question_answer

What two main changes in diffraction pattern of single slit will you observe when the mono-chromatic source of light is replaced by a source of white light ?                                

Answer:

                When the monochromatic source is replaced by a source of white light, the diffraction pattern shows following changes: (i) In each diffraction order, the diffracted image of the slit gets dispersed into component colours of white light. As fringe width \[\propto \] wavelength, so the red fringe with higher wavelength is wider than the violet fringe with smaller wavelength. (ii) In higher order spectra, the dispersion is more and it causes overlapping of different colours.