Question

When we invert the prism the order in which the seven colours come out is also reversed, how does this happen?

Answer 1

According to Issac Newton when white light passes through a prism it splits into seven colours and comes out at different angles, red at least angle and violet at a maximum angle following the formula deviation directly proportional to refractive index and refractive index inversely proportional to the square of wavelength. If we take the second prism-like first prism then the different deviated colours from the first prism will again deviate forming circular rings but no further colour is obtained. If we take the second prism inverted, the deviated colours from the first prism will again deviate by the second prism towards base giving white light.