Chapter 7 - Optics and Wave Effects

reflection

The change in direction of a wave when it strikes and rebounds from a surface or the boundary between two media.

ray

A straight line that represents the path of light with a directional arrow.

law of reflection

The angle of reflection equals the angle of incidence, θi = θf , as measured relative to the normal, a line perpendicular to the reflecting surface.

specular reflection

Reflection from very smooth (mirror) surfaces in which the reflected rays are parallel

diffuse reflection

Reflection from a rough surface in which reflected rays are not parallel but scattered.

refraction

the deviation of light from its original path caused by a change in speed in the second medium.

index of refraction

The ratio of the speed of light in a vacuum to the speed of light in a medium

total internal reflection

A phenomenon in which light is totally reflected in a medium because of reflection

dispersion

Different frequencies of light refracted at slightly different angles, giving rise to a spectrum

focal length

The distance from the vertex of a mirror or lens to the focal point

concave (converging) mirror

A mirror shaped like the inside of a spherical section

convex (diverging) mirror

A mirror shaped like the outside of a spherical section

real image

An image from a mirror or lens for which the light rays converge so that an image can be formed on a screen

virtual image

An image from a lens or mirror for which the light rays diverge and cannot be formed on a screen

converging lens

A lens that is thicker at the center than at the edges

diverging lens

A lens that is thinner at the center than at the edges

polarization

A preferential orientation of the electric vector of a light wave

linearly polarized light

The conduction of transverse light waves that vibrate in only one plane

diffraction

The bending of waves as they go through relatively small slits or pass by the corners of objects

principle of superposition

At any time, the combined waveform of two or more interfering waves is given by the sum of the displacement of the individual waves at each point in the medium

constructive interference

A superposition of waves for which the combined waveform has a greater amplitude

destructive interference

A superposition of waves for which the combined waveform has a smaller amplitude