What critical function does the entrance slit serve in a spectrometer?

Answer

It limits the beam entering the system and ensures the light is highly collimated.

The entrance slit limits the light beam defining the initial spatial resolution and ensures the radiation entering the dispersing element is highly collimated, meaning its rays are nearly parallel.

What critical function does the entrance slit serve in a spectrometer?
spectrometerlightinstrumentpurposeanalysis