Electrostatics: Coulomb's Law, Electric Field, and Electric Potential

Study Notes

Electrostatics

Coulomb's law states that the electric force between two charged points (q1 and q2) is inversely proportional to the square of the distance between them.
The electric force is given by F = K.(q1 q2)/r^2, where F is in Newtons.
Electric field is the region surrounding a charged particle or group of charges where another charged particle experiences a force of attraction or repulsion.
The electric field strength is given by E = K.q/r^2, where E is in Newtons per Coulomb.
Electric potential is the difference in potential between two points and is the work done against the electric field.
The electric potential is given by V = K.q/r, where V is in Volts.

Gauss's Law

Gauss's law states that the electric flux across any closed surface is proportional to the net electric charge (q) enclosed by the surface.
The electric flux is given by ϕ = q/Є_0.

Magnetism

A magnetic field is produced around a conductor when a current passes through it.
The magnetic flux density at a wire is given by B = (µ_0 i)/2πr.
The magnetic flux density is a measure of the magnetic field strength.
The magnetic flux is the region around a magnet where the force of attraction or repulsion can be detected by a magnetic compass.
The magnetic flux is given by ∅ = B.A, where ∅ is in Webers.

Faraday's Law and Lenz's Law

Faraday's law states that a changing magnetic field induces a potential difference in a coil and produces an induced current.
The electromotive force (emf) is given by emf = -dϕ/dt.
Lenz's law states that an induced current always flows in a direction such that it opposes the change that produced it.
The electromotive force is given by ɛ = (dϕ_b)/dt.

Magnetic Flux Density

The magnetic flux density for the center of a circular coil is given by B = (µ_0 iϕ)/4πr.
The magnetic field produced by a circular coil appears as concentric circles around the conductor, with the arcs of the circles becoming larger and appearing as straight lines towards the center.

Description

Understand the fundamental concepts of electrostatics, including Coulomb's law, electric field, electric potential, and Gauss's law. Learn how to calculate electric force, electric field, and electric potential.