Question

A monochromator for a new instrument has a reciprocal linear dispersion of 1.2 nm/mm and it is to be used to separate the magnesium lines at 279.1 nm and at 279.8 nm. (a) Calculate the effective bandwidth (Δλeff). (3p) (b) Calculate what slit width would be required to resolve the two lines above. (need correct formula and calculation)

Answer 1

The reciprocal linear dispersion represents the number of wavelength intervals
(e.g., nm) contained in each interval of distance (e.g., mm) along the focal plane.

Effective bandwidth is the width between the two spectral lines.