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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.
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उत्तर
(i) Dispersion of light
Cause: The dispersion of white light occurs because colors of white light travel at different speeds through glass prism. Different colours undergo different deviations on passing through prism.
(ii) Rainbow is the example of dispersion of light observed in nature.
It is caused due to dispersion of sunlight by water droplets in the atmosphere. It always forms in the direction opposite to the sun.
(iii) White light is a mixture of seven colours. The sequence of colours given by the prism is Violet, Indigo, Blue, Green, Yellow, Orange and Red. VIBGYOR is the acronym for this sequence. The red light bends the least and violet light bends the most.
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संबंधित प्रश्न
Study the following figure in which a student has marked the angle of incidence (∠i), angle of refraction (∠r), angle of emergence (∠e), angle of prism (∠A) and the angle of deviation (∠D). The correctly marked angles are
(a) ∠A and ∠i
(b) ∠A, ∠i and ∠r
(c) ∠A, ∠i, ∠e and ∠D
(d) ∠A, ∠i, ∠r and ∠D
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.
As light rays pass from air into a glass prism, are they refracted towards or away from the normal?
What acts as tiny prisms in the formation of a rainbow?
The splitting up of white light into seven colours on passing through a glass prism is called:
(a) refraction
(b) deflection
(c) dispersion
(d) scattering
A ray of white light is passed through a glass prism and a spectrum is obtained on a screen.
- Name the seven colours of the spectrum in order.
- Do the colours have the same width in the spectrum?
- Which of the colour of the spectrum of white light deviates (i) the most, (ii) the least?
The phenomenon of splitting of light into its component colours is ___________ .
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
Write the range of wavelength of the visible spectrum.
In dispersion, the color of light that will bend more is ______.
