Light falls normally on a transparent diffraction grating of width `l = 6.5cm` with `200` lines p
Channel: Doubtnut
Date: 2020-08-16

Light falls normally on a transparent diffraction grating of width `l = 6.5cm` with `200` lines per millimetre. The spectrum under inverstigation includes a spectral line with `lambda = 670.8 nm` consisting of two components differing by `delta lambda = 0.015nm`. Find:   (a) in what order of the spectrum these components will be resolved, (b) the least difference of wavelength that can be resolved by this grating in a wavelength region `lambda ~~ 670nm`.