A glass prism is able to produce a spectrum when White light passes through it but a glass slab does-not produce any spectrum. explain why is it so?

Asked by  | 20th Feb, 2011, 04:45: PM

Expert Answer:

Dear student
In a parallel glass slab, the rays are refracted at both the parallel sides. They net refraction of the light results in only the lateral displacement of the light & net deviation of the light to be zero.
In case of a prism, due to its angular sides, there is a net deviation produced.
So in case of a prism, when a white light passes through each of the constituent wavelength of light undergoes different extent of deviation. this results in the dispersion of white light into its constituent colours.
On the other hand, the light through the parallel sides of glass slab, each contituent wavelength of white light doesnot undergo any net deviation. Hence the white light does not split into consituent spectrum. 
We hope this clarifies your query.

Answered by  | 20th Feb, 2011, 08:32: PM

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