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प्रश्न
What are the seven colours seen in a rainbow?
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उत्तर
The seven colours seen in a rainbow are red, orange, yellow, green, blue, indigo and violet.
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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
Describe an activity to show that colours of white light splitted by a glass prism can be recombined to get white light by another identical glass prism. Also draw ray diagram to show the recombination of the spectrum of white light.
A student is observing a diagram showing the path of a ray of light passing through a glass prism. He would find that for all angles of incidence the ray of light bends:
In the following diagram the correctly marked angles are :

(a) ∠A and ∠e
(b) ∠i, ∠A and ∠D
(c) ∠A ∠r and ∠e
(b) ∠A ∠r and ∠D
In the formation of spectrum of white light by a prism:
- which colour is deviated least?
- which colour is deviated most?
When a beam of white light is passed through a prism, it splits to form lights of seven colours. Is it possible to recombine the lights of seven colours to obtain the white light again? Explain your answer.
What is a rainbow?
Which of the following colour of white light is least deviated by the prism?
(a) green
(b) violet
(c) indigo
(d) yellow
The splitting up of white light into seven colours on passing through a glass prism is called ______.
Why do you not see a spectrum of colours when light passes through a flat pane of glass?
The seven colours in the spectrum of sunlight in order, are represented as :
Define the term dispersion of light.
What do you understand by the term spectrum?
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?
Draw a labeled ray diagram to illustrate the dispersion of a narrow beam of white light when it passes through a glass prism.
An object is placed in front of a converging lens and in front of a diverging lens as in fig.

(a)Complete the ray diagram to obtain an image.
(b)Compare the nature of image formed by both the lenses in the above case.
A wave has wavelength 50Å of State the speed in vacuum.
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
The angle of deviation through a prism is minimum when

- Incident rays and emergent rays are symmetric to the prism.
- The refracted ray inside the prism becomes parallel to its base.
- The angle of incidence is equal to that of the angle of emergence.
- When the angle of emergence has doubled the angle of incidence.
Choose the correct answer from the options given below:
