Electric flux

Electric flux measures the electric field passing through a surface by integrating the field component perpendicular to it over that surface. Its value depends on the field, the surface’s area, and its orientation.

Electric field: A vector field that assigns each point the electric force per unit positive test charge. Flux integrates this field’s component perpendicular to each surface element.
Electric charge: A fundamental property of matter that produces and responds to electromagnetic interactions. Charges are sources and sinks of the electric fields whose flux is measured.
Gauss's law: A law stating that net electric flux through a closed surface equals enclosed charge divided by permittivity. It connects closed-surface flux to charge without requiring the field at every point.
Magnetic flux: The surface integral of the magnetic field’s component normal to a surface. It has the same mathematical form, but measures magnetic rather than electric fields.
Surface integral: An integral that accumulates a quantity distributed over a surface. Electric flux is computed by integrating the normal field component across the surface.
Gaussian surface: An imaginary closed surface used to apply Gauss’s law. Closed Gaussian surfaces make total electric flux directly comparable to enclosed charge.
Electric displacement field: A field used in macroscopic electromagnetism to represent free charge and polarization effects. Its flux through a closed surface counts enclosed free charge.
Electric potential: Potential energy per unit charge at a point in an electric field. Potential is a scalar at a point; flux measures a field across a surface.
Area vector: A vector normal to a surface whose magnitude equals the surface’s area. Its direction encodes surface orientation in the dot-product form of flux.
Electric field line: A curve whose tangent at each point gives the direction of the electric field. Field lines crossing a surface provide a visual picture of its flux.

Linked from 9 pages