A transparent diffraction grating of a quartz spectrograph is `25mm` wide and has `250` lines
Channel: Doubtnut
Date: 2020-08-30

A transparent diffraction grating of a quartz spectrograph is `25mm` wide and has `250` lines per millimetre. The focal length of an objective in whose focal plane a photographic plate is located is equal to `80cm`. Light falls on the grating at right angles. The spectrum under investigating includes a doublet with components of wavelength `310.154` and `310.184nm`. Determine: (a) the disatnce on the photographic plate between the components of this doublet in the spectra of the first and the second order,  (b) whether these components will be resolved in these orders of the spectrum.