Lights and optics Essay Example | Topics and Well Written Essays - 1250 words

Lights and optics - Essay Example This theory formulated a new way of visualization of the propagation of waves called as â€Å"Huygens† Principle. Newton’s Particle Theory Newton’s particle theory of light is also known as the Corpuscular Theory of Light. Newton published Opticks in the year 1704, 17 years after the publishing of Principia (â€Å"Newton’s Particle Theory†). In Opticks, Newton said that light is made up of little masses, which implies that a horizontal light beam near the earth forms a parabola, thus undergoing a projectile motion. The immensity of the speed of particles of which light is composed is the reason why it is observed as a straight line in spite of its projectile motion. The speed of the travelling of light is 300m per microsecond, during which â€Å"it should fall a distance y = 1/2gt2 = 5*10-12 m, much too small to be seen† (â€Å"Newton’s Particle Theory†). The particle model easily explained a range of the then known properties o f light. For instance, it explained why the angle of incidence and the angle of reflection of light were equal as light reflected from a smooth surface. This also explained the phenomenon of bouncing back of a frictionless elastic ball from a smooth surface. Refraction is a major property of the particle theory of light. ... on of wave was in parallel direction to the wave travel’s direction rather than perpendicular to the wave travel direction as happens in the case of light. Although the Corpuscular Theory of Light could explain the phenomena of primary and secondary rainbows, yet it failed to lay down an appropriate explanation of the supernumerary bow, the iridescent cloud, or the corona. The Wave Theory of Light Huygens proposed a successful theory of the wave motion of light in three dimensions. In this theory, Huygens said that light wave emerges from surfaces like onion’s layers. Light waves are spherical in uniform mediums or vacuum. As the wave surfaces propagate with the speed of light, they spread out. According to Huygens, gravity does not affect the light waves. Huygens disagreed with Newton saying that the speed of light reduces as it travels from air to water whereas it increases when it moves from water to air. Later, Huygens was found to be correct. Each color exhibited b y the wave as it spreads out from the source carries a different wavelength. Supernumerary bows could be explained with the assumption of light as a wave. Huygens wave theory elaborates the reason why light spreads out of a slit or a pin hole instead of making a straight line. Although the theory of Newton preceded Huygens’s, yet early experiments were explained better by the theory of Huygens. Huygens’s principle can be used to assess the location of a certain wavefront in the future if its present location is known. The Dual Nature of Light In the year 1803, Thomas Young shone light through a screen to study the interference of light waves. The screen had two equally separated slits. As light passed through them, it emerged spreading out following the Huygen’s principle. The two wave fronts