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Question
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
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Solution
Our eyes are designed to focus at a great variety of distances. To focus constantly at a short distance can make the lens focusing muscles fatigued. Therefore, we do not enjoy watching a movie from a very short distance from the screen in cinema hall.
RELATED QUESTIONS
Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to gradual weakening of the ciliary muscles. What types of lenses are required by the person suffering from this defect to see the objects clearly?
Akshay, sitting in the last row in his class, could not see clearly the words write on the blackboard. When the teacher noticed it, he announced if any student sitting in the front row could volunteer to exchange his seat with Akshay. Salman immediately agreed to exchange his seat with Akshay. He could now see the words written on the blackboard clearly. The teacher thought it fit to send the message to Akshay’s parents advising them to get his eyesight checked.
In the context of the above event, answer the following questions:-
(a) Which defect of vision is Akshay suffering from? Which type of lens is used to correct this defect?
(b) State the values displayed by the teacher and Salman.
(c) In your opinion, in what way can Akshay express his gratitude towards the teacher and Salman?
Name one defect of vision (or eye) which cannot be corrected by any type of spectacle lenses.
An eye has a near point distance of 0.75 m. What sort of lens in spectacles would be needed to reduce the near point distance to 0.25 m? Also calculate the power of lens required. Is this eye long-sighted or short-sighted?
A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:
- if the person is an old man
- if the person is a young man
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Myopia and Hypermetropia.
Give Technical Term:
The path which responsible for protecting the eye from sweat.
The diagram given below represents the cross-section of the human eye:
(i) Name the parts labeled 1—12.
(ii) What is the function of the part marked ‘10’?
(iii) What would happen if part ‘5’ is damaged or cut?
Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye :
(i) Identify the defect shown in the diagram.
(ii) Give two possible reasons for the above defect.
Myopia may arise due to ____________.
Given alongside is a diagram depicting a defect of the human eye. Study the same and answer the questions that follow:
 |
- Name the defect shown in the diagram.
- Give two possible reasons for this defect.
- Name the parts labelled 1 to 4.
- Name the type of lens used to correct this eye defect.
- Draw a labelled diagram to show how the above mentioned defect is rectified using the lens named above.
