Year 9 Light and colour Homework

Name: ______

  1. Use these words:
    absorbs,refraction, reflected, energy, wavelengths, prism, colours

Light is a form of ______that mostly behaves like a wave.

White light is made up of different ______.
Different wavelengths give different ______.

You can see the different colours of the rainbow when light passes through water droplets or a glass triangular ______. The different wavelengths bend differently through the water or the glass, which separates the colours. This is called ______. Colour the diagram!

2. You see different colours according to the wavelengths of light that are absorbed or ______from the object you are looking at. For example, a ripe tomato looks red because it reflects the red wavelength of light back to your eyes and ______the other colours.

3.Match the sentence halves by drawing a line between them.

a A rainbow is made when / • the least when passing through the prism.
b Red light bends / • it absorbs all light wavelengths except green.
c Violet light bends / • light passes through water droplets and refracts into its different wavelengths.
d A lemon looks yellow because / • the most when passing through the prism.
e Grass looks green because / • it reflects the yellow light back to our eyes.

The surface of the apple is reflecting the wavelengths we see as red and absorbing all the rest. An object appears white when it reflects all wavelengths and black when it absorbs them all.

Red, green and blue are the additive primary colours of the colour spectrum. Combining balanced amounts of red, green and blue lights also produces pure white. By varying the amount of red, green and blue light, all of the colours in the visible spectrum can be produced.

4. A white box of photographic paper has been written on in large red letters. The box of paper is in a photographic darkroom where the only light is from a RED lamp.
a) What colour does the white box appear
b) What colour does the red writing appear
c) The red lamp is now switched off and a green lamp is switched on.
(i)What colour does the red writing appear in the green light?
(ii)Explain why the writing will appear this colour?

  1. Name that process that split the white light into different colour. Write down the names of the seven colours of a rainbow, in the right order.
  2. When white light is passed through a prism, which colour of light is refracted the most?
  3. When you shine white light into a blue filter:

(a) which colour passes through the filter?

(b) what happens to the other colours?

  1. In terms of the light falling on it;

(a) why is this ink black?

(b) why is the paper white?