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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
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.
Fill in the blank with suitable word:
When a ray of light enters a prism, it bends ................ the normal ; as it leaves the prism, it bends ................. the normal.
In the figure given alongside, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum YX on the screen.
Why do different colours of white light bend through different angles with respect to the incident beam of light?
Draw a diagram to show the refraction of light through a glass prism. On this diagram, mark
(i) incident ray
(ii) emergent ray, and
(iii) angle of deviation.
Out of the following, the colour of light having the maximum wavelength is:
(a) violet
(b) indigo
(c) green
(d) orange
The diagram below shows the path taken by a narrow beam of yellow monochromatic light passing through an equiangular glass prism. If the yellow light is replaced by a narrow beam of white light incident at the same angle, draw another diagram to show the passage of white light through the prism and label it to show the effect of prism on the white light.
What do you understand by the term spectrum?
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.
Complete the ray diagram given below to show the nature of light produced on the screen.
The completed ray diagram is as shown below:
The wavelengths of violet and red light are 4000 Å and 8000 Å respectively. Which of the two has the higher frequency?
Draw a labelled diagram: Dispersion of light through a prism.
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
How can the presence of ultraviolet radiation be detected?
State two uses of ultraviolet radiation.
Write the range of wavelength of the visible spectrum.
Suggest one way, in each case, by which we can detect the presence of Infrared radiations.
The process of separation of light into its component colours while passing through a medium is called _______.
Observe the given figure and write appropriate phenomenon of light in the box.
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.
