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प्रश्न
In what two whys is a yellow spot different from the blind spot?
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उत्तर
The yellow spot has more cones and less rod cells. The blind spot has no photosensitive cells.
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संबंधित प्रश्न
Millions of people in the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organised a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission, how would you contribute in this noble cause?
(i) State the objective of organising such campaigns.
(ii) List two arguments which you would give to motivate the people to donate their eyes after death.
(iii) List two values which are developed in the persons who actively participate and contribute in such programmes.
Name one defect of vision (or eye) which cannot be corrected by any type of spectacle lenses.
An eye has a far point of 2 m. What type of lens in spectacles would be needed to increase the far point to infinity? 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 a young man
What is meant by optical illusion? Give one example.
Choose the correct answer :
Presbyopia is a disease of _____________
Name the following:
The defect of the human eye caused due to the uneven surface of the cornea.
Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
Name the following:
Two kinds of accomodations.
