This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Physics Part Ii > Class 12 Physics (Part Ii) Chapter 9 Ray Optics And Optical Instruments – Quiz 2 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part Ii) Chapter 9 Ray Optics And Optical Instruments Quiz 2 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the wavelength range of light as defined in the text? A) 200 nm to 400 nm. B) 100 nm to 400 nm. C) 400 nm to 750 nm. D) 750 nm to 1000 nm. Show Answer Correct Answer: C) 400 nm to 750 nm. 2. The power of a thin convex lens of glass is 5 D. When it is immersed in a liquid, then it behaves like a divergent lens of focal length 100 cm. The refractive index of the liquid is:(Given, refractive index of glass = $\mu$ = 1.5) A) 5/3. B) 2/3. C) 3/5. D) 1/2. Show Answer Correct Answer: A) 5/3. 3. If two mirrors are inclined at some angle an object is placed between the mirrors and there are seven images formed for an object. Then, what is an angle between the mirrors? A) 54$^\circ$. B) 50$^\circ$. C) All the above. D) None of the above. Show Answer Correct Answer: A) 54$^\circ$. 4. A lens behaves as a converging lens in air and as a diverging lens in water. The refractive index of the material is: A) Equal to unity. B) Equal to 1.33. C) Between unity and 1.33. D) Greater than 1.33. Show Answer Correct Answer: C) Between unity and 1.33. 5. What is the critical angle for glass? A) 60$^\circ$. B) 24$^\circ$. C) 48$^\circ$. D) 42$^\circ$. Show Answer Correct Answer: D) 42$^\circ$. 6. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Which one of the following is not possible? A) The length of the telescope tube is 20.02 m. B) The magnification is 1000. C) The image formed is inverted. D) An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image. Show Answer Correct Answer: D) An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image. 7. A Thin lens of focal length f and its aperture has diameter d. it forms an image of intensity 3. Now the central part of aperture upto diameter d/2 is blocked by an opaque paper. The focal length and image intensity would change to A) F, 1/4. B) 3f/4, 1/2. C) F/2, 1/2. D) F, 3/4. Show Answer Correct Answer: A) F, 1/4. 8. What is the main purpose of a telescope? A) To focus light. B) To magnify distant objects. C) To reflect light. D) To magnify nearby objects. Show Answer Correct Answer: B) To magnify distant objects. 9. What is the formula for the lens maker's equation? A) 1/f = R1 + R2. B) 1/f = $\mu$(1/R1 + 1/R2). C) 1/f = ($\mu$ + 1)(1/R1 + 1/R2). D) 1/f = ($\mu$-1)(1/R1-1/R2). Show Answer Correct Answer: D) 1/f = ($\mu$-1)(1/R1-1/R2). 10. A passenger in an aeroplane shall A) Never see a rainbow. B) May see a primary and a secondary rainbow as concentric circles. C) May see a primary and a secondary rainbow as concentric arcs. D) Shall never see a secondary rainbow. Show Answer Correct Answer: B) May see a primary and a secondary rainbow as concentric circles. 11. What is the main reason for the brilliance of diamonds? A) High refractive index. B) High mass. C) Low density. D) Total internal reflection. Show Answer Correct Answer: D) Total internal reflection. 12. Two lenses of focal lengths 20 cm and-40 cm are held in contact. If an object lies at infinity, image formed by the lens combination will be a A) 20cm. B) Infinity. C) 40cm. D) 60cm. Show Answer Correct Answer: A) 20cm. 13. When a thin convex lens is put in contact with a thin concave lens of the same focal length, the resultant combination had focal length equal to: A) 2f. B) Zero. C) Infinity. D) F/2. Show Answer Correct Answer: C) Infinity. 14. What is the term for the distance between two nearby objects that can be resolved by an optical instrument? A) Magnification. B) Limit of resolution. C) Aperture. D) Focal length. Show Answer Correct Answer: B) Limit of resolution. 15. A convex mirror has a focal length f. A real object is placed at a distance f in front of it, from the pole. It produces an image at A) 2f. B) Infinity. C) F. D) F/2. Show Answer Correct Answer: B) Infinity. 16. The radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3m & the refractive index of material is 1.5 is A) 1.25m. B) 0.15m. C) 1.5m. D) 0.5m. Show Answer Correct Answer: D) 0.5m. 17. The focal length of a biconvex lens of radii of each surface 50 cm and refractive index 1.5, is A) 50 cm. B) 40.4 cm. C) 80 cm. D) 75 cm. Show Answer Correct Answer: A) 50 cm. 18. What is the effect of increasing the radius of curvature of a lens on its focal length? A) Focal length decreases. B) Focal length becomes negative. C) Focal length increases. D) Focal length remains the same. Show Answer Correct Answer: C) Focal length increases. 19. Refractive index of water is 5/3. A light source is placed in water at a depth of 4 m. Then what must be the maximum radius of disc placed on water surface so that the light of source can be stopped? A) 5 m. B) 3 m. C) Infinity. D) 4 m. Show Answer Correct Answer: C) Infinity. 20. The magnifying power of an astronomical telescope in normal adjustment is 100. The distance between the objective and the eyepiece is 101 cm. The focal length of the objectives and eyepiece is A) 10 cm and 1 cm respectively. B) 100 cm and 1 cm respectively. C) 1 cm and 100 cm respectively. D) 1 cm and 10 cm respectively. Show Answer Correct Answer: B) 100 cm and 1 cm respectively. 21. Optical fibres use the phenomenon of: A) Polarisation. B) Interference. C) Total internal reflection. D) Refraction. Show Answer Correct Answer: C) Total internal reflection. 22. What is the primary purpose of using optical fibers? A) To bend light. B) To transmit light signals with minimal loss. C) To magnify images. D) To reflect light. Show Answer Correct Answer: B) To transmit light signals with minimal loss. 23. What is the refractive index of water as mentioned in the text? A) 1.00. B) 1.25. C) 1.50. D) 1.33. Show Answer Correct Answer: D) 1.33. 24. A convergent double of separated lens, corrected for spherical aberration, are separated by 2 m and has an equivalent focal length of 10 cm. Calculate the focal length of its component lenses. A) F1=20 cm, f2=28 cm. B) F1=20 cm, f2=18 cm. C) F1=24 cm, f2=18 cm. D) F1=18 cm, f2=10 cm. Show Answer Correct Answer: D) F1=18 cm, f2=10 cm. 25. A glass lens is immersed in water. Its power will A) Decrease. B) Increase. C) Remains same. D) None of the above. Show Answer Correct Answer: A) Decrease. 26. Total internal reflection occurs when A) Light travels from a denser to rarer medium. B) Light travels from a denser to rarer medium, and the angle of incidence is less than the critical angle. C) Light travels from a rarer to denser medium, and the angle of reflection is less than the critical angle. D) Light travels from a denser to rarer medium, and the angle of incidence is greater than the critical angle. Show Answer Correct Answer: D) Light travels from a denser to rarer medium, and the angle of incidence is greater than the critical angle. 27. In the minimum deviation position, the refracted ray in the prism is A) Parallel to the base of prism. B) Perpendicular to the base of prism. C) Parallel to the any side of prism. D) None of the above. Show Answer Correct Answer: A) Parallel to the base of prism. 28. The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it wil A) Act as a concave lens for the objects that lie on its curved side. B) Act as a concave lens irrespective of side on which the object lies. C) Act as a convex lens only for the objects that lie on its curvedside. D) Act as a convex lens irrespective of the side on which the objectlies. Show Answer Correct Answer: D) Act as a convex lens irrespective of the side on which the objectlies. 29. An equilateral prism deviates a ray through 45$^\circ$ for the two angle of incidence differing by 20$^\circ$. The angle of incidence is A) 60$^\circ$. B) 40$^\circ$. C) 120$^\circ$. D) None of these. Show Answer Correct Answer: A) 60$^\circ$. 30. Focal length of the objective and eyepiece of a telescope are respectively 50 cm and 5 cm. The magnifying power of the telescope in its normal adjustment is A) 0.1. B) 10. C) 1.1. D) 11. Show Answer Correct Answer: B) 10. 31. At the minimum deviation of condition in a prism A) The refracted ray is parallel to the base of the prism. B) The incident angle is equal to the angle of emergence. C) Angle of refraction is half of the angle of prism. D) All of the above. Show Answer Correct Answer: D) All of the above. 32. An object 2.4m in front of a lens form a sharp image on a film 12 cm behind the lens. A glass plate 1 cm thick, of refractive index 1.50 is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object shifted to be in sharp focus on film? A) 2.4m. B) 3.2m. C) 5.6m. D) 7.2m. Show Answer Correct Answer: D) 7.2m. 33. A rectangular block of glass ABCD has a refractive index 1.6.A pin is placed midway on the face AB (Fig. 9.4). When observed from the face AD, the pin shall A) Appear to be near A. B) Appear to be near D. C) Appear to be at the centre of AD. D) Not be seen at all. Show Answer Correct Answer: D) Not be seen at all. 34. What phenomenon occurs when light travels from a denser medium to a rarer medium at an angle greater than the critical angle? A) Reflection. B) Total Internal Reflection. C) Refraction. D) Dispersion. Show Answer Correct Answer: B) Total Internal Reflection. 35. 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 unchanged. Show Answer Correct Answer: B) Become infinite. 36. Objects are visible in light due to: A) Absorption. B) Scattering. C) Fluorescence. D) Refraction. Show Answer Correct Answer: B) Scattering. 37. Digital movie projectors work on the principle of A) Reflection from micromirrors. B) Refraction from thin lenses. C) Total internal reflection from optical fibres. D) Dispersion from thin prisms. Show Answer Correct Answer: A) Reflection from micromirrors. 38. Two convex lenses are separated by a distance equal to the sum of their focal lengths. A beam of light parallel to the principal axis incidence on one of the lenses. They will emerge from the second lens as A) A beam of parallel rays. B) As a beam of diverging rays. C) As a beam of converging ray. D) None of the above. Show Answer Correct Answer: A) A beam of parallel rays. 39. What is the power of a lens with a focal length of 0.5 m? A) 0.5 D. B) 4 D. C) 1 D. D) 2 D. Show Answer Correct Answer: D) 2 D. 40. In a simple microscope, if the focal length of the convex lens is 5 cm, what is the maximum magnification achievable? A) 15. B) 20. C) 5. D) 10. Show Answer Correct Answer: D) 10. 41. A man runs towards a mirror at a rate of 6 m/s if we assume the mirror to be at rest, the image will have velocity- A) +12 m/s. B) -12 m/s. C) -6 m/s. D) +6 m/s. Show Answer Correct Answer: A) +12 m/s. 42. A convex lens and a concave lens, each having the same focal length of 25 cm, are put in contact to form a combination of lenses. The power of the combination (in dioptres) is A) 50. B) Infinity. C) 25. D) Zero. Show Answer Correct Answer: D) Zero. 43. A compound microscope has an eyepiece of focal length 10 cm and an objective of focal length 4 cm. Calculate the magnification if an object is kept at a distance of 5 cm from the objective, then the final image is formed at the least distance of distinct vision. A) 11. B) 13. C) 12. D) 10. Show Answer Correct Answer: A) 11. 44. What is the effect of increasing the angle of incidence on the angle of refraction? A) It becomes zero. B) It remains constant. C) It increases. D) It decreases. Show Answer Correct Answer: C) It increases. 45. A convergent lens made of crown glass has focal length 20cm in air. If it is immersed in a liquid of refractive index 1.60, its focal length will be A) 80 cm. B) -80 cm. C) 160 cm. D) -160 cm. Show Answer Correct Answer: D) -160 cm. 46. A thin prism of 12$^\circ$ angle gives a deviation of 6$^\circ$. The refracting index of a material of the prism A) 1.5. B) 1.2. C) 1.7. D) 1.6. Show Answer Correct Answer: A) 1.5. 47. What is the refractive index of water? A) 1.50. B) 1.25. C) 1.33. D) 1.00. Show Answer Correct Answer: C) 1.33. 48. The shortest height of a vertical mirror required to see the entire image of a man will be A) Data insufficient. B) Half the man's height. C) Two third of the man's height. D) One third of the man's height. Show Answer Correct Answer: B) Half the man's height. 49. Find the change in the focal length of the lens, if a convex lens of focal length 20 cm and refractive index 1.5, is emerged in water having refractive index 1.33. A) 6.22 cm. B) 58.2 cm. C) 5.82 cm. D) 62.2 cm. Show Answer Correct Answer: D) 62.2 cm. 50. The magnifying power of an astronomical telescope can be increased if we: A) Increase the focal length of the objective. B) Increase the focal length of the eye piece. C) Decrease the focal length of the objective. D) Decrease the focal length of the objective and at the same time increase the focal length of the eye piece. Show Answer Correct Answer: D) Decrease the focal length of the objective and at the same time increase the focal length of the eye piece. 51. What is the primary function of the ciliary muscles in the human eye? A) Change the shape of the lens. B) Control pupil size. C) Regulate light entry. D) Focus on distant objects. Show Answer Correct Answer: A) Change the shape of the lens. 52. Tara is experimenting with a glass prism in her science lab. She shines a beam of light through the prism and observes the different colors that emerge. She notices that the angle of deviation for the colors varies. Which color does she find has the greatest angle of deviation? A) Orange. B) Violet. C) Red. D) Yellow. Show Answer Correct Answer: B) Violet. 53. What is the focal length of a plane mirror? A) Positive. B) Infinity. C) Zero. D) Negative. Show Answer Correct Answer: B) Infinity. 54. The direction of ray of light incident on a concave mirror is shown by PQ while directions in which the ray would travel after reflection is shown by four rays marked 1, 2, 3 and 4(Fig 9.1). Which of the four rays correctly shows the direction of reflected ray? A) 3. B) 1. C) 2. D) 4. Show Answer Correct Answer: C) 2. 55. What is the relationship between the focal length (f) and the radius of curvature (R) of a concave mirror? A) F = 2R. B) F = R. C) F = R/2. D) F = R/3. Show Answer Correct Answer: C) F = R/2. 56. What type of optical instrument uses two lenses to observe distant celestial objects? A) Simple Microscope. B) Camera. C) Astronomical Telescope. D) Compound Microscope. Show Answer Correct Answer: C) Astronomical Telescope. 57. What is the term for the splitting of white light into its constituent colors? A) Refraction. B) Dispersion. C) Scattering. D) Reflection. Show Answer Correct Answer: B) Dispersion. 58. What is the relationship between the object distance (u), image distance (v), and focal length (f) for a lens? A) 1/f = 1/u-1/v. B) 1/v = 1/f + 1/u. C) 1/v + 1/u = 1/f. D) 1/f = 1/v + 1/u. Show Answer Correct Answer: D) 1/f = 1/v + 1/u. 59. What is the phenomenon of light bending as it passes from one medium to another called? A) Reflection. B) Diffraction. C) Dispersion. D) Refraction. Show Answer Correct Answer: D) Refraction. 60. The phenomena involved in the reflection of radiowaves byionosphere is similar to A) Reflection of light by a plane mirror. B) Total internal reflection of light in air during a mirage. C) Scattering of light by the particles of air. D) Dispersion of light by water molecules during the formation of arainbow. Show Answer Correct Answer: B) Total internal reflection of light in air during a mirage. ← PreviousNext →Related QuizzesScience QuizzesClass 12 QuizzesClass 12 Physics (Part Ii) Chapter 9 Ray Optics And Optical Instruments Quiz 1Class 12 Physics (Part Ii) Chapter 9 Ray Optics And Optical Instruments Quiz 3Class 12 Physics (Part Ii) Chapter 10 Wave Optics QuizClass 12 Physics (Part Ii) Chapter 11 Dual Nature Of Radiation And Matter QuizClass 12 Physics (Part Ii) Chapter 12 Atoms QuizClass 12 Physics (Part Ii) Chapter 13 Nuclei QuizClass 12 Physics (Part Ii) Chapter 14 Semiconductor Electronics Materials Quiz 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books