Visible light and colour

What is visible light made up of?

A wide spectrum of colours (rainbow)

How is white light made?

A combination of all the wavelengths

How is black made?

An absence of light.

Why do objects appear the colour they do?

The wavelengths of the light hitting it and the properties of the object, together these determine which light rays are absorbed, transmitted and reflected.

What are opaque objects?

Objects that don’t emit any light, all the wavelengths of light are either absorbed or reflected.

Why are objects transparent?

They transmit nearly all the light and only a small fraction is absorbed or reflected.

Why are objects translucent?

They only transmit some of the light, the proportion of light they transmit determines how well we can see through them.

How do colour filters work?

By transmitting only certain wavelengths, whilst absorbing the rest.

What is specular reflection?

Also known as regular reflection, it is the mirror like reflection of waves such as light from a surface.

What is diffuse reflection?

The reflection of light or other waves or particles from a surface that array incident on the surface is scattered at many angles rather than just one angle as in the case of specular reflection.