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प्रश्न
State the cause of dispersion of white light passing through a glass prism. How did Newton show that white light of sun contains seven colours using two identical glass prisms. Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the focus of the first prism.
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उत्तर
Different colours of light bend through different angles with respect to the incident ray as they pass through a prism. The red light bends the least, while the violet bends the most. Thus, the rays of each colour emerge along different paths and thus become distinct. This is the cause of dispersion of white light passing through a glass prism.
Isaac Newton used two glass prims, with one prism in inverted position to show that white light of the Sun contains seven colours. The set-up has been shown below:-
When white light of the Sun passes through the first prism, it gets dispersed into seven colours. When all the seven colours of the spectrum were passed through the second prism, Newton found a beam of white light emerging from the other side of the second prism. This observation gave Newton the idea that the sunlight is made up of seven colours.
संबंधित प्रश्न
A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.
Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.
(i) Write the name and cause of the phenomenon observed.
(ii) Where else in nature is this phenomenon observed?
(iii) Based on this observation, state the conclusion which can be drawn about the constituents of white light.
Name the process which is involved in the formation of a rainbow.
The seven colours in the spectrum of sunlight in order, are represented as :
Which is optically denser: water or air? Give reason
What do you understand by the term spectrum? Name the various colours present in the spectrum of sunlight.
In which of the following four diagrams is the correct path of a ray of light passing through a glass prism shown ?
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?
Which characteristic property of light is responsible for the blue colour of the sky?
Suggest one way, in each case, by which we can detect the presence of Infrared radiations.
When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.
Instead of sunlight, a green-coloured ray is passed through a glass prism. What will be the colour of the emergent ray?
