In physical optics, light is considered to engender as a wave. This model predicts wonders, for example, obstruction and diffraction, which are not clarified by geometric optics. The speed of light waves in air is roughly 3.0×108 m/s (precisely 299,792,458 m/s in vacuum). The wavelength of obvious light waves differs in the vicinity of 400 and 700 nm, however the expression "light" is additionally regularly connected to infrared (0.7– 300 μm) and bright radiation (10– 400 nm).
1. Superposition and interference
2. Diffraction and optical resolution
3. Dispersion and scattering