The particle nature of light is well known and has important applications. There are two accepted
behaviours of light to explain the dual nature of light. In some cases, light acts like a particle, and in
others, it acts like a wave. The proof of the wave nature of light came with the discovery of
interference of light and diffraction. In this chapter, the wave nature of light will be studied with
emphasis on two important wave phenomena, the diffraction and interference of light.