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प्रश्न
Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.
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उत्तर
The figure shows a myopic eye, in which the eye lens is unable to focus the light rays coming from distant object onto the retina. In this defect, the image of distant object is formed before the retina i.e., the light rays converge before they reach the retina. Hence, to correct this defect a diverging lens (concave lens) of proper focal length is used, so that, the rays reach the retina after refraction and the person can see the image clearly.
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संबंधित प्रश्न
What is the other name for
myopia
What is the other name for
hypermetropia
What is the scientific name of
short-sightedness
What is the scientific name of
long-sightedness?
Name the defect of vision which makes the eye-lens cloudy resulting in blurred vision.
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
From which defect of the eye is he suffering?
A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
Name the type of defect he is suffering from.
A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
How can this defect by corrected?
Name the defect of vision which can be corrected by a diverging lens. Show clearly by a ray diagram how the lens corrects the defect.
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?
A person having short-sight cannot see objects clearly beyond a distance of 1.5 m. What would be the nature and power of the corrective lens to restore proper vision?
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?
Though a woman can see the distant object clearly, she cannot see the nearby objects clearly. She is suffering from the defect of vision called:
(a) long-sight
(b) short-sight
(c) hind-sight
(d) mid-sight
The defect of vision in which the eye-lens of a person gets progressively cloudy resulting in blurred vision is called:
(a) myopia
(b) presbyopia
(c) colourblindness
(d) cataract
Name the following:
The photosensitive pigment present in the rods of the retina.
Name an old age eye defect. What happens in it?
What is meant by optical illusion? Give one example.
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
Enumerate the common defects of vision, their causes and the possible methods of correcting them.
Given below is a diagram depicting a defect of the human eye. Study the same and answer the question that follow:
Name the defect shown in the diagram.
Have a look at the posture of this girl who is reading a book and answer the questions which follow:
Name the problem she is facing.
A person cannot read newspaper placed nearer than 50 cm from his eyes. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length.
What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
Name the following:
The photosensitive pigment present in the rod cells of the retina.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What are the two conditions shown in sections A and B of the eye as applicable to her?
Give Reason:
When you enter into a dark room from bright because of sunlight, you can not see things for a few seconds.
Give Technical Term:
The path which responsible for protecting the eye from sweat.
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.
Given below is a diagrammatic representation of a defect of the human eye:
(i) Identify the defect.
(ii) Mention two reasons for the above defect.
(iii) State how the defect can be rectified.
(iv) Name the part of the eye responsible for maintaining the shape of the eyeball.
What are the causes of ‘Myopia’?
Myopia and hypermetropia can be corrected by:
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.
