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प्रश्न
Comment on the statement: ‘When any ray of white light is incident on a glass prism, it simply disperses it into its seven constituent colours.
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उत्तर
Before making any comment, the following simple experiment should be performed.

Arrangement is shown in the diagram. P1 and P2 are two glass prisms exactly similar and placed at some distance from each of the such that their refracting surfaces are parallel to each other and the base of the prism P2 is upwards and vertex downwards. S is a narrow slit through which a ray of white light is incident on the refracting face of the prism P1. It is dispersed by it into its seven constituent colours.
When this dispersed light falls on the refracting surface of the prism P2, having its base upwards so that the rays have deviated in a direction different from the first, we see on the screen only a white spot of light. It is evident that the second prism P2 recombines these colours to form white light acting as a ‘recombination prism’ while the first prism acts as a ‘dispersing prism’.
संबंधित प्रश्न
Why is the colour red used as a sign of danger?
How does the deviation produced by a triangular prism depend on the colours (or wavelengths) of light incident on it?
Which colour of white light travels fastest in glass?
If a monochromatic beam of light undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base?
What is understood by the term dispersion of light? What is its cause?
Name the radiation of a wavelength longer than 8 × 10−7 m.
Draw a neat diagram to show the arrangement you would use to project a pure spectrum of white light on a screen.
Which colour of white light travels slowest, in glass?
The wavelengths for the light of red and blue colours are nearly 7·8 × 10-7 m and 4·8 × 10-7 m respectively.
Which colour has greater speed in glass?
