Activity - I:
- Select a white coated wall on which the sun rays fall.
- Stand in front of a wall in such a way that the sun rays fall on your back.
- Hold a tube through which water is flowing.
- Place your finger to obstruct the flow of water.
- Water comes from small gaps between the tube and figures like a fountain.
- Observe the changes on wall while showering the water.
Activity - II:
- Take a metal tray and fill it with water.
- Place a mirror in water such that it makes an angles with water surface.
- Now focus white light on the mirror through the water.
- Keep a white card board sheet above the water surface as shown in figure.
- We may 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.