Question

When one can notice the phenomenon of diffract of light ?

Answer 1

When a multicolored light-white goes through vaccum or air all the rays have same velocity, but when they are passing through a medium of higher refracting index than vaccum or air, they got diffraction due to their various wavelengths. Red light has shorter wavelength, higher frequency, so they get a minimum diffraction where violet get a great diffraction due to its high wavelength and low frequency.