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प्रश्न
State two uses of ultraviolet radiation.
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उत्तर
(i) In producing vitamin D in plants.
(ii) For sterilizing purposes.
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संबंधित प्रश्न
After tracing the path of a ray of light through a glass prism a student marked the angle of incidence (∠i), angle of refraction (∠r) angle of emergence (∠e) and the angle of deviation (∠D) as shown in the diagram. The correctly marked angles are :
(A) ∠i and ∠r
(B) ∠i and ∠e
(C) ∠i, ∠e and ∠D
(D) ∠i, ∠r and ∠e
State the cause of dispersion of white light
- A ray of white light breaks up into its components while passing through a glass prism. Draw a ray diagram to show the path of rays.
- Mark the least deviated colour in your diagram.
- Why do different coloured rays deviate differently in a prism?
In the formation of spectrum of white light by a prism:
- which colour is deviated least?
- which colour is deviated most?
In which of the following four diagrams is the correct path of a ray of light passing through a glass prism shown ?
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.
Refer to fig
(i) Name the lens L.
(ii) What are the points O, O' called?
(iii) Complete the diagram to form the image of the object AB.
(iv) Write three characteristics of the image.
dispersive power of crown glass? Given that µv = 1.5230, µr = 1.5145
A ray of light is incident at 45° on an equilateral prism in the diagram below.
- Name the phenomenon exhibited by the ray of light when it enters and emerges out of the prism.
- State the cause of the above phenomenon mentioned by you.
Make a rainbow
Try to make your own rainbow. You can try this project in the morning or in the evening. Stand with your back towards the Sun. Take a hosepipe or a water pipe used in the garden. Make a fine spray in front of you. You can see different colours of rainbow in the spray.
