Flux is a physical quantity that represents the amount of a field passing through a surface. It provides a way to quantify how much of something—like an electric or magnetic field—“flows” across a given area. Flux is a key concept in fields such as electromagnetism and fluid dynamics.
There are two main types of flux in electromagnetism:
- Electric flux: Measures the number of electric field lines passing through a surface. It’s directly related to the amount of electric charge enclosed (as per Gauss’s Law).
- Magnetic flux: Measures the number of magnetic field lines passing through a surface. It’s crucial in Faraday’s Law, where a changing magnetic flux induces an electromotive force (EMF) in a loop.
Mathematically, flux is calculated as the dot product of the field vector and the area vector, considering both the field strength and the orientation of the surface.
Flux is essential for understanding how fields interact with surfaces in:
- Electric circuits (e.g., in transformers and inductors),
- Generators and motors,
- Electromagnetic theory and Maxwell’s equations,
- Gauss’s and Faraday’s laws in integral form.
By measuring how much of a field penetrates a surface, flux helps connect physical laws with real-world effects in fields and forces.