- Optics is the branch of physics that describes the behaviour of visible, ultraviolet, and infrared light.
- Visible, ultraviolet, and infrared light along with X-rays, microwaves, and radio waves are all forms of electromagnetic radiation.
- Many optical phenomena can be accounted for using the classical electromagnetic description of light as propagating in the form of waves.
- Geometric optics treats light as collections of rays that travel in straight lines but bend when they pass through or reflect from surfaces.These behaviours are often mapped out using ray diagrams.
- Ray diagrams have practical application when describing how everyday objects work, including mirrors, lenses, telescopes, microscopes, lasers, and fibre optic devices.
- Some optical effects such as diffraction and interference must be explained in terms of the particle-like properties (photons) and with reference to the field of quantum mechanics and terms such as wave-particle duality.