Electric Field and Gauss’s Law

Electric Field

Developed by Michael Faraday in the context of electric forces.

Action-at-a-distance force

Force acting through empty space without the need for any matter, similar to gravity.

Test charge

A charge (q0) placed in an electric field to experience a force.

SI unit of Electric Field (E)

[N/C]

Electric Field Lines

Lines that begin on a positive charge, end on a negative charge, and never cross.

Superposition of Electric Fields

The vector sum of electric fields caused by individual charges.

Electric Flux

Analogous to the velocity vector of a fluid in motion; the flow of an electric field through a surface.

Gauss's Law

Relates the distribution of electric charge to the resulting electric field using symmetry considerations.

Flux of a Point Charge inside a Spherical Surface

Zero if the charge is enclosed.

Qualitative Statements of Gauss's Law

1. Outward or inward electric flux through a closed surface depends on the sign of the enclosed charge. 2. Charges outside the surface do not contribute to electric flux. 3. Net electric flux is proportional to the size of the closed surface.