(a) A narrow beam XY 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 PQ. Name the phenomenon observed and state its cause. OR (b) It is observed that the power of an eye to see nearby objects as well as far off objects diminishes with age. (i) Give reason for the above statement. (ii) Name the defect that is likely to arise in the eyes in such a condition. (iii) Draw a labelled ray diagram to show the type of corrective lens used for restoring the vision of such an eye.
(a) A narrow beam XY 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 PQ. Name the phenomenon observed and state its cause. OR (b) It is observed that the power of an eye to see nearby objects as well as far off objects diminishes with age. (i) Give reason for the above statement. (ii) Name the defect that is likely to arise in the eyes in such a condition. (iii) Draw a labelled ray diagram to show the type of corrective lens used for restoring the vision of such an eye.
Official answer
The path of the emergent beam as observed on the screen PQ is shown in the diagram. The phenomenon observed is dispersion of light. The cause of this phenomenon is the different speeds of different colours of light in the glass prism. The angle of deviation for each colour is different, resulting in the separation of colours.
Marking scheme
- 1.Dispersion of light
- 2.Different speeds of different colours of light in the glass prism
Hint
The dispersion of light occurs due to the different speeds of different colours of light in the glass prism.
Quick oral answer
The dispersion of light occurs due to the different speeds of different colours of light in the glass prism. The angle of deviation for each colour is different, resulting in the separation of colours. This phenomenon is known as dispersion of light.
Common mistakes
- 1.Confusing dispersion with refraction
- 2.Not understanding the cause of dispersion
Analysis and explanation
The dispersion of light occurs due to the different speeds of different colours of light in the glass prism. The angle of deviation for each colour is different, resulting in the separation of colours. This phenomenon is known as dispersion of light.
Interesting facts
Dispersion of light is responsible for the formation of rainbows
Dispersion of light is used in spectroscopy to analyze the composition of materials
Question details
Q25 of 39 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2023
- Section
- Section B
- Marks
- 2
- Type
- Very Short Answer
- Chapter
- The Human Eye and the Colourful World
- Topic
- Refraction of Light through a Prism
- Bloom's level
- Comprehension
- Syllabus topic
- Refraction of Light through a Prism
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2023?
This question carries 2 marks in the CBSE Class 10 Science 2023 examination.
Which chapter does this question come from in Science?
This question is from the chapter "The Human Eye and the Colourful World" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Refraction of Light through a Prism" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2023 paper?
This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2023 paper.