When an incident ray of light enters in a medium 'X' from medium 'Y', it bends away from the normal. Comment about the following:
(a) Speed of light in medium 'X' with respect to the speed of light in medium of 'Y'.
(b) Optical density of medium 'X' with respect to the optical density medium 'Y'.
Give reason for your answer in each case.
When an incident ray of light enters in a medium 'X' from medium 'Y', it bends away from the normal. Comment about the following:
(a) Speed of light in medium 'X' with respect to the speed of light in medium of 'Y'.
(b) Optical density of medium 'X' with respect to the optical density medium 'Y'.
Give reason for your answer in each case.
Official answer
(a) Speed of light in medium 'X' is more than the speed of light in medium 'Y'.
(b) Optical density of medium 'X' is less than the optical density of medium 'Y'.
Reason: When an incident ray of light enters in a medium 'X' from medium 'Y', it bends away from the normal. This means that the light is moving from a denser medium to a rarer medium. Hence, the speed of light in medium 'X' is more than the speed of light in medium 'Y'. Also, the optical density of medium 'X' is less than the optical density of medium 'Y'.
Marking scheme
- 1.2 marks
Hint
Recall the definition of refraction of light and how it relates to the speed of light and optical density of a medium.
Quick oral answer
When light enters a medium 'X' from medium 'Y' and bends away from the normal, it means that the light is moving from a denser medium to a rarer medium. Therefore, the speed of light in medium 'X' is more than the speed of light in medium 'Y'. Also, the optical density of medium 'X' is less than the optical density of medium 'Y'.
Common mistakes
- 1.confusing the terms 'speed of light' and 'optical density'
- 2.not providing a reason for the answer
Analysis and explanation
The question requires the student to understand the concept of refraction of light and how it relates to the speed of light and optical density of a medium. The student needs to analyze the situation and provide a reason for their answer.
Interesting facts
The speed of light in a vacuum is approximately 299,792,458 meters per second.
The optical density of a medium is a measure of how much it bends light.
Question details
Q33 of 39 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2026
- Section
- Section C
- Marks
- 2
- Type
- Short Answer
- Chapter
- Light — Reflection and Refraction
- Topic
- Refraction of Light
- Bloom's level
- Comprehension
- Syllabus topic
- Refraction of Light
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2026?
This question carries 2 marks in the CBSE Class 10 Science 2026 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Light — Reflection and Refraction" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Refraction of Light" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2026 paper?
This is a Short Answer question from Section C in the CBSE Class 10 Science 2026 paper.