1 Mark Questions
1. Radius of the curvature of convex mirror 40 cm and the size of the object is twice as that of the image. Then, what is the image distance?
2. When a mirror is rotated through an angle θ, what is the angle turned by the reflected ray?.
3. A concave mirror of focal length f produced an image n size of the object. If the image is real, what is the distance from the mirror?
4. The angle between incident ray and the reflect ray is 70°. What if the angle of incidence?
5. A 5 cm tall object is placed 10 cm from a concave mirror of focal length 15 cm. Find the position, nature and the size of the image.
6. A tall man of height 6 feet want to see his image. Find the required minimum length of the mirror to see his image.
7. Where should an object be placed in front of concave mirror focal length f so that the image to be the same size as the object?
8. What is the magnification produced a plane mirror? 9. If the power of a lens is +5 dioptres, what is the focal
length?
10. A parallel beam of light is incident on a concave lens of large aperture, Will the reflected coverage at point? 11. Which of the two main parts of an optical fiber has a
higher value of refractive index?
12. A thin prism of 60° angle gives a deviation of 30°. What is the refractive index of material of prism?
13. What is the refractive index of air for light waves? 14. Mention two conditions of total internal reflection? 15. What happens when white light passes through a
prism?
16. What is a prism?
17. Show the refraction of light by a prism with a suitable diagram.
18. Give two characteristic properties when the prism is in the position of minimum deviation?
19. Which of the following colours suffers maximum deviation in a prism?
20. What is the importance of linear magnification?
21. Where should an object placed in image of the same by a convex lens? Can it happen in case of a concave lens?
22. How will you judge whether a given piece of glass is convex lens, concave lens or a plane glass sheet? 23. A lens whose radii of curvature are different is forming
an image. If the lens is reversed, will the position of image change?
24. What is the nature of the image formed by a concave mirror when the object is placed between its pole and focus?
25. Focal length of an equiconvex lens is equal to the radius of curvature of either face. What is the refractive index of lens material?
26. What should be the position of an object relative to a biconvex lens so that it behaves like a magnifying lens? 27. A converging and a diverging lens of equal focal lengths
are place coaxially in contact. Find the power and focal length of the combination.
28. When a biconvex lens made of glass (µ = 1.5) is immersed in water (µ = 1.33), what will happen to its focal length?
2 Marks Que stions
29. What happen when a monochromic ray passes through a prism?
30. State the law of reflection.
31. What do you mean by the spherical aberration of a lens? How can it be minimized?
32. Define linear magnification?
33. Mention the use of plane, concave and the convex mirror.
34. An object is placed between the focus and the pole of a concave mirror. Locate the position of the image by the ray diagram.
35. What is mean by the linear magnification?
36. Give new Cartesian sigh convention for the spherical mirrors.
37. A ray of light incident on one face of an equilateral prism undergoes total internal reflection at another face. If the refractive index of prism material is 2 then, find the angle of incidence (r2) at another face is
38. A ray is incident at an angle of incidence i on one surface of a prism of small angle A and emerges normally from the opposite face. If the refractive index of the prism material is µ, then what angle of incidence? 39. If the angle of a prism is 60° and angle of minimum
deviation is 40°. Then find the angle of refraction. 40. Refractive index of glass for light of yellow, green and
red colours are µy, µg and µr respectively. Rearrange
these symbols in an increasing order of values? 41. At what angle of incidence should a light beam strike a
glass slab of refractive-index 3 , such that the reflected and the refracted rays are perpendicular to each other?
42. Show with the help of a diagram the deviation produced by a prism.
43. Define a monochromatic and polychromatic light. How can one obtain monochromatic light from polychromatic light?
44. How deep will a 4 m deep tank appear when seen in air due to optical illusion? Refractive index of water is 4/3. 45. What is dispersion?
46. A concave lens of f = 15 cm forms an image 10 cm from the lens. Prove that the object is placed 30 cm away from the lens.
47. An object is placed 10 cm in front of a lens. The lens forms a real image three times magnified. Where is the image formed? What is the focal length of the lens? 48. The radius of curvature of either face of a convex lens
is equal to its focal length. What is the refractive index of the material of the lens?
49. Calculate the focal length of the combination of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm. Is the system a converging or a diverging lens?
50. A compound microscope with an objective of 1.0 cm focal length and an eye-piece of 2.0 cm focal length has a tude length of 20 cm. calculate the magnifying power of the microscope, if the final image is formed at the neat of the eye.
51. An astronomical telescope, in normal adjustment position has magnifying power 5. The distance between the objective and the eye-piece is 120 cm. calculate the focal lengths of the objective and of the eye-piece. 52. A convex lens of refractive index n1 is held in a
medium of refractive index n2 . trace the path of
refracted rays of parallel beam of light incident on the lens when (i) n2>n1 and (ii) n2=n1.
53. Using the lens formula, show that a concave lens produces a virtual and diminished image independent of the location of object.
3 Marks Questions
54. An object is placed 10 cm in front of a concave mirror of focal length 15 cm. Find the nature, position and size of the image.
55. An erect image three times the size of the object is obtained with the concave mirror of radius of curvature 36 cm. What is the position of the object?
56. Light of wavelength 5000 A0 fall on a reflection surface. What are the wave length and frequency of reflected ray normal the incident ray?
57. What type mirror will you prefer for the saving or make –up?
58. For dividing a car, which type of mirror would you prefer to see the traffic at your back?
59. What is the difference between virtual image formed by the plane, concave and convex mirror?
60. Described a simple method of finding the focal length of a concave mirror.
61. What are spherical aberration?
62. What do you understand by diffuse reflection?
63. Draw three important rays for a concave mirror that are generally used to locate the position of the image of an object?
64. Define the dispersive power of a prism. 65. Why does the s ky appear blue?
66. A ray of light falls normally on the face of a prism of refractive index 1.5. Find the angle of the prism if the ray just fails to emerge from the second face.
67. The minimum deviation produced by a glass prism having an angle of 60° is 30°. If the velocity of light in air is 3 × 108 ms–1, calculate its velocity its velocity in glass.
68. A glass prism has a refracting angle of 60°. The angle of minimum deviation is 40°. Find the refractive index.
At what angle the ray of light should be incident so as to suffer minimum deviation?
69. A ray of light enters a rectangular glass slab of refractive index 3 at an angle of incidence 60°. It travels a distance 5 cm inside the slab and emerges out of the slab. What is the perpendicular distance between the incident and emergent rays?
70. Prove that the refractive index of denser medium w.r.t. rarer medium is equal to the reciprocal of the refractive index of rarer medium w.r.t. denser medium.
71. An object is immersed in water, show that a
w
Realdepth Apparent depth
µ =
72. Describe two applications of atmospheric refraction. 73. A myopic person has been using spectacles of power—
1.0 dioptre for distant vision. During old are he also needs to use separate reading glass of power +2.0 dioptre. Explain what may have happened.
74. A spherical surface of radius of curvature R separates air (refractive index 1.0) from glass (refractive index 1.5). The centre of curvature is in the glass. A point object P placed in air is found to have a real image Q in the glass. The line PQ cuts the surface at point O and PO = OQ. Find the distance of the object from the spherical surface.
75. A small point object is placed in air at a distance of 60 cm from the convex spherical refracting surface of refractive index 1.5. If the radius of the curvature of the spherical surface is 25 cm, find the position of the image and power of the refracting surface.
76. An ink dot marked on the surface of glass sphere placed in air is viewed
Fig
through the glass from a position directly opposite. If the diameter of the sphere is 15 cm and the refractive index of glass is 1.5, find the position of the image.
77. A convex refracting surface of radius of curvature 15 cm separates two media of refractive indices 4/3 and 1.5. An object is kept in the first medium at a distance of 240 cm from the refracting surface. Calculate the position of the image.
78. A real image of an object id formed at a distance 20cm from a lens. On putting another lens in contact with it, the image is shifted 10 cm toward the combination. Determine the power of the second lens.
79. How does the focal length of a convex lens change if monochromatic red light is used instead of monochromatic blue light?
80. Draw a ray diagram of an astronomical telescope in the normal adjustment position. Write down the expression for its magnifying power.
81. Draw a ray diagram of an astronomical telescope in the near adjustment position. Write down the expression for its magnifying power.
82. Explain why does a convex lens behave as a converging lens when immersed in water (µ = 1.33) and as a diverging lens, when immersed in carbon disulphide (µ = 1.6).
5 Marks Questions
83. Obtain the relation between radius of curvature (R) and the focal length (f) of a convex mirror?
84. A 2.0 cm tall is placed 15 cm from a concave mirror of focal length 10 cm. Find the position, size and nature of the image?
85. Two planes are mirror are inclined to each at angleθ. A ray of light is reflected first at one mirror and mirror then at the other. Fined the total deviation of the ray and show that it is independent of the angle of the incidence at first t mirror.
86. A square wire of side 3.0 cm is placed 25 cm away from a concave mirror of focal length is on the axis of the mirror with the two sides normal to the axis.
87. Two objects A and B when the placed in front of the concave mirror of focal length 7.5 cm give the image of equal size If A is three times the size from the mirror of B and is place 30cm, Find the distance of the object from the pole of the mirror,
88. The angle of minimum deviation for yellow light in a prism of refractive index 1.6 is found to be 46°. Calculate the refracting angle of the prism.
89. In a spectrometer, for the prism A = 60°, calculate the angle of minimum deviation if µ of the prism for orange light is 1.64?
90. Define critical angle, obtain a relation for it. Define total internal reflection. State essential conditions for its occurance.
91. A ray of light is incident at an angle of 60° on one face of a prism which has an angle of 30°. The ray emerging
out of the prism makes an angle of 30° with the incident ray. Show that the emergent ray is perpendicular to the face through which it emerges and calculate the refractive index of the material of the prism.
92. A ray of monochromatic light is incident on the refracting face of a prism of refracting angle 75°. It passes through the prism and is incident on the other face at the critical angle. If the refraction index of the prism is 2, find the angle of incidence on the first face of the prism.
93. A glass prism of angle 72° and refractive index 1.66 is immersed in a liquid of refractive index 1.33.Find the angle of minimum deviation for a parallel beam of light passing through the prism.
94. An object is placed 20 cm to the left of a convex lens of focal length 10 cm. If a concave mirror of focal length 5 cm is placed 30 cm to right of the lens, what is the position of the final image?
95. A diverging lens of focal length 20 cm is placed 60 cm from a pin and a concave mirror of radius of curvature 20cm is placed on the opposite side of the lens. Where should the mirror be placed so that image of the pin may coincide with the pin itself?
96. With the help of the data shown in the ray diagram in fig, calculate the focal length of the concave lens.