A different grating has numerous tiny slits, equally spaced. It separates white light into its component colors just as a double slit would. When a sinq = n l, light of wavelength l will be reinforced at an angle of q. Since different colors have different wavelengths, different colors will be reinforced at different angles, and a prism-like spectrum can be produced. A diffraction grating is the tool of choice for separating the colors in incident light.
Lecture on Diffraction Gratings
