wave

Absolute Index of Refraction

The ratio of the speed of light in a vacuum to the speed of light in a medium, given by the formula: $n = \frac{c}{v}$.

Amplitude

The maximum displacement of a particle of the medium from the rest position; related to intensity.

Angle of Incidence

The angle at which an incident light ray strikes the surface of a medium, measured relative to a normal (perpendicular) to the surface.

Angle of Reflection

The angle at which a light ray is reflected from a surface, always equal to the angle of incidence.

Angle of Refraction

The angle at which a light ray is refracted from a surface of a medium, measured relative to a normal (perpendicular) to that surface.

Antinode

A point on a standing wave with the greatest displacement from the rest position, where maximum constructive interference occurs.

Apparent Frequency

The frequency perceived by an observer when the wave source is moving relative to the observer, as described in the Doppler Effect.

Coherent Light Source

A source of light producing waves with a constant phase relationship; lasers are an example.

Constructive Interference

The effect of combining two waves in the same direction where the wave crests and troughs reinforce each other, resulting in increased amplitude.

Critical Angle

The smallest angle of incidence at which total internal reflection occurs when light passes from one medium to a less refractive medium.

Cycle

One complete pattern of a wave or other periodic phenomenon.

Destructive Interference

The effect of combining two waves in opposite directions where the wave crests diminish each other, leading to a reduced amplitude.

Diffraction

The spreading or bending of a wave into a region behind an obstacle.

Diffuse Reflection

The scattering of light caused by reflection from an irregular surface.

Dispersion

The process of separating multicolored rays of light into their constituent colors.

Doppler Effect

The variation in observed frequency caused by the relative motion between a source and a receiver.

Electromagnetic Spectrum

A broad range of electromagnetic waves including radio waves, infrared waves, visible light, ultraviolet waves, x-rays, and gamma rays.

Frequency

The number of vibrations occurring per unit of time, with the SI unit being hertz (Hz).

Hertz (Hz)

The SI unit of frequency, defined as one cycle per second.

Image

An image formed when light rays from the same point intersect on a surface or appear to intersect to an observer.

Incident Ray (Wave)

A light ray or wave that strikes a surface.

Index of Refraction

A measure of how much light is refracted when it moves between different optical media, related to the angles of incidence and refraction.

Interface

The boundary between two surfaces.

Interference

The effect produced by two or more waves passing simultaneously through a region.

Laser

A device generating electromagnetic radiation via stimulated emission of photons.

Law of Reflection

The principle that the angle of reflection equals the angle of incidence.

Longitudinal Wave

A wave in which the vibratory disturbance is parallel to the direction of wave travel, like sound waves.

Mechanical Wave

A wave that requires a material medium to carry the wave energy.

Medium

A material through which a disturbance travels.

Monochromatic Light

Electromagnetic radiation that includes only a narrow range of frequencies.

Natural Frequency

The frequency at which an elastic object vibrates when disturbed.

Node

A point on a standing wave with almost no vibration, where maximum destructive interference occurs.

Normal

A reference line drawn perpendicular to a surface, used for measuring angles of incidence, reflection, and refraction.

Optical Density

A measure of the opaqueness of a translucent medium; denser mediums slow down light.

Period

The time required for the completion of a single vibration or event of a periodic phenomenon.

Phase (Wave)

Points on a periodic wave having the same displacement and moving in the same direction are said to be in phase.

Plane Mirror

A flat reflecting surface creating an image that is virtual and erect.

Polarization

The separation of a beam of light so that its vibrations are in the same plane.

Polychromatic Light

Light made up of multiple wavelengths.

Prism

An optical device that disperses light into its component wavelengths.

Refraction

The change in direction of a wave as it passes at an angle through a boundary between two different media.

Regular Reflection

Reflection from smooth surfaces producing a clear image of the source.

Resonance

Vibrations in an object at its natural frequency caused by a wave with the same frequency.

Snell's Law

The relationship between angles of incidence and refraction: $n_1 \sin(\theta_1) = n_2 \sin(\theta_2)$.

Standing Wave

Produced when two waves of the same frequency and amplitude travel in opposite directions in the same medium.

Superposition

A combination of two or more wave displacements to produce a resultant displacement.

Total Internal Reflection

Reflection of light inside a dense medium occurring when the angle of incidence exceeds the critical angle.

Transverse Wave

A wave in which the disturbance is perpendicular to the direction of wave travel, as in light waves.

Wave

A vibratory disturbance that propagates through a medium or space, transferring energy without mass transfer.

Wave Characteristics

Properties of waves defining their behavior, including period, frequency, amplitude, and wavelength.

Wave Front

The locus of points of a wave that are in phase.

Wavelength

The distance between two consecutive points in phase on a wave.