A student is the class has difficulties in seeing the letters written on the whiteboard when he sits on the last bench but he sees them clearly when he sits on the first bench. Based on this, answer the following questions:
- What type of defect of vision does the student have?
- Draw a ray diagram showing this type of defect of vision of the student.
- Write any two reasons for this defect.
- Explain, with a ray diagram, the role of the lens used to correct this defect.
Arpit Sundas
·
1 year ago
Solution
1.Ans:
According to the questions, the student finds it hard to see letters from a distance but is able to see them from short distance.
Hence the student has short-sightedness or myopia.
3.Ans:
Two reasons for this defect are:
- Shortening of focal length of eye
- The eye is too long or oval-shaped rather than round.
2.Ans:
Diagram:
4.Ans:
The above diagram shows the role of of the lens used to correct this defect.
Concave lens of suitable focal length should be used to correct this defect. The lenses diverge the rays passing from distant objects to retina. Hence, clear image of distant objects is formed after the use of concave lens.