2. Electromagnetic spectrum Light is just a small part of the electromagnetic spectrum. Microwaves, infra-red radiation and x-rays are other parts. The various types of electromagnetic waves are different because they very in energy and the size of their wavelengths. The shorter the wavelength the higher its energy and the more harmful it is to living organisms. For example gamma radiation has a very short wavelength and if humans are exposed to it DNA mutation and cell destruction occurs, like that which occurs from high nuclear radiation exposure. Although visible light travels in waves it also travels in a straight line.

3. Law of Reflection Light ray hitting a mirror or smooth reflective surface bounces off at the same angle it struck the surface. By doing this it has obeyed the Law of Reflection. Both angles may be measured by drawing an imaginary line down the middle of the incident ray and the reflected ray, which is called the normal. The two angles always remain equal despite how the light rays strike the surface.

4. Law of Reflection and Curved Mirrors The law of reflection remains true for curved mirrors (concave and convex) When rays reflect off a concave mirror the rays converge at a point called the focus. The focal length is measured from the reflective surface to the focus. Concave mirrors inverts and shrinks the real image. Where convex mirrors create an enlarged virtual image.