3 Mark Questions:-
1. What is the quantitative meaning attached to the term’ power of accommodation’ ? Why can’t we see clearly objects that are too close to the eye ? When do you have the least strain on the muscles of a normal eye ?
2. What is (i) cataract (ii) near point (iii) presbyopia.
3. What is the role of (i) ciliary muscle (2) iris (3) pupil (4) eye lens (5) light sensitive cells (6) retina
4. The near point of a hypermetropic person is 75 cm from the eye. What is the power of the lens required to enable him to read clearly a book held at 25 cm from the eye.
5. (i) A student allows a stream of white light passed through a medium of tiny particles. Which colour will get scattered the most ?
(ii) The refractive indices of diamond and rock salt are 2.42 and 1.54 respectively. If the speed of light in diamond is 1.2 X 108 ms-1, find the speed of light in rock salt.
6. (i) Four students observed an image and concluded that it is virtual, enlarged and erect. What is the nature of the reflecting/refracting surface ?
(ii) A convex mirror used on bus has a focal length of 200 cm. If a scooter is located at 100 cm from this mirror, find the position, nature and magnification of the image formed in the mirror.
7. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the total length of the lens.
8. (i) Define refractive index of a medium.
(ii) Draw diagrams to show the path of ray of light when it goes from (a) air to glass (b) water to air.
9. A person is unable to see the objects beyond 2 cm, clearly cause due to which this detect may arise. Draw ray diagrams to show (i) this defect of vision (ii) correction of this detect using appropriate lens.
10. Draw diagrams to show the refraction of yellow coloured light through a (i) rectangular glass slab (ii) a triangular glass prism.
5 Mark Questions:-
Give reasons for the following.
1. Stars appear to twinkle
2. Sun appear reddish early in the morning
3. Sky appear dark instead of blue to an astronaut
4. Blue colour of sky
5. Danger signal lights are red in colour.
(i) Name the type of mirror used in the following situations (a) Head light of a car (b) rear-view mirror of a vehicle (c) to see a full length image of a tall building. (d) 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.
(i) magnification produced by a lens is – 2. What does this mean.
(ii) (a) Two lenses have power of (i) + 2D (ii) – 4D, what is the nature and total length of each lens ?
(a) An object is kept at a distance of 100 cm from each of above lenses. Calculate the (i) image distance (ii) magnification in each of the two cases.
4. What is meant by dispersion of white light ? Describe the formation of rainbow in the sky with the help of a diagram. In dispersion of white light through prism, which colour deviates most and which colour the least? Why do they deviate differently ?
1. What is the quantitative meaning attached to the term’ power of accommodation’ ? Why can’t we see clearly objects that are too close to the eye ? When do you have the least strain on the muscles of a normal eye ?
2. What is (i) cataract (ii) near point (iii) presbyopia.
3. What is the role of (i) ciliary muscle (2) iris (3) pupil (4) eye lens (5) light sensitive cells (6) retina
4. The near point of a hypermetropic person is 75 cm from the eye. What is the power of the lens required to enable him to read clearly a book held at 25 cm from the eye.
5. (i) A student allows a stream of white light passed through a medium of tiny particles. Which colour will get scattered the most ?
(ii) The refractive indices of diamond and rock salt are 2.42 and 1.54 respectively. If the speed of light in diamond is 1.2 X 108 ms-1, find the speed of light in rock salt.
6. (i) Four students observed an image and concluded that it is virtual, enlarged and erect. What is the nature of the reflecting/refracting surface ?
(ii) A convex mirror used on bus has a focal length of 200 cm. If a scooter is located at 100 cm from this mirror, find the position, nature and magnification of the image formed in the mirror.
7. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the total length of the lens.
8. (i) Define refractive index of a medium.
(ii) Draw diagrams to show the path of ray of light when it goes from (a) air to glass (b) water to air.
9. A person is unable to see the objects beyond 2 cm, clearly cause due to which this detect may arise. Draw ray diagrams to show (i) this defect of vision (ii) correction of this detect using appropriate lens.
10. Draw diagrams to show the refraction of yellow coloured light through a (i) rectangular glass slab (ii) a triangular glass prism.
5 Mark Questions:-
Give reasons for the following.
1. Stars appear to twinkle
2. Sun appear reddish early in the morning
3. Sky appear dark instead of blue to an astronaut
4. Blue colour of sky
5. Danger signal lights are red in colour.
(i) Name the type of mirror used in the following situations (a) Head light of a car (b) rear-view mirror of a vehicle (c) to see a full length image of a tall building. (d) 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.
(i) magnification produced by a lens is – 2. What does this mean.
(ii) (a) Two lenses have power of (i) + 2D (ii) – 4D, what is the nature and total length of each lens ?
(a) An object is kept at a distance of 100 cm from each of above lenses. Calculate the (i) image distance (ii) magnification in each of the two cases.
4. What is meant by dispersion of white light ? Describe the formation of rainbow in the sky with the help of a diagram. In dispersion of white light through prism, which colour deviates most and which colour the least? Why do they deviate differently ?
5. (a) With the help of a ray diagram, show the type of images formed when object is placed at the following positions in front of concave mirror.
(a) Between F and C (b) at F
(b) The radius of curvature of convex mirror, used on a moving automobile is 2.0 m. A truck is coming behind it at a constant distance of 3.5 m. Calculate (i) the position and (ii) the size of image relative to the size of the truck. What will be the nature of the image ?
6. (i) Draw a ray diagram to show passage of a ray of light through a rectangular glass slab, when the angle of incidence is zero.
(ii) what you mean by lateral displacement, Write any two factors on which it depends.
(c )with the help of an activity demonstrate the scattering white light.
7. (a) It is required to get (i) a magnified, erect and virtual image (ii) a diminished, erect and virtual image of a given object. What type of lens should we use in each case and where should the object be kept ?
(b) Draw ray diagrams to show the required image formation in each case.
(c) Which of these lenses could also form a magnified, real and inverted image ? Also indicate the position of the object for which this could happen ?
8. Draw a ray diagram in each case to show the position and nature of the image formed when the object is placed.
(i) at the centre of curvature of a concave mirror.
(ii) between the pole and focus of a concave mirror.
(iii) in front of a convex mirror
(iv) at 2F of a convex lens
(v) in front of a convex lens.
9. A convex lens is being used to get a three-fold magnified image of an object. The lens has a power of + 4.0D. Find the two positions of the object for this magnification and show the image formation in each case through the appropriate ray diagram.
10. A concave mirror produces three times magnified (enlarged) real image of an object 10 cm infront of it. Where is the image located ?(a) Between F and C (b) at F
(b) The radius of curvature of convex mirror, used on a moving automobile is 2.0 m. A truck is coming behind it at a constant distance of 3.5 m. Calculate (i) the position and (ii) the size of image relative to the size of the truck. What will be the nature of the image ?
6. (i) Draw a ray diagram to show passage of a ray of light through a rectangular glass slab, when the angle of incidence is zero.
(ii) what you mean by lateral displacement, Write any two factors on which it depends.
(c )with the help of an activity demonstrate the scattering white light.
7. (a) It is required to get (i) a magnified, erect and virtual image (ii) a diminished, erect and virtual image of a given object. What type of lens should we use in each case and where should the object be kept ?
(b) Draw ray diagrams to show the required image formation in each case.
(c) Which of these lenses could also form a magnified, real and inverted image ? Also indicate the position of the object for which this could happen ?
8. Draw a ray diagram in each case to show the position and nature of the image formed when the object is placed.
(i) at the centre of curvature of a concave mirror.
(ii) between the pole and focus of a concave mirror.
(iii) in front of a convex mirror
(iv) at 2F of a convex lens
(v) in front of a convex lens.
9. A convex lens is being used to get a three-fold magnified image of an object. The lens has a power of + 4.0D. Find the two positions of the object for this magnification and show the image formation in each case through the appropriate ray diagram.
Pls give the solutions for this
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