ray optics

Corpuscular Model of Light

A model developed by Descartes suggesting light is made of particles (corpuscles).

Refraction

The bending of light as it passes from one medium to another, changing speed.

Wave Theory of Light

A theory proposed by Huygens stating that light behaves as a wave.

Wavefront

A surface over which an oscillation has a constant phase, such as points in a wave that are at the same distance from the source.

Huygens Principle

Every point on a wavefront acts as a source of secondary waves; the new wavefront is formed by the envelope of these secondary waves.

Reflection

The change in direction of a wave when it bounces off a surface.

Snell's Law

The law relating the angles of incidence and refraction for waves passing between different media.

Constructive Interference

When two waves meet in phase, resulting in a wave of greater amplitude.

Destructive Interference

When two waves meet out of phase, resulting in cancellation.

Diffraction

The bending and spreading of waves around obstacles and through openings.

Polarization

The restriction of the vibrations of a wave to a particular direction.

Critical Angle

The angle of incidence beyond which light cannot pass through a boundary between two media and instead is completely reflected.

Electromagnetic Waves

Waves that consist of oscillating electric and magnetic fields and can travel through a vacuum.

Intensity of Light

The power carried by light waves per unit area.

Frequency

The number of complete wavelengths that pass a point in one second.

Wavelength

The distance between successive peaks (or troughs) of a wave.

Interference Pattern

The pattern created when two or more waves overlap and combine their amplitudes.