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प्रश्न
Why do we see a rainbow in the sky only after rainfall?
We see a rainbow in the sky only after the rainfall.” Why?
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उत्तर
Raindrops present in the atmosphere after rainfall serve as a prism and refract, disperse, and internally reflect the incident sunlight, followed by final refraction. The whole sequence of dispersion and internal reflection leads to the formation of the rainbow after rainfall in the sky.
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संबंधित प्रश्न
Study the following diagrams in which the path of a ray of light passing through a glass prism as traced by four students P, Q, R and S is shown:
The student who has traced the path correctly is
(A) P
(B) Q
(C) R
(D) S
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
How could you show that the colours of the spectrum combine to give white light?
What are the seven colours seen in a rainbow?
The colour of white light which is deviated the maximum on passing through the glass prism is:
(a) blue
(b) indigo
(c) red
(d) orange
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 coloured light having the maximum speed in glass prism is:
(a) blue
(b) green
(c) violet
(d) yellow
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.
While performing the experiment to trace the path of a ray of light passing through a glass prism, four students marked the incident ray and the emergent ray in their diagrams in the manner shown below. 
(A) I
(B) II
(C) III
(D) IV
When we place a glass prism in the path of a narrow beam of white light a spectrum is obtained. What happens when a second identical prism is placed in an inverted position with respect to the first prism? Draw a labelled ray diagram to illustrate it.
A student has to trace the path of a ray of light through a glass prism. List four precautions he should observe for better results.
Which characteristic property of light is responsible for the blue colour of the sky?
Observe the given figure and answer the following questions.
- Which colour light rays bend most?
- Which colour light rays bend least.
- What is the wavelength of violet light rays?
The splitting of white light into its component colours is called ____________.
What is Newton’s disc?
A prism of refractive index `sqrt2` and refracting angle A produces minimum deviation δm of a ray on one face at an angle of incidence 45°, The values of A and δm are, respectively ______.
State True or False:
"Wavelength of red light is close to 700 nm.”
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?
