- Optics is the branch of physics that studies the behaviour and properties of light, including visible, ultraviolet, and infrared light.
- Visible, ultraviolet, and infrared light, along with X-rays, microwaves, and radio waves, are all examples of electromagnetic radiation.
- Many optical phenomena can be explained using the classical electromagnetic theory that describes light in terms of waves.
- Geometric optics describes light as travelling in straight lines and changing direction when passing through or reflecting from surfaces. These phenomena can be analysed using ray diagrams.
- Ray diagrams are useful when explaining the workings of everyday objects such as mirrors, lenses, telescopes, microscopes, lasers, and fibre optic devices.
- Some optical effects such as diffraction and interference can be explained in terms of the particle-like properties of photons and with reference to the field of quantum mechanics.
- About photons: