Question: A diffraction grating has 3107 lines/cm. Light that contains all wavelengths between 420 and 656 nm shines on the grating.
Part A: Calculate the width of the dark area between the first and second order spectra on a screen 4.5 m away.
I need help to find the width of the dark area between the first and second order spectra on a screen 4.5 m away.