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प्रश्न
What is a rainbow? What are the two conditions necessary for the formation of a rainbow in the sky?
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उत्तर
A rainbow is a natural spectrum of seven colours formed in the sky when the water droplets in the atmosphere cause the dispersion of sunlight. The two conditions necessary for the formation of a rainbow are as follows.
1. The sun should be shining.
2. It should be raining.
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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
Define the term dispersion of white light.
Draw a ray diagram to show the dispersion of white light.
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
The splitting of white light into its constituent colours is called .............
The seven colours in the spectrum of sunlight in order, are represented as :
Which is optically denser: water or air? Give reason
Out of air and glass, which is optically rarer? Give reason.
What conclusion do you draw about the nature of white light in part (b)?
When a white light ray falls on a prism, the ray at its first surface suffers ______.
The frequency range of visible light is from 3.75 × 1014 Hz to 7.5 × 1014 Hz. Calculate its wavelength range. Take speed of light = 3 × 108 m/s.
In an experiment to trace the path of a ray of light through a triangular glass prism, a student would observe that the emergent ray
(a) is parallel to the incident ray.
(b) is along the same direction of incident ray.
(c) gets deviated and bends towards the thinner part of the prism.
(d) gets deviated and bends towards the thicker part (base) of the prism.
Make the correct choice for each of the following:
Which one of the following Fig correctly shows the path of the ray through the glass block?
The wavelength range of white light is ______.
A wave has wavelength 50Å of State its one use.
In the figure, a beam of light consisting of three colours blue, red, and yellow is incident on a prism and on a rectangular glass block respectively. Complete the diagram by drawings of the refracted and emergent rays.
When white light enters a glass prism from the air, the angle of deviation is least for ____________.
Observe the given diagram and answer the questions:
- Name the process shown in the figure.
- Name the colour that deviates the most.
- Name the colour that deviates the least.
- Name any one phenomenon in nature which is based on the above process.
- Define ‘spectrum’.
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.
Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?
