Reflection and Refraction

S- size

A- attitude

L- location

T- type

refraction: phenomenon that often occurs when waves travel from a medium with a given refractive index to a medium with another at an oblique angle. At the boundary between the media, the wave's phase velocity is altered, usually causing a change in direction.

The Law of Reflection:

When a ray of light strikes a plane mirror, the light ray reflects off the mirror. Reflection involves a change in direction of the light ray. The convention used to express the direction of a light ray is to indicate the angle which the light ray makes with a normal line drawn to the surface of the mirror. The angle of incidence is the angle between this normal line and the incident ray; the angle of reflection is the angle between this normal line and the reflected ray. According to the law of reflection, the angle of incidence equals the angle of reflection.

concave mirror: diagram showing the focus, focal length, centre of curvature, principal axis, etc. A concave mirror, or converging mirror, has a reflecting surface that bulges inward (away from the incident light). Concave mirrors reflect light inward to one focal point.They are used to focus light.

Diverging Lens: lens that causes a beam of parallel rays to diverge after refraction, as from a virtual image; a lens that has a negative focal length. Also called negative lens. Compare converging lens.

converging lens: (or convex lens) is curved on both sides. This means the light rays coming out of it come together at a point – they converge. Diagram of how a lens works. The point at which the light rays meet is called the focal point.