Electrostatics Vocabulary

Flashcards for reviewing key vocabulary from the Electrostatics unit, covering historical background, basic properties of charges, Coulomb's law, electric fields, and more.

Electrostatics

The branch of electricity that deals with stationary charges.

Amber

A solid, translucent material formed from the resin of a fossilized tree; observed by the Greeks to attract small objects when rubbed.

Triboelectric charging

Charging objects through rubbing.

Electric charge

The property of particles that causes them to experience forces when placed in an electromagnetic field; SI unit is Coulomb (C).

Conservation of charges

The principle stating that total electric charge in the universe is constant and charge can neither be created nor be destroyed.

Quantisation of charges

The principle stating that the charge q on any object is equal to an integral multiple of the fundamental unit of charge e (q = ne).

Coulomb's Law

The electrostatic force between two stationary point charges is directly proportional to the product of the magnitude of the two point charges and inversely proportional to the square of the distance between them.

k (in Coulomb's Law)

The constant that appears in Coulomb's law, with a value of approximately 9 × 10^9 N m^2 C^–2 in SI units.

ε₀ (Epsilon naught)

The permittivity of free space or vacuum, with a value of approximately 8.85 × 10^–12 C^2 N^–1 m^–2.

Relative permittivity (εᵣ)

The permittivity of a medium divided by the permittivity of free space (εᵣ = ε/ε₀).

Superposition principle

The principle stating that the total force acting on a given charge is equal to the vector sum of forces exerted on it by all the other charges.

Electric Field Intensity (Electric Field)

The force that would be experienced by a unit positive charge placed at that point; SI unit is Newton per Coulomb (N/C).

Electric field lines

Visual representation of the electric field in some region of space.

Uniform electric field

A region where the electric field has the same direction and constant magnitude at all points in space.

Non-uniform electric field

A region where the electric field has different directions or different magnitudes (or both) at different points in space.

Electric dipole

Two equal and opposite charges separated by a small distance.

Electric dipole moment

A vector quantity that measures the strength and direction of an electric dipole; SI unit is coulomb meter (Cm).

Equipotential Surface

The surface on which all points are at the same electric potential.

Relation between Electric Field and Potential

The electric field is the negative gradient of the electric potential.

Electric flux

The number of electric field lines crossing a given area kept normal to the electric field lines; SI unit is N m^2 C^–1.

Gaussian surface

An imaginary surface enclosing a charge distribution, used to calculate electric flux.

Gauss Law

The law stating that the total electric flux through a closed surface is proportional to the charge enclosed (ΦE = Q/ε₀).

Electrostatic equilibrium

The condition where there is no net current in the conductor.

Electrostatic shielding

The phenomenon where the electric field inside a cavity within a conductor is zero, regardless of external electrical disturbances.

Electrostatic induction

Charging a conductor without any direct contact with a charged object.

Action of points (Corona discharge)

The tendency for charge to accumulate at sharp points or edges on a conductor, leading to a high electric field and ionization of surrounding air.

Lightning arrester (Lightning conductor)

A device used to protect tall buildings from lightning strikes, based on the principle of action at points.

Van de Graaff Generator

Is a device which produces a large amount of electrostatic potential difference, up to several million volts (107 V).

Dielectric (Insulator)

A non-conducting material that has no free electrons and becomes polarized when an external electric field is applied.

Polarisation

The total dipole moment per unit volume of the dielectric.

Dielectric strength

The maximum electric field a dielectric can withstand before it breaks down and starts to conduct electricity.

Capacitor

A device used to store electric charge and electrical energy; typically consists of two conducting objects separated by a distance.

Capacitance

The ratio of the magnitude of charge on either of the conductor plates to the potential difference existing between them (C = Q/V); measured in Farads (F).