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#Dispersio of light how to#
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The use of symmetric doublets like the arthroscopic doublet greatly reduces spherical aberration. For multiple lenses, spherical aberrations can be canceled by overcorrecting some elements. But when it passes through a rectangular glass slab no color is seen.ĭispersive power can be defined as the relative change in the focal length of a lens$\frac$įor lenses made with spherical surfaces, rays which are parallel to the optic axis but at different distances from the optic axis fail to converge to the same point, For a single lens, spherical aberration can be minimized by bending the lens into its best form. Which figure shows the correct light colour (s) after passing through prism Reveal Answer 2. Three light rays: one red, one blue and one green fall on a glass prism as shown in the figure. Hence, when a ray of white light is passed through a glass prism, it is dispersed into different colors. Physics Revision Questions for Dispersion of Light 1. But at the second face of the prism, the dispersion is opposite to that of the first face and equal in magnitude, so they cancel each other and the light emerging from second face of slab is white. When white light enters into a rectangular glass slab, it is dispersed at the first face by first prism.
But when it is passed through a rectangular glass slab no color is seen as it behaves as combination of two prism of same refractive index attached in opposite manner to each other. When a ray of light is passed through a glass prism it get dispersed because the different colors of light are deviated in different amount. Thus violet light will be deviated more and lies outwards bottom where as red light deviated less towards top of the spectrum. The deviation produced by prism is δ = (μ -1) A, where μ is refractive index of material of the prism and A is angle having more wavelengths ids deviated least than the violet light. The dispersion occurs due to refraction because the white light has to travel in the glass medium to disperse whereas the mirror is an opaque object. The cause of dispersion of light is due to the variation of the refractive index of the medium with color of light.Ī substance in which waves of different frequencies travel at different speed is known as dispersive medium
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