Question

A miniature spectrometer used for chemical analysis has a diffraction grating with 800 slits/mm set 25.0 mm in front of the detector "screen." The detector can barely distinguish two bright lines that are 30 μm apart in the first-order spectrum. A miniature spectrometer used for chemical analysis has a diffraction grating with 800 slits/mm set 25.0 mm in front of the detector "screen." The detector can barely distinguish two bright lines that are 30 μm apart in the first-order spectrum.

Answer 1

Resolvance of Grating is
and

   R =mN , m is order of diffraction , N is number of slits illuminated.

one of the wavelengths that clearly distinguish the wavelength is 550 nm,

   substituting the data

equatig

   given first order 1, number of slits 800, ==> = 550/1.800 = 0.625 nm

the wave length difference between them is is 0.625 nm