Tiêu đề 28. Ray Optics Medium.pdf ✅

1. The wavelength of light belongs to the .......... part of the spectrum: (a) Visible (b) Ultraviolet (c) Infrared (d) Both (a) and (c) 2. A boy of height I m stands in front of a convex mirror. His distance from the mirror is equal to its focal length. The height of his image is : (a) 0.25m (b) 0.33m (c) 0.5m (d) 0.67m 3. A concave shaving mirror has a radius of curvature of 35.0cm.It is positioned so that the (upright) image of a man’s face is 2.50 times the size of the face. How far is the mirror from face? (a) 5.25 cm (c) 21.0 cm (b) 10.5 cm (c) 42 Cm 4. When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10cm. If the object is moved with a speed of 9 1 sm− the speed with which image moves is: (a 1 10ms − (b) 1 1ms − (c) 1 9ms− (d) 1 0.9ms− 5. What can be the largest distance of an image of a real object from a convex mirror of radius of curvature is 20cm? (a) 10 cm (b) 20 cm (c) Infinity (d) Zero 6. An object 2 cm high is placed at a distance of16 cm from a concave mirror, which produces a real image 3 cm high. What is the focal length of the mirror? (a) -9.6 cm (b) -3.6 cm (c) -6.3 cm (d) -8.3 cm 7. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way the its and closer to the pole is 20 cm away from the mirror the length of the image is: (a) 10 cm (b) 15 cm (c) 2.5 cm (d) 5 cm 8. A point luminous object (O) is at a distance h from front face of a glass slab of width d and of refractive index  .On the back face of slab is a reflecting plane mirror. An observer sees the image of object in mirror as shown in figure. Distance of image from front face as seen by observer will be: (a)  + 2d h (b) 2h+2d (c) h + d (d)  + d h 9. Which of the following is correct for the beam which enters the medium? (a) Travel as a cylindrical beam (b) Diverge (c) Converge (d) Dover near the axis and converge near the periphery 10. Refraction of light from air to glass and from air to water are shown in figure (i) and figure (ii) below. The value of the angle in the case of refraction as shown in figure (iii) will be (i) figure (ii) figure (iii) figure: (i) (ii) (iii) (a) 0 30 (b) 0 35 (c) 0 60 (d) 41o 11. A vessel depth x is half filled with oil of refractiveindex index 1 and the other half is filled with water of refractive index 2 The apparent depth of the vessel when viewed from above is: (a) 1 2 1 2 2 x( )    +  (b) 2( ) x 1 2 2    +  (c) ( ) x 1 2 1 2    +  (d) 1 2 1 2 2x( )    +  12. Three immiscible liquids of densities d1  d2  d3 and refractive indies 1  2  3 are put in a beaker. The height of each liquid column is h/3.A dot is made at the bottom of the beaker. For near normal vision, find the apparent depth of the dot.: (a)          +  + 1 2 3 1 1 1 6 h (b)          −  − 1 2 3 1 1 1 6 h (c)          −  − 1 2 3 1 1 1 3 h (d)          +  + 1 2 3 1 1 1 3 h 13. A ray light strikes a transparent rectangular slab of refractive index 2 at an angle of incidence of 450 . The angle between the reflected and refracted rays is : (a) 750 (b) 900 (c) 1050 (d) 1200 14. A ray of light is incident on a thick slab of glass of thickness t as shown in the figure. The emergent ray is parallel to the incident ray but displaced sideways by a distance d. If the angles are small then d is, :
(a)       − r i t 1 (b)       − r i rt 1 (c)       − i r it 1 (d)       − i r t 1 15. A tank is filled with to a height of 15.5 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 8.5 cm. if water is replaced by a liquid of refractive index 1.94 upto the same height, by what distance would the microscope same height, by what distance would the microscope have to be moved to focus on the needle again? (a) 1.00 cm (b) 2.37 cm (c) 0.52 cm (d) 3.93 cm 16. A ray incident at a point at an angle of incidence of 600 enter a glass sphere of refractive index 3 and is reflected and refracted at the farther surface of the sphere. The angle between the reflected and refracted rays at this surface is : (a) 500 (b) 600 (c) 900 (d) 400 17. Mirage is a phenomenon due to: (a) Refraction of light (b) Reflection of light (c) Total internal reflection of light (d) Diffraction of light. 18. Critical angle of glass is 1 and that of water is 2 . The critical angle for water and glass surface would be ( g = 3/ 2w = 4 / 3 ). (a) Less than 2 (b) Between 1 and 2 (c) Greater than 2 (d) Less than 1 19. Light travels in two media A and B with speeds 8 1 8 1 1.8 10 ms and2.4 10 ms − −   respectively. Then the critical angle between them is: (a)      −  3 2 sin 1 (b)      −  4 3 tan 1 (c)      −  3 2 tan 1 (d)      −  4 3 sin 1 20. A point source of light is placed at a depth of h below the surface of water of refractive index  . A floating opaque disc is placed on the surface of water so that light from the source is not visible from the surface. The minimum diameter of the disc is: (a) 2 1/ 2 ( 1) 2h  − (b) ( ) 1/ 2 2 2h  −1 (c) 2 1/ 2 2( 1) h  − (d) ( ) 1/ 2 2 h  −1 21. Critical angle for light going form medium (i) to (ii) is  . Thespedoflight in medium (i) is v, then then speed of light in medium (ii) is: (a) v(1− cos) (b) sin v (c) cos v (d) (1 sin ) v −  22. For a total internal reflection, which of the following is correct? (a) Light travel from rarer to denser medium. (b) Light travel from denser to rarer medium. (c) Light travel in air only. (d) Light travel in water only. 23. An air bubble in a glass sphere(  =1.5 ) is situated at a distanced 3 cm form a convex surface of diameter 10 cm. At what distance from the surface will the bubble appear? (a) 2.5 cm (b) -2.5 m (c) 5 m (d) -5 m 24. A convergent beam of light passes through a diverging lens of focal length 0.2 m and comes to focus 0.3 m behind the lens. The position of the point at which the beam would converge in the absence of the lens is : (a) 0.12 m (b) 0.6 m (c) 0.3 m (d) 0.15 m 25. In the given figure. The radius of curvature of curved surface for both the plano-convex and plano- concave lens is 10 cm and refractive index for both is 1.5. The location of the final image after all the refractions through lenses is : (a) 15 cm (b) 20 cm (c) 25 cm (d) 40 cm 26. Two lenses of power +10D and -5 D are placed in contact. Where should an object be held from the lens, so as to obtain a virtual image of magnification 2? (a) 5 cm (b) -5 m (c) 10 cm (d) -10 cm 27. A convex refracting surface of radius of curvature 20 cm separates two media of refractive indices 4/3 and 1.60. An object is placed in the first medium (  = 4/ 3 ) at a distance of 200 cm from the refraction surface. The position of the image formed is : (a) 120 cm (b) 240 cm (c) 100 cm (d) 60 cm 28. A double convex lens made of glass of refractive index 1.56 has both radii of curvature of magnitude 20 cm. If an object is placed at a distance of 10 cm from this lens. The position of the image formed is: (a) 22.86 same side of the object (b) 22.86 opposite side of the object (c) 44.89 same side of the object (d) 44.89 opposite side of the object 29. The far point of a near sighted person is 6.0 m from her eyes, and she wears contacts that enable her to see distant objects clearly. A tree is 18.0 m away 2.0 m high. How high is the image formed by the contacts? (a) 0.1 m (b) 1.5 m (c) 0.75 m (d) 0.50 m
30. An eye specialist prescribes spectacles having a combination of a convex lens of focal length 40 Cm in contact with a concave lens of focal length 25 cm. The power of this lens combination is: (a) +1.5 D (b) -1.5 D (c) +6.67D (d) -6.67D 31. The distance of distinct vision of a person is 50 cm. He wants to read a book placed at 25 cm. What should be the focal length of the spectacles? (a) 25 cm (b) 50 cm (c) 75 cm (d) 100 cm 32. A man is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. the diameter of the sun is 1.39 10 m 9  and its mean distance from the earth is 11 1.510 m, the diameter of the sun’s image on the paper is : (a) 3.1 10 m −4  (b) 6.5 10 m −5  (c) 6.5 10 m −4  (d) 9.2 10 m −4  33. A square card of side length 1 mm is being seen through a magnifying lens of focal length of focal length 10 cm. The card is placed at a distance of 9cm from the lens. The card is placed at a distance of 9 cm from the lens. The apparent area of the card through the lens is : (a) 2 1cm (b) 2 0.81cm (c) 2 0.27cm (d) 2 0.60cm 34. The power of a biconvex lens is 10 dioptre and the radius of curvature of each surface is 10 Cm. Then the refractive index of the material of the lens is : (a) 2 3 (b) 3 4 (c) 8 9 (d) 3 5 35. Double convex lenses are to be manufactured form a glass of refractive index 1.55, With both faces of same radius of curvature. What is the radius of curvature required it the focal length is : (a) 11 cm (b) 22 cm (c) 7 cm (d) 6 cm 36. A convex of lens of focal length 15 cm is placed on a plane mirror. An object is placed at 30 cm from the lens. The image is : (a) Real, at 30 cm in front of the mirror (b) Real, at 30 cm behind the mirror (c) Real, at 10 cm in front of the mirror (d) Virtual ,at 10 cm behind the mirror 37. A thin glass (refractive index 1.5) lens has optical power of -8 Din air. Its optical power in a liquid medium with refractive index 1.6 will: (a) 1 D (b) -1 D (c) 25 D (d) -25D 38. A plano-convex (  = 20cm ) is silvered at plane surface. The focal length will be : (a) 20 cm (b) 40 cm (c) 30 cm (d) 10 cm 39. A cancave lens is placed in contact with a convex lens of focal length 25 cm. The combinations produces a real image at a distance of 80cm, if an object is at a distance of 40 cm, the focal length of concave lens is: (a) -400 cm (b) -200 cm (c) +400 cm (d) +200 cm 40. What is the refractive index of material of a plano – convex lens, if the radius of curvature of the convex surface is 10 cm and focal length of the lens is 30 cm? (a) 7 6 (b) 4 7 (c) 3 2 (d) 3 4 41. Two identical glass 2 3 g = equiconvex lenses of focal length F are kept in contact. The space between the two lenes is filled with water        = 3 4 w .The focal length of the combination is : (a) f (b) 2 f (c) 3 4f (d) 4 3f 42. The radii of curvature of the surface of double convex lens are 20 cm and 40 cm respectively, and its focal length is 20 cm. What is the refractive index of the material of the lens? (a) 2 5 (b) 3 4 (c) 3 5 (d) 5 4 43. A real image of a distant object is formed by a planoconvex lens on its principle axis. Spherical aberration is : (a) Absent (b) Smaller, if the curved surface of the lens face the object. (c) Smaller, if the plane surface of the lens faces the object. (d) Same, whichever side of the lens faces the object. 44. A converging lens is used to from an image on a screen. When the upper half of the lens is covered by an opaque screen, (a) Half the image will disappear (b) Complete image will disappear (c) Intensity of image will decrease (d) Intensity of image will increase 45. Which of the following forms a virtual and erect image for all positions of the object? (a) Concave lens (b) Concave mirror (c) Convex mirror (d) Both (b) and(c) 46. A convex lens of radii of curvature 20 cm and 30 cm respectively. It is silvered at the surface which has smaller radius of curvature. Then if will behave as ( g =1.5 ): (a) Concave mirror with equivalent focal length 11 30 cm (b) Concave mirror with equivalent focal length 11 60 cm (c) Concave mirror with equivalent focal length 11 30 cm.
(d) Concave mirror with equivalent focal length 11 60 cm. 47. A mark placed on the surface of a sphere is viewed through glass from a position directly opposite. If the diameter of the sphere is 10 cm and refractive index of glass is 1.5. The position of the image will be: (a) -20 cm (b) 30 cm (c) 40 cm (d) -10 cm 48. Two lenses of focal length 20 cm and -40 cm are held in contact. The image of an object at infinity will be formed by the combination at : (a) 10 cm (b) 20 cm (c) 40 cm (d) Infinity 49. An object is placed at a distance of 1.5m from a screen and a convex lens is interposed between them. The magnification produced. Is 4 The focal length of lens is ; (a) 1 cm (b) 0.5 cm (c) 0.24 cm (d) 2 cm 50. The radius of curvature of each surface of a convex lens of refractive index 1.5 is 40cm. Its power is: (a) 2.5 D (b) 2 D (c) 1.5 D (d) 1 D 51. The image of the needle placed 45 cm from a lens is formed on the other side of the lens. The displacement of the image, if the needle is moved by 5.0 cm away from the lens is (a) 10 cm, toward the lens (b) 15 cm, toward the lens (c) 15 cm, toward the lens (d) 10 cm, toward the lens 52. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will: (a) Become zero (b) Become infinite (c) Become small, but non-zero (d) Remain uncharged 53. A concave mirror of focal length 1 f is placed at a distance of d from a convex lens of focal length 2. f .A beam of light coming from infinity and falling on this convex lens- concave mirror combination returns to infinity. The distance d must equal (a) 1 2 f + f (b) 1 2 − f + f (c) 1 2 2f + f (d) 1 2 − 2f + f 54. The angle of minimum deviation from prism of angle / 3 is / 6 ,if the velocity of light in vacuum is 3 10 ms , 8 −1  then the velocity of light in material of the prism is : (a) 8 1 2.12 10 ms−  (b) 8 1 1.12 10 ms−  (c) 8 1 4.12 10 ms−  (d) 8 1 5.12 10 ms−  55. Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 600 ).In the position of minimum deviation, the angle of refraction will be: (a) 300 for both the colors (b) Greater for the violet color (c) Greater for the red color (d) Equal but not 300 for both the colors 56. A small angle prism (  =1.62)gives a deviation of 4.80 . The angle of prim is : (a) 50 (b) 6.360 (c) 30 (d) 7.740 57. For a glass prism (  = 3 ) the angle of minimum deviation is equal to the angle of the prism. The angle of the prism is : (a) 450 (b) 300 (c) 900 (d) 600 58. A ray of light passes through an equilateral prism (refractive index 1.5) such that angle of incidence is equal to angle of emergence and the latter is equal to 3/4th of the angle of prism. The angle of deviation is : (a) 600 (b) 300 (c) 450 (d) 1200 59. A ray of light is incident at 600 on one face of a prism of angle 300 and the emergent ray makes 300 with the incident ray. The refractive index of the prism is : (a) 1.732 (b) 1.414 (c) 1.5 (d) 1.33 60. A ray incident at an angle of incidence I on one surface of a prism of small angle A and emerges normally from opposite surface. If the refractive index of the material opposite surface. If the refractive index of the material of prism is  , the angle of incidence I is nearly equal to: (a)  A (b) 2 A (c) A (d) 2 A 61. Which of the following colours of white light deviated most when passes through a prism? (a) Red light (b) Violet light (c) Yellow light (d) Both (a) and (b) 62. When light ray undergoes two internal reflection inside a raindrop, which of the rainbow is formed? (a) Primary rainbow (b) Secondary rainbow (c) Both (a) and (b) (d) Can’t say 63. Which of the following statement is correct? (a) At sunset of sunrise, the sun’s rays have to pass through a small distance in the atmosphere. (b) At sunset or sunrise the sun’s rays have to pass through a larger distance in the atmosphere. (c) Rayleigh scattering which is proportional to (d) Most of the blue and other shorter wavelength are not removed by scattering. 64. A compound microscope consists of an objective lens with focal length 1.0 cm and eye piece of focal length 2.0 cm and a tube length 20 cm the magnification will be : (a) 100 (b) 200 (c) 250 (d) 300 65. The focal length of the lenses of an astronomical telescope are 50 cm and 5 cm. The length of the telescope when the image is formed at the least distance of distinct vision is : (a) 45 cm (b) 55 cm (c) cm 6 275 (d) cm 6 325 66. A reflecting telescope has a large mirror for its objective with radius of curvature equal to 80 cm. The magnifying power of this telescope if eye piece used has a focal length of 1.6 cm is (a) 100 (b) 50 (c) 25 (d) 5