurement for electromotive force.
Electromotive force is the energy supplied by a source to each unit charge.
It is essentially the driving force that causes electric charges to flow in a circuit.
e.m.f. is measured in units of volts (V).
Potential difference is the difference in electric potential between two points in a circuit.
It represents the work done per unit charge to move charges between the two points.
Potential difference is also measured in units of volts (V).
In an ideal circuit, the electromotive force (e.m.f.) of a source is equal to the potential difference (p.d.) across its terminals.
This is true for a simple source like a battery.
The unit of measurement for both electromotive force and potential difference is the volt (V).
One volt is defined as one joule of energy per coulomb of charge.
$$1 \text{ Volt} = 1 \frac{\text{Joule}}{\text{Coulomb}}$$
| Quantity | Symbol | Unit | Description |
|---|---|---|---|
| Electromotive Force | $E_{m.f.}$ | Volt (V) | The energy supplied by a source to each unit charge. |
| Potential Difference | $V$ | Volt (V) | The difference in electric potential between two points. |
Understanding that e.m.f. is measured in volts is a fundamental concept in electricity and is crucial for analyzing circuits.