With light falling normally on a transparent diffraction grating `10mm` wide, it was found that the
Channel: Doubtnut
Date: 2020-08-16

With light falling normally on a transparent diffraction grating `10mm` wide, it was found that the components of the yellow line of sodium `(589.0` and `589.6nm`) are resolved beginning with the fifth order of the spectrum. Evaluate: (a) the period of this grating,  (b) what must be the width of the grating with the same period for a double `lambda = 460.0nm` whose components differ by `0.13nm` to be resolved in the third order of the spectrum.