(a) Distinguish between diffraction and refraction.
(b) What is dispersion, and how is it related to diffraction and refraction?
(a) Diffraction is the bending of waves around obstacles or through narrow openings. Refraction is the bending of waves as they pass from one medium to another with a different density.
(b) Dispersion is the separation of different wavelengths of light by a prism or other optical device. It is related to diffraction and refraction because both of these phenomena cause the bending of waves, which can lead to dispersion. For example, when light passes through a prism, it is refracted and also diffracted, causing the different wavelengths to separate and create a spectrum.