Electric Fields and Potential

A set of vocabulary flashcards covering key concepts in electric fields, potential, circuits, and magnetism.

Electric Flux (Φ_E)

The integral of the electric field (E) dot product with the area vector (dA), representing the amount of electric field passing through a surface.

Gauss’s Law

Φ_E = Q_encl / ε0, relating electric flux through a closed surface to the charge enclosed.

Electric Potential (U)

The work done per unit charge in bringing a charge from infinity to a point in space in an electric field.

Electric Potential Difference (V)

The difference in electric potential between two points, calculated as V_a - V_b = ∫_a^b E · dL.

Capacitance (C)

The ability of a system to store charge per unit potential difference, defined as C = |Q| / V.

Permittivity (ε)

A measure of how an electric field affects, and is affected by, a dielectric medium; ε = K ε0 for dielectric materials.

Kirchhoff's Junction Rule

The principle that the total current entering a junction equals the total current leaving the junction.

Current Density (J)

The amount of electric current flowing per unit area of a cross-section, represented as J = i/A.

Resistivity (ρ)

A material property that quantifies how strongly a given material opposes the flow of electric current; defined as ρ = E/J.

Faraday’s Law

The law stating that the induced electromotive force (ε) in any closed circuit is equal to the rate of change of the magnetic flux through the circuit.

Magnetic Flux (Φ_B)

The total magnetic field (B) passing through a surface (A), calculated as Φ_B = ∫ B · dA.

Inductance (L)

A measure of the ability of a conductor to induce an electromotive force (emf) in itself or in an adjacent conductor when the electric current changes.

Poynting Vector (S)

A vector that represents the directional energy flux (the rate of energy transfer per unit area) of an electromagnetic field.

Ohm’s Law

The relationship between voltage (V), current (I), and resistance (R) in a circuit, expressed as V = iR.

Standing Waves

Waves that remain in a constant position, typically formed by the interference of two traveling waves moving in opposite directions.

LC Circuit

An electric circuit consisting of an inductor (L) and a capacitor (C) which can oscillate with specific resonant frequencies.

Magnetic Force on a Moving Charge

The force experienced by a charged particle moving through a magnetic field, calculated as F = q(v × B).

Cyclotron Frequency

The frequency at which a charged particle orbits in a magnetic field, defined as f = (qB)/(2πm) where B is the magnetic field strength.

Intensity of Radiation (I)

The power per unit area carried by a wave, often calculated in relation to the amplitude of the electric field.

Critical Angle (φ_critical)

The angle of incidence above which total internal reflection occurs, given by φ_critical = arcsin(n2/n1) in optics.

Lens Maker's Formula

A formula used to determine the focal length of a lens based on the radii of curvature of its surfaces and its refractive index.