Pincushiondistortion

When we look at a leaf we know that it is green because light bounces off the leaf to our eyes to tell us that it is green. But what is light? Which are the sources of light from which light originated? Light is electromagnetic radiation. A particular frequency of this radiation (around 390-700 nm) is visible to the human eye. Everything that we see around us is because of light. Light is a form of energy and like all energies, it is produced from a source. In Physics, these are called light sources.

The universe is filled with objects that emit light. Some light from these sources reaches the earth. The following things in nature have the ability to emit light:

What is barrel distortioncorrection

When certain objects are heated to a high temperature, they begin to emit light. Both infrared and visible light is produced in the process.

Light can be produced by accelerating charges in a luminescent material. One common way of doing it is by passing current through the material.

What is barrel distortionin photography

…be present in a lens: barrel distortion, in which magnification decreases with distance from the axis, and pincushion distortion, in which magnification increases with distance from the axis.

Apart from natural sources, light can be produced artificially too. The different light sources produced artificially can be put under three broad categories-