light

• what is the angle between the incoming wave and the normal?

  angle of incidence
• what is the angle between the reflected wave and the normal?

  angle of reflection
• what is specular reflection?

  when waves are reflected in a single direction by a smooth surface
• what is diffuse reflection?

  when waves are reflected by a rough surface, and the waves are reflected in all directions
• what is total internal reflection?

  the wave is reflected back into the material
• when does a wave experience total internal reflection?

  when the wave travels through a dense material towards a less dense substance
• what happens when light is reflected by something rough?

  the surface looks matt, and you don't get a clear reflection
• which colour has the longest wavelength?

  red
• which colour has the highest frequency?

  violet
• which colour reflects all of the wavelengths of visible light equally?

  white
• which colour absorbs all wavelengths of visible light?

  black
• what is the shape of a converging lens?

  bulges outwards in the middle
• what is the shape of a diverging lens?

  caves inwards
• what is the principal focus of a converging lens?

  where rays hitting the lens parallel to the axis all meet
• what is the principal focus of a diverging lens?

  where rays hitting the lens parallel to the axis appear
• what is the focal length?

  the distance from the centre of the lens to the principle focus
• what is another name for a converging lens?

  convex lens
• what is another name for a diverging lens?

  concave lens
• when is a real image formed?

  when the light rays actually come together to form the image
• when is a virtual image formed?

  when the light rays from the object appear to be coming from a completely different place to where they are actually coming from. The light rays don't actually come together
• what is an example of a real image?

  image formed on the eye's retina
• what is an example of a virtual image?

  image created by a magnifying glass