DISPERSION OF LIGHT

Dispersion of Light:

It is found that when a beam of Sunlight  ( generally called white light) passes through a glass prism, the emergent light consist of several colours. There is continuously varyring colours as VIOLET, INDIGO, BLUE, GREEN, YELLOW, ORANGE,RED. We can use an acronym VIBGYOR for above colours. The red light bends the least while the violet bends most, as the refractive index works differently for different wavelengths and The red colour has maximum wavelength and violet has minimum in visible range. These colours are the constituent colours of white light.

        

                 Fig : Dispersion of Light

The phenomenon of Splitting of white light into its component colours when passing through a Prism is called Dispersion of light.

This pattern of colour components of light is known as spectrum of light.

An experiment was done by Isaac Newton to show that these colours are the components of white light. He put a similar prism just after the emergent light from one prism but in an inverted situation as shown in figure.

         

   Fig : Newton's experiment on dispersion of white light

The final emergent light is again a white light, which shows that these colours are components of white light. When white light passes through prism, it splits up into its constituent colours and when these splitted colours again pass through an inverted prism, they recombine to form a white beam .