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| Scattering Due to Polarisation |
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When a light wave falls on a transparent solid, it causes the electrons in the solid to oscillate periodically in response to  of the incident waves. Since these oscillating charges act coherently or cooperatively there is a lack of scattering of light. But in liquids or gases, due to a larger separation between the oscillating charges, the scattering of light is more prominent. This light, which is scattered, can be wholly or partly polarized. |
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| When a beam of white light is passed through a medium containing particles of size nearly equal to the wavelength of light, the beam gets scattered. This scattered light is seen in a direction perpendicular to that of incidence and is found to be plane polarized. |
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| As light is transverse in character, all directions of vibrations of electric vector in the unpolarised light are confined to the XY plane. While looking along the X axis, vibrations of electric vector parallel to Y axis are seen and similarly along y axis. Hence light scattered in a direction perpendicular to the incident light is always plane polarized. |
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| If atmosphere was not present, the sky would appear black except in the direction of sun, as observed by astronauts orbiting above the atmosphere. This is because there is no string due to absence of molecules. |
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| The blue colour of the sky is due to reason that this colour is more effectively scattered than red light. |
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| When light is allowed to fall on bound electrons, it sets up forced oscillations at frequency of the incident light. Since the frequency of blue light in closer to the natural resonant frequency of the bound electrons, we expect blue light to effectively cause electrons to oscillate and so scatter effectively. |
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| Horizontal arrow shows calcium lines that are displayed from their position taken by source at rest in the lab. |
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| Common liquid crystal display uses polarized light to form letters and numbers. These liquid crystals are materials with stretched molecules like polarizing sheets. |
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