Question Bank on Light

01. How do we see the things in light?
02. Write the different properties of light?
03. What are the different optical phenomena that takes place due to light?
04. Deflection of light?
05. State laws of reflection of light?
06. What are the properties of the image formed by a plane mirror?
07. What are the two types of spherical mirrors?
08. What is a concave mirror and convex mirror?
09. Define the following of a spherical mirror?
a) pole b) centre of curvature c) Principal focus d) Principal axis e) Radius of curvature f ) aperture g) focal length

10.What is the relationship between the radius of curvature and focal length?
10. A ray of light makes an ∟30° to the normal. Find out what angle does a reflected ray from a plane mirror will make with respect to the reflecting surface? 11. What is the angle of reflection of an incident ray that travels along the normal to the reflecting surface? Why? 12. A ray of light makes an angle of 40° with respect to the principle axis of a concave mirror. Find out what will be the angle subtended by the reflected ray with respect to the principle axis? Why? 13. A ray traveling parallel to the principle axis hits a point M on the concave mirror. If the ray makes an angle of 30° to the line drawn from M to the centre of curvature what will be the angle made by the reflected ray that passes through the principle focus after reflection with respect to the same line? Why? And how do you call the line? 14. If a paper is kept for a long time at the principle focus of a concave mirror exposed to the sunlight what will happen to the paper? Explain. 15. For spherical mirror of small aperture where does the principle focus lie? 16. With a suitable diagram write the important rules to be followed to draw the ray diagram for a concave mirror. 17. Complete the given ray diagram

18. Draw a ray diagram for a spherical mirror which forms a real image of magnification less than one 19. Draw a ray diagram for a spherical mirror which forms a real image of magnification more than one 20. Draw a ray diagram for a spherical mirror which forms a virtual image of magnification less than one 21. Draw a ray diagram for a spherical mirror which forms a virtual image of magnification more than one 22. Draw a ray diagram for the spherical mirrors for the object at infinity 23. How does the nature and position of the image change when the object recedes a concave mirror and convex mirror 24. Definition linear magnification

25. Write the mirror formula and formula to find out linear magnification 26. Draw a ray diagram for a spherical mirror for m=1 for real image 27. Write the new Cartesian convention rules with a diagram. 28. A concave mirror forms a real image at a distance of 25 cm for an object distance of 50 cm. Calculate the focal length of the mirror and its radius of curvature. Calculate the magnification produced by the mirror. 29. What are the uses of a concave mirror and a convex mirror? 30. Why cannot a dentist use a convex mirror as his clinical mirror instead of a concave mirror? 31. Why cannot a plane mirror be used as a rear view mirror? 32. Why cannot a concave mirror be used as a rear view mirror? 33. The focal length of a concave mirror and a convex mirror is 25 cm. If an object is kept at a distance of 40cm from both of them calculate the image distance due to the mirrors individually and the magnification produced by both of them. 34. The magnification produced by a mirror is 4 for both type of images in two different cases. If the radius of curvature of the mirror is 40cm calculate the object distance and image distance for both the cases

35. The magnification produced by a mirror is 0.25 for an image formed in the other side of the mirror. If the distance of the image from the mirror is 10cm calculate the radius of curvature of the mirror and also identify the mirror.

36. A dentist uses a mirror in front of a decayed tooth at a distance of 4cm from the tooth to get a 4 times magnified image on the mirror. Calculate the radius of curvature of the mirror. If he keeps the mirror in front of a candle at a distance of 80cm calculate what type of image does it forms and where does it form? 37. A person sitting in front of a saloon shaving mirror notices that the rays light from the sun falls on a near by wall as a sharp and bright spot at a distance 2m from the mirror. At one instance of time he sits in front of the mirror at a distance of 1m and at another instance he moves 1m away from his position. Calculate the image distances and magnification and type due to his positions in front of the mirror. And draw a ray diagram for both of the positions. 38. A stationary motorist notices an approaching car on his rear view mirror in two different instance at a time interval of 5 seconds. The magnification of the car changes from 0.25cm to 0.5cm in that time. If the focal length of the mirror is 1m calculate the speed of the car.

39. There is a guiding mirror in the hairpin bend of a narrow hilly road. At an instance of time two cars traveling towards the mirror notices each other on the mirror of radius of curvature 2m. If the distance of the image of car A is formed at a distance of 50cm from the mirror and the other is 100cm from the mirror calculate the distances of the cars from the mirrors. If they travel with uniform speed which of the cars will reach the bend quickly. 40. If a concave mirror of focal length 10cm forms an image at a distance of 20cm calculate the distance of object from the mirror 41. If a convex mirror of radius of curvature 100cm has its object at distance 2m calculate the magnification produced by the mirror 42. How does the image position and size change if the object is moved away from a concave mirror and a convex mirror? 43. The magnification produced by a mirror for an image formed on the mirror changes from 0.4 to 0.2. If the focal length of the mirror is 20cm calculate the distance through the object moved. 44. The magnification produced by a mirror for an image formed on the wall changes from 0.4 to 0.2 . if the focal length of the mirror is 40cm calculate the distance through the object moved. If the object has to produce a 5 times magnified image due to the movement of the object in the same direction calculate the distance through which the object has to be moved and its distance from the mirror.

45. A mirror forms a 2cm image of a 4cm object in the same side of the mirror. If the radius of curvature of the mirror is 50 calculate the distance between the object and the mirror and the image and the mirror 46. A concave mirror of radius curvature 40cm produces 0.5times magnified image of an object. If a convex mirror of same radius of curvature is replaced in that place how does the magnification, position and type of the image change? 47. A mirror forms a 4cm tall image of a 2cm object in the same side of the object. If the distance between the principle focus and the centre of curvature of the mirror is 20cm calculate the nature, position of the image 48. A mirror forms a 6cm tall image of a 2cm object in the other side of the mirror. If the distance between the image and the mirror is 20cm calculate the focal length of the mirror 49. A mirror forms a 2cm tall image of a 6cm object in the other side of the mirror. If the distance between the image and the mirror is 10cm calculate the focal length of the mirror 50. What is the reason for the apparent flattening of a lemon when it is kept in a tumbler of water? 51. Define refraction and the laws of refraction of light

52. Will there be a difference between the observation of the floor of the bottom of the swimming pool when it is empty and when it is filled with water. 53. Will there be a change in the bending of a pencil kept in a glass of water when it is observed from outside to that of a glass of kerosene. Why? 54. Draw the ray diagram for the refraction through a glass slab and show that angle of incidence is equal to angle of refraction 55. Define lateral displacement and what are the factors on which the lateral displacement depends on? 56. A ray of light travels from medium A to medium B. The velocity of light in A is twice of B. If its velocity still increases in another medium C compare the angles of refraction of the ray light in medium B and C 57. A ray of light travels from medium A to B and further to medium C. If the speed of light in medium B is less than in medium C compared to that of A compare the angle of refraction in B and C 58. A ray of light travels from medium A to B and has its angle of refraction greater than its angle of incidence. Find out in which medium its speed is less. 59. A ray of light travels from medium from a transparent substance A to another transparent substance B. If the angle of incidence is equal to angle of refraction what do you think about the mediums and their refractive indices? 60. State Snells’ law.

61. What do you mean by absolute refractive index?
62. How do you define the term refractive index?

63. A ray of light travels from diamond of refractive index 2.42 to water of refractive index 1.33. Calculate the refractive index of water to diamond and diamond to water. In which of the medium the light travels with greater speed? How does the ray of light bend in water? 64. There two pairs of medium AB and AC. For the given angle of incidence the angle of refraction in the second pair is less than the angle of incidence but in other case the angle of refraction is greater. Of the both B and C which one is denser? 65. The absolute refractive index of medium A is 2.4 and the absolute refractive index of medium B is 1.2. A ray of light is incident is on A at an angle of 30° calculate the angle through which the ray gets refracted? 66. The absolute refractive index of kerosene is 1.44. Calculate the velocity of light in kerosene. 67. The speed of light in water is 2.5×108 m/s. If a ray of light travel from water to Ruby of refractive index 1.7 calculate the velocity of light in Ruby if the refractive index of water is 1.3. 68. A ray of light travels with a speed of 2×108 m/s in a medium X and if its speed is halved in another medium Y calculate the refractive index of medium X to Y and Y to X

69. A ray of light travels with a speed of 1.5x108m/s in medium X and travels with a speed of 2×108 m/s in another medium Y. If the absolute refractive index of medium Y is 1.52 calculate the refractive index of other medium. 70. A red ray of light is incident at angle of x on a glass-air interface. If the red light is replaced by a violet light will there be any change in the angle of refraction. Explain. 71. A ray of light makes angle emergence 45° at a glass- air interface. What is the angle of incidence for the ray of light at air-glass interface. 72. A ray of light is incident on the breadth side of a glass slab and on the length side of the same glass slab in another incidence. In which case the lateral shift will be more.

Why 73. If a green ray of light is replaced by a blue light for the given angle of incidence on the glass slab how does the lateral shift change? 74. ABCD is a square glass slab. If the ray of light is incident on AB side and CD side in two different sides in which of the incident the lateral shift will be more? 75. ABCD is a rectangular hollow glass slab. If the ray of light is incident at an angle of 45° what will be the angle of emergence. (The slab is a thin walled slab) 76. ABCD is a rectangular hollow glass slab. In an instance it is filled with water and in another instance it is filled with turpentine. For the given angle of incidence in which of the cases the lateral shift will be more. Why? 77. Are optical density and mass density same. If not justify.

78. What is a lens. And what are the two prominent types of lenses that we use in the lab. How will you identify them physically and with its property? 79. A boy while playing with a convex lens looks at a printed paper through the lens in two different places of the paper A and B. At A he notices that the letters of the printed matter appear bigger and at B the paper starts to burn. Which of the places A or B is closer to the lens and why? 80. Define the optic centre, focal length, principle axis, radius of curvature, power, principle focus, aperture and centre of curvature of a lens. 81. Write the new Cartesian sign convention rules for a lens with a diagram. 82. Write the formula for a lens and the formula for magnification for a lens. 83. Why is the power of a convex lens is positive and concave lens is negative 84. Define one dioptre.

85. Write the rules to be followed to draw the ray diagram for a lens with diagram 86. Draw the ray diagram for a lens which forms a virtual magnified image. 87. Draw the ray diagram for a lens which forms a virtual diminished image. 88. Draw the ray diagram for a lens which forms a real image of magnification one 89. Draw the ray diagram for a lens which forms a real diminished and real enlarged image. 90. What happens to the image position and size when an object recedes from a convex lens and concave lens. 91. Complete the given ray diagrams.

88.Complete the given ray diagrams.
92. An object is kept at a distance of 30cm from a convex lens of focal length 15cm. Calculate the distance at which the image formed and its magnification. 93. An object is kept at distance of 40cm from a convex lens which forms an image at a distance of 20cm. Calculate the power and focal length of the lens. 94. The power of a convex lens is 10D. If it forms a real image at a distance of 40cm from the lens calculate the place where the object is placed. 95. An object is kept at a distance from lens of power 10D which forms a virtual image at distance of 5cm from the lens. Calculate the distance at which the object is placed 96. An object is kept at a distance of a lens of power 10D which forms a virtual image at a distance of 20cm from the lens. Calculate the distance at which the object is placed 97. A concave lens of focal length 30cm has its object at a distance of 60cm from it. Calculate its power. 98. A lens of power 5D forms an image in the same side of the object at a distance of 15cm from the lens.

If another lens of another type is kept in the same place for the same object distance how does the image nature, position, distance and magnification of the object change due to the second lens. 99. Two lenses A and B forms a 2cm tall image of an object of height 6cm in two instances. If A forms the image in the same side of the object and B in the other side of the lens calculate the power of the lenses for the given object distance of 20cm for the both. 100. A lens of focal length 20cm forms a magnification of 4 for the given object in two different instances A and B. Calculate the distance through which the object is moved in these two different instances. 101. A lens of power 10D forms an image of magnification 5 for an image in the same side of the object. If the object is moved 40cm away from the lens how does the image size, nature and position change? 102. The magnification due to a lens of focal length 20cm for a real image changes from 0.2 to 2 Calculate the distance through which the object is moved.