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why do different colours get seprated when white light passes through a prism ? how can we recombine the components of white light after a prism has seprated them.explain

Answer: It because white light is a mixture of lights of seven colours, i.e. VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange and Red. When white light falls obliquely on a medium such as a glass prism or a sphere of plastic, it is refracted, or bent, and separated into its coloured components; this phenomenon is called dispersion. This process can thus be used to split up light into its component colours.

It is done by just mere passing light through a prism at an angle. The spectrum upon entering, refracts and the colours will surface when the light rays move out of the prism. The components are thus separated.

The theory behind dispersion lies in the varying speed of the colours in different media. Red light moves more rapidly than blue in all media. As a result, the red light is bent less than the blue light, and other colours fall in between. After passing through the medium, white light is dispersed into its components.


How to recombine the colours back into a white light:

To recombine the colours:

1. Place another prism(inverted) near the first prism and when the colours enter the second, they are recombined into one again.
2. Use a converging lens. Place the converging lens just somewhere near the prism. When the colours enter the lens, they are converged into one again the visible spectrum , light.


 

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By Applying ANother Prism Upside DownIn Series With The First

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It is because different colours have different wavelengths and the more wavelength a colour has , the less it bends.So, the seven colours bend by different amounts due to the difference in their wavelengths and so different colours get separated.

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White light is a mixture of lights of seven colors : red , orange , yellow , green , blue , indigo and violet . The dispersion of white light occurs because colours of white light travel at different speeds through the glass prism . The amount of refractrion (or bending) depends on the speed of coloured light in glass . Now , since the different colours travel at different speeds , they are refracted (or bent) by different angles on passing through the glass prism (some colours are bent less whereas others are bent more) .So , when white light consisting of seven colours falls on a glass prism , each colour in it is refracted (or deviated) by a different angle , with the result that seven colours are spread out to form a spectrum .

You can find the probable answer of your second part in this image (Link) :http://bit.ly/1horY0B .....

At first the white light is separated into seven parts by the first prism , then it is again recombined by the second prism , it recombines all the seven colours into white light.

The recombination of seven colours , produced by first prism , is due to the fact that the second prism has been placed in reversed position due to which the refraction produced by the second prism is equal and opposite to that produced by the first prism,,,.... thankx... and don't froget to give thumbs up.........

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