Tiêu đề 28. Ray Optics Easy 2.pdf ✅

1. A beam of light composed of red and green ray is incident obliquely at a point on the face of rectangular glass slab. When coming out on the opposite parallel face, the red and green ray emerge from (a) Two points propagating in two different directions (b) Two points propagating in two parallel directions (c) One point propagating in two different directions (d) One point propagating in the same directions 2. White light is passed through a prism ........... colour shows minimum deviation (a) Red (b) Violet (c) Yellow (d) Green 3. A ray of monochromatic light suffers minimum deviation of o 38 while passing through a prism of refracting angle o 60 . Refractive index of the prism material is (a) 1.5 (b) 1.3 (c) 0.8 (d) 2.4 4. A ray incident a o 15 on one refracting surface of a prism of angle o 60 , suffers a deviation of o 55 . What is the angle of emergence (a) o 95 (b) o 45 (c) o 30 (d) None of these 5. The spectrum obtained from a sodium vapour lamp is an example of (a) Absorption spectrum (b) Emission spectrum (c) Continuous spectrum (d) Band spectrum 6. The sky would appear red instead of blue if (a) Atmospheric particles scatter blue light more than red light (b) Atmospheric particles scatter all colours equally (c) Atmospheric particles scatter red light more than the blue light (d) The sun was much hotter 7. Sir C.V. Raman was awarded Nobel Prize for his work connected with which of the following phenomenon of radiation (a) Scattering (b) Diffraction (c) Interference (d) Polarisation 8. In absorption spectrum of Na the missing wavelength (s) are (a) 589 nm (b) 589.6 nm (c) Both (d) None of these 9. A far sighted man who has lost his spectacles, reads a book by looking through a small hole (3-4 mm) in a sheet of paper. The reason will be (a) Because the hole produces an image of the letters at a longer distance (b) Because in doing so, the focal length of the eye lens is effectively increased (c) Because in doing so, the focal length of the eye lens is effectively decreased (d) None of these 10. For a normal eye, the least distance of distinct vision is (a) 0.25 m (b) 0.50 m (c) 25 m (d) Infinite 11. For the myopic eye, the defect is cured by (a) Convex lens (b) Concave lens (c) Cylindrical lens (d) Toric lens 12. Substance on the choroid is (a) Japan black (b) Nigrim pigment (c) Carbon black (d) Platinum black 13. Astigmatism (for a human eye) can be removed by using (a) Concave lens (b) Convex lens (c) Cylindrical lens (d) Prismatic lens 14. Circular part in the centre of retina is called (a) Blind spot (b) Yellow spot (c) Red spot (d) None of the above 15. Image formed on the retina is (a) Real and inverted (b) Virtual and erect (c) Real and erect (d) Virtual and inverted 16. If there had been one eye of the man, then (a) Image of the object would have been inverted (b) Visible region would have decreased (c) Image would have not been seen three dimensional (d) (b) and (c) both 17. A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm (a) + 3.0 D (b) + 0.125 D (c) – 3.0 D (d) + 4.0 D 18. How should people wearing spectacles work with a microscope (a) They cannot use the microscope at all (b) They should keep on wearing their spectacles (c) They should take off spectacles (d) (b) and (c) is both way 19. A man who cannot see clearly beyond 5 m wants to see stars clearly. He should use a lens of focal length (a) – 100 m (b) + 5 m (c) – 5 m (d) Very large
20. A man can see only between 75 cm and 200 cm. The power of lens to correct the near point will be (a) + 8/3 D (b) + 3 D (c) – 3 D (d) – 8/3 D 21. Image is formed for the short sighted person at (a) Retina (b) Before retina (c) Behind the retina (d) Image is not formed at all 22. A man can see the object between 15 cm and 30 cm. He uses the lens to see the far objects. Then due to the lens used, the near point will be at (a) 3 10 cm (b) 30 cm (c) 15 cm (d) 3 100 cm 23. The far point of a myopia eye is at 40 cm. For removing this defect, the power of lens required will be (a) 40 D (b) – 4 D (c) – 2.5 D (d) 0.25 D 24. A man suffering from myopia can read a book placed at 10 cm distance. For reading the book at a distance of 60 cm with relaxed vision, focal length of the lens required will be (a) 45 cm (b) – 20 cm (c) – 12 cm (d) 30 cm 25. If the distance of the far point for a myopia patient is doubled, the focal length of the lens required to cure it will become (a) Half (b) Double (c) The same but a convex lens (d) The same but a concave lens 26. A presbyopic patient has near point as 30 cm and far point as 40 cm. The dioptric power for the corrective lens for seeing distant objects is (a) 40 D (b) 4 D (c) – 2.5 D (d) 0.25 D 27. An imaginary line joining the optical centre of the eye lens and the yellow point is called as (a) Principal axis (b) Vision axis (c) Neutral axis (d) Optical axis 28. The light when enters the human eye experiences most of the refraction while passing through (a) Cornea (b) Aqueous humour (c) Vitrous humour (d) Crystalline lens 29. The impact of an image on the retina remains for (a) 0.1 sec (b) 0.5 sec (c) 10 sec (d) 15 sec 30. A person is suffering from myopic defect. He is able to see clear objects placed at 15 cm. What type and of what focal length of lens he should use to see clearly the object placed 60 cm away (a) Concave lens of 20 cm focal length (b) Convex lens of 20 cm focal length (c) Concave lens of 12 cm focal length (d) Convex lens of 12 cm focal length 31. The sensation of vision in the retina is carried to the brain by (a) Ciliary muscles (b) Blind spot (c) Cylindrical lens (d) Optic nerve 32. When the power of eye lens increases, the defect of vision is produced. The defect is known as (a) Shortsightedness (b) Long-sightedness (c) Colorblindness (d) None of the above 33. A man is suffering from colour blindness for green colour. To remove this defect, he should use goggles of (a) Green colour glasses (b) Red colour glasses (c) Smoky colour glasses (d) None of the above 34. In human eye the focussing is done by (a) To and fro movement of eye lens (b) To and fro movement of the retina (c) Change in the convexity of the lens surface (d) Change in the refractive index of the eye fluids 35. A short sighted person can see distinctly only those objects which lie between 10 cm and 100 cm from him. The power of the spectacle lens required to see a distant object is (a) + 0.5 D (b) – 1.0 D (c) – 10 D (d) + 4.0 D 36. A person can see clearly only upto a distance of 25 cm. He wants to read a book placed at a distance of 50 cm. What kind of lens does he require for his spectacles and what must be its power (a) Concave, – 1.0 D (b) Convex, + 1.5 D (c) Concave, – 2.0 D (d) Convex, + 2.0 D 37. The human eye has a lens which has a (a) Soft portion at its centre (b) Hard surface (c) Varying refractive index (d) Constant refractive index
38. A man with defective eyes cannot see distinctly object at the distance more than 60 cm from his eyes. The power of the lens to be used will be (a) + 60 D (b) – 60 D (c) – 1.66 D (d) D 1.66 1 39. A person's near point is 50 cm and his far point is 3 m. Power of the lenses he requires for (i) reading and (ii) for seeing distant stars are (a) – 2 D and 0.33 D (b) 2 D and – 0.33 D (c) – 2 D and 3 D (d) 2 D and – 3 D 40. A person wears glasses of power – 2.5 D. The defect of the eye and the far point of the person without the glasses are respectively (a) Farsightedness, 40 cm (b) Nearsightedness, 40 cm (c) Astigmatism, 40 cm (d) Nearsightedness, 250 cm 41. Myopia is due to (a) Elongation of eye ball (b) Irregular change in focal length (c) Shortening of eye ball (d) Older age 42. A person is suffering from the defect astigmatism. Its main reason is (a) Distance of the eye lens from retina is increased (b) Distance of the eye lens from retina is decreased (c) The cornea is not spherical (d) Power of accommodation of the eye is decreased 43. A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision will be (a) + 2.0 D (b) – 1.0 D (c) + 1.0 D (d) – 0.5 D 44. The resolving limit of healthy eye is about (a) 1 or        60 1 (b) 1 (c) o 1 (d) " 60 1 45. When objects at different distances are seen by the eye, which of the following remains constant (a) The focal length of the eye lens (b) The object distance from the eye lens (c) The radii of curvature of the eye lens (d) The image distance from the eye lens 46. A person wears glasses of power – 2.0 D. The defect of the eye and the far point of the person without the glasses will be (a) Nearsighted, 50 cm (b) Farsighted, 50 cm (c) Nearsighted, 250 cm (d) Astigmatism, 50 cm 47. An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in diopters is (a) + 1.5 (b) – 1.5 (c) + 6.67 (d) – 6.67 48. Match the List I with the List II from the combinations shown (I) Presbiopia (A) Sphero-cylindrical lens (II) Hypermetropia (B) Convex lens of proper power may be used close to the eye (III ) Astigmatism (C) Concave lens of suitable focal length (IV ) Myopia (D) Bifocal lens of suitable focal length (a) I-A; II-C; III-B; IV-D (b) I-B; II-D; III-C; IV-A (c) I-D; II-B; III-A; IV-C (d) I-D; II-A; III-C; IV-B 49. Near and far points of a human eye are (a) 0 and 25 cm (b) 0 and  (c) 25 cm and 100 cm (d) 25 cm and  50. Two parallel pillars are 11 km away from an observer. The minimum distance between the pillars so that they can be seen separately will be (a) 3.2 m (b) 20.8 m (c) 91.5 m (d) 183 m 51. Retina of eye acts like ........ of camera (a) Shutter (b) Film (c) Lens (d) None of these 52. The hyper-metropia is a (a) Short-side defect (b) Long- side defect (c) Bad vision due to old age (d) None of these 53. Amount of light entering into the camera depends upon (a) Focal length of the objective lens (b) Product of focal length and diameter of the objective lens (c) Distance of the object from camera
(d) Aperture setting of the camera 54. A man cannot see clearly the objects beyond a distance of 20 cm from his eyes. To see distant objects clearly he must use which kind of lenses and of what focal length (a) 100 cm convex (b) 100 cm concave (c) 20 cm convex (d) 20 cm concave 55. A person uses spectacles of power +2D. He is suffering from (a) Short sightedness or myopia (b) Long sightedness or hypermetropia (c) Presbyopia (d) Astigmatism 56. To remove myopia (short sightedness) a lens of power 0.66 D is required. The distant point of the eye is approximately (a) 100 cm (b) 150 cm (c) 50 cm (d) 25 cm 57. A person suffering from 'presbyopia' (myopia and hyper metropia both defects) should use (a) A concave lens (b) A convex lens (c) A bifocal lens whose lower portion is convex (d) A bifocal lens whose upper portion is convex 58. A person who can see things most clearly at a distance of 10 cm. Requires spectacles to enable to him to see clearly things at a distance of 30 cm. What should be the focal length of the spectacles (a) 15 cm (Concave) (b) 15 cm (Convex) (c) 10 cm (d) 0 59. Far points of myopic eye is 250 cm, then the focal length of the lens to be used will be (a) – 250 cm (b) – 250/9 cm (c) + 250 cm (d) + 250/9 cm 60. A man can see clearly up to 3 metres. Prescribe a lens for his spectacles so that he can see clearly up to 12 metres (a) – 3/4 D (b) 3 D (c) – 1/4 D (d) – 4 D 61. A satisfactory photographic print is obtained when the exposure time is 10 sec at a distance of 2 m from a 60 cd lamp. The time of exposure required for the same quality print at a distance of 4 m from a 120 cd lamp is (a) 5 sec (b) 10 sec (c) 15 sec (d) 20 sec 62. A person can not see the objects clearly placed at a distance more than 40 cm. He is advised to use a lens of power (a) – 2.5 D (b) + 2.5 D (c) – 6.25 D (d) + 1.5 D 63. A person uses a lens of power + 3D to normalise vision. Near point of hypermetropic eye is (a) 1 m (b) 1.66 m (c) 2 m (d) 0.66 m 64. A defective eye cannot see close objects clearly because their image is formed (a) On the eye lens (b) Between eye lens and retina (c) On the retina (d) Beyond retina 65. Image formed on retina of eye is proportional to (a) Size of object (b) Area of object (c) Size of image Size of object (d) size of object size of image 66. A student can distinctly see the object upto a distance 15 cm. He wants to see the black board at a distance of 3 m. Focal length and power of lens used respectively will be (a) −4.8 cm, −3.3 D (b) −5.8 cm, −4.3 D (c) −7.5 cm, −6.3 D (d) −15.8 cm, −6.3 D 67. A camera objective has an aperture diameter d. If the aperture is reduced to diameter d / 2, the exposure time under identical conditions of light should be made (a) 2 fold (b) 2 fold (c) 2 2 fold (d) 4 fold 68. The light gathering power of a camera lens depends on (a) Its diameter only (b) Ratio of focal length and diameter (c) Product of focal length and diameter (d) Wavelength of light used 69. The exposure time of a camera lens at the 2.8 f setting is 200 1 second. The correct time of exposure at 5.6 f is (a) 0.4 sec (b) 0.02 sec (c) 0.002 sec (d) 0.04 sec 70. Ability of the eye to see objects at all distances is called (a) Binocular vision (b) Myopia (c) Hypermetropia (d) Accommodation 71. 1. 2. F