Question 13 Marks
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
Questions
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Question 23 Marks
1. Write the function of each of the following parts of human eye : cornea, iris, crystalline lens, ciliary muscles.
2. Millions of people of the developing countries of world are suffering from corneal blindness. These people 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?
1. State the objective of organising such campaigns.
2. List two arguments which you would give to motivate the people to donate their eyes after death.
3. List two values which are developed in the persons who actively participate and contribute in such programme.
2. Millions of people of the developing countries of world are suffering from corneal blindness. These people 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?
1. State the objective of organising such campaigns.
2. List two arguments which you would give to motivate the people to donate their eyes after death.
3. List two values which are developed in the persons who actively participate and contribute in such programme.
Answer
View full question & answer→1. Functions of following parts of human eye are given below:
1. Cornea - It is a thin membrane which provides $67 \%$ of the eye's focussing power.
2. Iris - It controls amount of light entering the eye by controlling the size of pupil similar to the aperture of a camera which has capacity to decrease or increase the amount of light entering eye.
3. Crystalline lens - It helps to focus light on retina for image formation.
4. Ciliary muscles - It contracts and relax in order to change the lens shape for focussing image at retina. when it contracts the lens become thicker and when it relaxes the lens become flat.
2. 1. The objective of organising such compaigns is to guide, educate and help those people who are suffering from corneal blindness that they can be cured by corneal replacement surgery.
2. 1. Come to participate in this campaign because, if someone get his vision through your eyes, it is an incredible help. 2. As eye is one of the most valuable sense organs through which an individual can achieve so many things in his/her life, so try to realise the situation that these people are suffering from.
3. The persons who actively participate and contribute in such programme are strong hearted and very much helpful for the people living in such situations.
1. Cornea - It is a thin membrane which provides $67 \%$ of the eye's focussing power.
2. Iris - It controls amount of light entering the eye by controlling the size of pupil similar to the aperture of a camera which has capacity to decrease or increase the amount of light entering eye.
3. Crystalline lens - It helps to focus light on retina for image formation.
4. Ciliary muscles - It contracts and relax in order to change the lens shape for focussing image at retina. when it contracts the lens become thicker and when it relaxes the lens become flat.
2. 1. The objective of organising such compaigns is to guide, educate and help those people who are suffering from corneal blindness that they can be cured by corneal replacement surgery.
2. 1. Come to participate in this campaign because, if someone get his vision through your eyes, it is an incredible help. 2. As eye is one of the most valuable sense organs through which an individual can achieve so many things in his/her life, so try to realise the situation that these people are suffering from.
3. The persons who actively participate and contribute in such programme are strong hearted and very much helpful for the people living in such situations.
Question 33 Marks
Find the focal length of a lens of power -2.0 D . What type of lens is this?
Answer
View full question & answer→$\mathrm{f}=\frac{1}{P}=\frac{1}{-2}=-0.5 \mathrm{~m}$
$\mathrm{f}=-0.5 \mathrm{~m}=-50 \mathrm{~cm}$
Lens is divergent or say concave.
$\mathrm{f}=-0.5 \mathrm{~m}=-50 \mathrm{~cm}$
Lens is divergent or say concave.