Computer-Aided Instruction Index Vision Light Light sources emit light. For instance, an excited, energetic electron can give up a quantum of energy in the form of a photon of light.
Surfaces reflect light.
At wavelengths shorter than 400nm one gets the invisible ultraviolet lights, while at wavelengths longer than 700nm one encounters the invisible infrared lights. Has lots of nerve endings that send a potent message when the cornea is touched or scratched. Lens Crystalline yet deformable. The lens gets yellower as one ages. The lens can develop opacities called cataracts, which can necessitate removal of the lens.