All About Light-Physics

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Precious Marie T. Torres 7 – JAENA (SPJ) LIGHT * Light is part of the electromagnetic spectrum, the spectrum is the collection of all waves, which include visible light, Microwaves, radio waves ( AM, FM, SW ), X-Rays, and Gamma Rays. * In the late 1600s, important questions were raised, asking if light is made up of particles, or is it waves .? * Sir Isaac Newton, held the theory that light was made up of tiny particles. In 1678, Dutch physicist, Christian Huygens, believed that light was made up of waves vibrating up and down perpendicular to the direction of the light travels, and therefore formulated a way of visualising wave propagation. * This became known as 'Huygens' Principle'. Huygens theory was the…show more content…
MODELS * RAY MODEL – The simplest mode of light. * WAVE MODEL – Color is naturally described in terms of wavelength. Required in order to explain the interaction of light with material objects of sizes comparable to or smaller than a wavelength of light. * PARTICLE MODEL – Required in order to explain the interaction of light with individual atoms. At the atomic level, it becomes apparent that the beam of light has a certain graininess to it. SPEED OF LIGHT The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact because the length of the metre is defined from this constant and the international standard for time. PROPAGATION OF LIGHT * Light and similar forms of radiation are made up of moving electric and magnetic forces. A simple example of motion similar to these radiation waves can be made by dropping a pebble into a pool of water. * The up-and-down motion is transverse, or at right angles, to the outward motion of the waves. This type of wave motion is called transverse-wave motion. The transverse waves spread out in expanding circles until they reach the edge of the pool. * Light radiates from its source in all directions until it is absorbed or diverted by some
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