Q. When exposed to sunlight, thin films of oil on water often exhibit brilliant colours due to the phenomenon of

 2200  204 AIIMSAIIMS 2005Wave Optics Report Error

Solution:

When a thin film of oil spreads over the surface of water and it is seen in broad day light, brilliant colours are seen. There colours arise due to interference of sun-light reflected from the upper and lower surfaces of the film.
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While bending of light rays at curvatures of obstacles is called diffraction. Dispersion is splitting of white light and polarisation is the restriction of the vibrations in a transverse wave.