Physics Grade 12
Unit 5: Waves
Note 7: Colour and Wavelength
Reference: Chapter 9.6
Knowing that red light has a longer wavelength than blue light, which do you think has a greater separation of nodal lines?
See page 476 and notice red light has a greater separation of nodal lines than blue light. This is because red light has a longer wavelength.
Recall that:
In some media (Dispersive media) the velocity is dependent on the wavelength of the light (i.e. a prism). White light is made up of all colours. If white light passes through a prism, its different frequencies are refracted (bent by different amounts) and we have dispersion. Shorter wavelengths (higher frequencies) are refracted more than longer wavelengths.
The prism's glass has a different index of refraction for each colour and therefore different colours travel at slightly different speeds in the glass.
Recall :
Text:
Page 478 # 5,6
Page 479 #4-6