- That portion of electromagnetic radiation (between 390 and 770 nm) to which the retina is sensitive (wavelength range of 380–780 nm). SEE ALSO: lamp. [A.S. leoht]- invisible l. historic term for x-rays.- polarized l. l. in which, as a result of reflection or transmission through certain media, the vibrations are all in one plane, transverse to the ray, instead of in all planes.- reflected l. l. directed backward from a mirror.- refracted l. bent rays of l. changed in passage from one transparent medium to another of unequal density. SEE ALSO: refraction.- transmitted l. l. passed through a transparent medium.
* * *light 'līt n1 a) the sensation aroused by stimulation of the visual receptorsb) an electromagnetic radiation in the wavelength range including infrared, visible, ultraviolet, and X-rays and traveling in a vacuum with a speed of about 186,281 miles (300,000 kilometers) per second specif the part of this range that is visible to the human eye2) a source of lightlight or lite adj made with a lower calorie content or with less of some ingredient (as salt, fat, or alcohol) than usual <\light salad dressing>
* * *(līt) the electromagnetic radiation having a velocity of about 3 Ð§ 1010 cm (186,284 miles) per second, and the vibrations in space being at right angles to the direction of transmission. Frequently construed as limited to the range of wavelength between 390 and 770 nanometers, which provides the stimulus for the subjective sensation of sight, but sometimes considered as including part of the ultraviolet and infrared ranges as well.
Medical dictionary. 2011.