What is “dispersion of white light” ? Draw a labelled diagram to illustrate the recombination of the spectrum of white light. Why it is essential that the two prisms used for the purpose should be identical and placed in an inverted position with respect to each other?
The splitting of white light into seven colours on refraction is called dispersion of light.
The dispersion of white light occurs because colours of white light travel at different speeds through the glass prism. The amount of refraction depends on the speed of coloured light in glass.
The two prisms should be identical because if they are different, their refractive index would be different resulting in further dispersion and not recombination. If the prisms are identical then both have equal and opposite refractive index which would help in recombination. Prisms are inverted so that from first prism the lights will get diverged and from the second it will converge.
