- Take a metal tray and fill it with water.
- Place a mirror in the water such that it makes an angle with water surface.
- Now focus white light on the mirror through the water as shown in figure.
- Keep a white card board sheet above the water surface.
- We can observe the colours VIBGYOR on the board.
- The splitting of white light into different colours (VIBGYOR) is called dispersion.
- So consider a white light is a collection of waves with different wavelength.
- Violet has shortest wavelength and red has longest wavelength.