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Commentary_" ...the division of light energy into two categories: 'Atapa and Uddyota, is based on scientific considerations: 'Atapa is the sunlight or light of a fire, or electric lamp, etc., and uddyota is the moonlight, the light emitted by the jewels or the phosphorescent light of a fire-fly (Sarv"artha Siddhi, 51 2-4). The former predominates in heat rays and the latter in
light rays. The efficiency of modern electric lamp is only 7-10 .% and that of arc-lamp 15% (in the tube light lamps, the
efficiency has reached about 60%). In other words only 7 or 15 percent of energy is converted into light and the rest appears in the form of heat. Thus the light given by these sources has a much greater proportion of heat than light, and hence the name 'Atapa. The same is the case with the sun where only 35 percent of the radiation appears in the form of light. The efficiency of the tiny lamp in the body, of the glowworm is 99 percent of light rays and 1 percent of heat rays; hence
the most proper name given to it is Uddyota." 52. J.S. Zaveri and Muni Mahendra Kumar, Microcosmology ... , p. 15 "Electromagnetic Radiation--Light
“Much earlier, there were two theories about light : One which Newton favoured was that it was composed of particles called, corpuscles, the other was that it was made of waves. A proper theory of the propagation of light did not come until 1865, when Maxwell succeeded in unifying the forces of electricity and magnetism. Maxwell's equations predicted that electromagnetic waves travel at a fixed speed. Thus, light is a rapidly alternating electromagnetic field travelling through space in the form of waves at a fixed speed. In due course, it was established that radio-waves, light and Xray are all waves forming the electromagnetic spectrum, a tiny fraction of which the visible spectrum is visible in the form of light. This remained the accepted and proven theory of light upto 1905. Einstein's theory of light was that it is composed of tiny particles called photons. A beam of light is analogous to a stream of bullets. To prove his theory, Einstein referred to a phenomenon called the photo-electric effect, in which when light impinges on a metal surface, it sends electrons flying off. If a photon hits an electron, it knocks it away just as one billiard ball hitting another one knocks it away.
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