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प्रश्न
Explain the Term: Hypermetropia
उत्तर
With age, the elasticity of the lens decreases, and the individual becomes long-sighted and is called Hypermetropia In this condition, the diameter of the eyeball from front to back is too short. The clear image falls beyond the retina and the eye sees a blurred image. Hypermetropia may be corrected by the use of a biconvex lens.
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संबंधित प्रश्न
What is the far point and near point of the human eye with normal vision?
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
Which defect of vision can be rectified:
by using a concave lens?
Name the defect of vision in which the eye-lens loses its power of accommodation due to old age.
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
What type of spectacle lens should he use to correct the defect?
Explain with the help of labelled ray-diagram, the defect of vision called hypermetropia, and hot it is corrected by a lens.
A person suffering from the eye-defect myopia (short-sightedness) can see clearly only up to a distance of 2 metres. What is the nature and power of lens required to rectify this defect?
The near-point of a person suffering from hypermetropia is at 50 cm from his eye. What is the nature and power of the lens needed to correct this defect? (Assume that the near-point of the normal eye is 25 cm).
The picture given here shows a person wearing 'half-moon' spectacles. What sort of eye-defect do do you think he has? Why are these particular spectacles useful to him?
A person is unable to see distinctly the objects closer than 1 m. Name the defect of vision he is suffering from. Draw ray diagrams to illustrate the cause of the defect and its correction by suitable lens.
List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow:
Name the parts labeled 1 to 4.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow:
Draw a labeled diagram to show how the above mentioned defect is rectified using the lens named above.
The near point of the eye of a person is 50 cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25 cm from the eye?
Give Reason:
Why do we see clearly in the central region of the retina?
Explain the Term: Cataract
Complete the following sentence with appropriate word :
An inability to focus on nearby objects due to loss of elasticity of the lens with age is called Iris.
Write scientific reason.
Nearsightedness, this defect can be corrected by using spectacles with concave lens.
Which of the following statement is correct?
Myopia may arise due to ____________.
