Terminologies Related to Spherical Lens
- Pole (p): It is the middle point of the spherical lens or mirror.
- Centre of curvature (C): It is the center of the sphere from which the mirror is formed.
- Principal axis: It is the lines passing through the pole and the center of curvature of the lens.
- Principal focus (F): It is the point at which a narrow beam of light converges or diverges.
- Focal length (f): It is the distance between the focus and the poles of the mirror.
Image Formation by Lenses
In optics, a ray is a geometrical representation of the light that is idealized by choosing a curve that is perpendicular to the wave fronts of actual light and points in the energy flow direction. Rays are used to represent the propagation of light through an optical system by separating the real light field into discrete rays that can be computationally carried through the system using ray-tracing techniques. This makes it possible to investigate or simulate even the most complex optical systems mathematically. Ray tracing is based on approximate solutions to Maxwell’s equations that hold true as long as light waves flow through and around objects with dimensions significantly greater than the wavelength of the light. Diffraction, for example, necessitates the study of wave optics, which is not addressed by ray or geometrical optics. Adding phase to the ray model can be used to describe wave phenomena such as interference in some instances.