Question

If the light is incident on a diffraction grating, then the zero order maximum will be given as,
A. spectrum of colours
B. white
C. one of the component colours
D. absent

Answer 1

A very interesting phenomenon occurs when you pass the light through a huge number of evenly spaced parallel slits which are known as a diffraction grating. An interference pattern is developed which will be very identical to the one created by a double slit. A diffraction grating can be produced by scratching glass with any sharp instruments in a number of precisely positioned parallel lines which are having untouched regions found as slits. This will help you in answering the question.

Complete answer:
Diffraction gratings are generally helpful for spectroscopic dispersion and also in analysis of light. They are having a specific use that they will form a sharper pattern than made by the double slits. Therefore their bright regions will be narrower and brighter and also their dark regions will be darker. Light which is passed through this will be diffracted in a pattern identical to a double slit, with bright regions at different angles. When the pattern produced by the white light incident on a grating is analysed, we can see that the central maximum will be white, and the higher-order maxima disperse the white light into a rainbow of colours.

Therefore the answer for the question will be given as option B.

Note:
Natural diffraction gratings are produced in the feathers of some of the birds also. Small finger-like structures in regular patterns will be acting like reflection gratings which will create a constructive interference that will provide the feathers colours not solely because of their pigmentation. This is referred to as iridescence.