CHAPTER 10. COLOUR 10.4
Chapter 10 — Summary
See the summary presentation ( Presentation: VPqyc at http://www.everythingscience.co.za)- Different colours of light correspond to different frequencies or wavelengths.
- The wave equation c = fλ allows us to specify the relationship betweenfre-
quency and wavelengthas c is a constant 3 × 108 m· s−^1. - The primary colours are red, green and blue,all other colours can beformed
using combinations of these. - An object of a specificcolour actually reflects light of that colour. Pigments and
paints are substances that absorb certain colours(frequencies) of light andreflect
others to give an objecta specific colour. - Opaque objects or materials do not allow visible light to pass through them. You
cannot see through them. - Transparent objects ormaterials do allow visible light to pass through.You can
see through them.
Chapter 10 End of Chapter Exercises
- Calculate the wavelength of light which has afrequency of 570 × 1012
Hz. - Calculate the frequency of light which has a wavelength of 580 nm.
- Complete the following sentence: When white light is dispersed by a
prism, light of the colour ... is refracted the most and light of colour
... is refracted the least. - What are the two types of photoreceptor found in the retina of the
human eye called and which type is sensitive tocolours? - What colour do thefollowing shirts appearto the human eye when
the lights in a room areturned off and the roomis completely dark?
(a) red shirt
(b) blue shirt
(c) green shirt - Two light bulbs, eachof a different colour, shine on a sheet of white
paper. Each light bulb can be a primary colourof light - red, green,
and blue. Depending on which primary colourof light is used, the
paper will appear a different colour. What colour will the paper ap-
pear if the lights are:
(a) red and blue?
(b) red and green?