EXPERIMENT NO. – 2

SECTION – A

(0.5 MARK) 1. During the passage of ray of light from one medium to another, the ray (a) changes its path (b) follows the same path (c) laterally displaced (d) none of these 2. When the rays travel from one medium to another, it changes its path. It is due to: (a) change in frequency (b) change in speed of light (c) change in wavelength (d) all of these 3. When light travels from air to glass, it bends (a) away from normal (b) parallel to air-glass interface (c) towards normal (d) retrace its path 4. The amount by which a ray of light bends when it enters the glass from air, depends on the (a) frequency of light in glass (b) speed of light in air (c) wavelength of light in air (d) speed of light in glass 5. Which of the following figure shows the traveling of light from rarer (R) to denser (D) medium? (a) Figure (I) and (IV) only (b) Figure (II) and (III) only (c) Figure (III) only (d) Figure (I) only 6. A student tracing the path of ray passing through the rectangular glass-slab. He/she should fix the pins on the board (a) vertically (b) not be hammered (c) proper alignment of the feet of a pin (d) all of these 7. The emergent ray from the glass slab and incident ray are (a) parallel to each other (b) perpendicular (c) laterally displaced (d) both (a) and (c) 8. The ratio of the sine of incident angle to the since of refracted angle is called (a) Snell’s law (b) refractive index (c) both (a) and (b) (d) neither (a) nor (b) 9. For a given pair of air-glass interface, a student increases the angle of incidence, he found refracting angle will (a) decrease (b) increase

(c) remain the same (d) first decrease then increase 10. n21 is called (a) refractive index of 2nd medium with respect to 1st medium (b) refractive index of the 1st medium with respect to 2nd medium (c) absolute refractive index of 2nd medium (d) absolute refractive index of 1st medium 11. A student, while tracing the path of ray of light, passing through the glass-slab, fix two pins vertically on a inclined straight line and look the images of these pins from the other side and fix two other pins such that (a) his eye and feet of the pins are in a straight line (b) his eye and head of pins are in a straight line (c) his eye and middle point of pins are in a straight line (d) his eye and feet of all pins are in different line 12. A student tries to plot a graph between sin i and sin r. Which of the following represents correct graph? (a) Figure (III) only (b) Figure (II) only (c) Figure (I) only (d) None of these 13. When the incident ray falls normally on the glass slab. The emergent ray will be: (a) parallel to the incident ray (b) deviates at an angle of 30o

(c) goes straight through the glass slab (d) angle of refraction is greater than the incident angle 14. A ray of light traveling in water emerges into air. It will bend (a) towards normal (b) away from normal (c) go straight (d) parallel and laterally displaced 15. Refraction is caused by the change in (a) speed of light (b) refractive index of the medium (c) frequency (d) All of these 16. When the ray of light is going from rarer to denser medium, the incident and refraction angles are related as (a)i=r (b)i>r (c)i<r (d)i £ r 17. When the ray of light is going from denser to rarer medium, the angle of refraction is always (a) smaller than the angle of incident (b) equal to the angle of incidence (c) greater than the angle of incidence (d) all of these 18. In a parallel face glass slab, the refraction occurs (a) at one side only (b) at both the parallel opposite sides (c) twice but from the adjacent sides (d) all the four sides 19. The incident ray and emergent ray are parallel to each other because the refraction takes place from the faces of glass slab which are only (a) parallel (b) perpendicular (c) both (a) and (b) (d) neither (a) nor (b) 20. The speed of light in glass is (a) equal as in air (b) greater than the speed in air (c) equal to the speed of sound (d) less than the speed of light in air 21. The relation between emergent angle and angle of incidence is (a)e=i (b)e>i (c)e<i (d)e=2i 22. A medium in which light travels faster is called (a) optically denser medium (b) optically rarer medium (c) less denser medium (d) none of the above 23. When light travels from glass to water, its speed (a) increases (b) decreases (c) remains the same (d) none of these 24. Refraction of light takes place only when light goes from

(a) optically rarer medium to an optically denser medium (b) optically denser to optically rarer medium (c) both (a) and (b) (d) neither (a) nor (b) 25. In the glass slab experiment, four students A, B, C and D did the following: A : kept the eyes far from the glass slab while placing both the pins P3 and P4. B : kept the eyes close to the glass slab while placing both the pink P3 and P4. C : kept the eyes close to the glass slab while placing pin P3 and far from the slab while placing pin P4. D : kept the eyes far from the glass slab while placing pin P3 and close to the slab while placing pin P4. The correct procedure is that of student:

(a)A (b)B (c)C (d)D 26. In the experiment to trace the path of a ray of light through a rectangular glass slab using pins P1, P2, P3 and P4, four students did the following: A : looked at heads of P1 and P2 while placing P3, and heads of P1, P2 and P3 while placing P4. B : looked at feet of P1 and P2 while placing P3, and feet of P1, P2 and P3 while placing P4. C : looked at heads of P1 and P2 while placing P3, and feet of all the pins while placing P4. D : looked at feet of P1 and P2 while placing P3, and heads of all the pins while placing P4. The correct procedure is that of student:

(a)A (b)B (c)C (d)D 27. In an experiment to trace the path of a ray of light passing through a rectangular glass slab, the correct measurement of angles of incidence (i), refraction (r) and emergence (e) is shown in diagram: (a)A (b)B (c)C (d)D 28. At the point of emergence, angle of emergence measured with respect to (a) normal drawn at the point of emergence (b) edge of the glass slab (c) perpendicular edge of glass slab (d) direction of incident ray 29. Lateral displacement produced by the refracted ray

is directly proportional to (a) angle of incidence (b) angle of refraction (c) angle of reflection (d) thickness of glass slab 30. Which of the following figures shows correct labeling of angles where symbols have their usual meanings?

(a) Fig. (i) and (ii) only (b) Fig. (ii) and (ii) only (c) Fig. (iii) only (d) Fig. (iv) only 31. The unit of refractive index is: (a) m/s (b) km/h (c) m/s2 (d) It has no unit (1 MARK)

SECTION – B

32. In passing through a glass plane obliquely, a ray of light (a) neither converges nor diverges (b) is displaced parallel to itself (c) moves in the same direction (d) both (a) and (b) 33. A rectangular glass-slab is made of two transparent media b and c bounded by a parallel face. A ray of light incident on a air – b interface, then: (a) anb ´ bnc=1 (b) anb ´ bnc ´ can = 1 (c) bnc ´ anb = can (d) none of these 34. When the light goes from one medium to another medium, which of the following does not change? (a) wavelength (b) speed (c) intensity (d) frequency 35. For the same angle of incidence, the angle of refraction in medium A, B and C are 45o, 35o, 20o respectively. The velocity of light will be minimum in the medium (a)A (b)B (c) C (d) both (a) and (b) 36. A student traces the path of ray of light passing through glass slab. He performs the experiment first by using blue colour pins and then repeats the experiment with red colour pins for the same angle of incidence. He compares the angle of refraction at the air-glass interface of both the observations. Which relation he would find to be true? (a)rR>rv (b)rR<rv (c)rR=rv (d)rR=rv=i 37. When light travels from an optically rarer medium to an optically denser medium, the velocity of light decreases because of change in (a) frequency (b) amplitude (c) wavelength (d) time period 38. If a glass rod is immersed in a liquid of the same refractive index, then it will (a) appear to be longer (b) appear to be shorter (c) glass rod will disappear (d) none of these 39. A beam of light composed of red and green rays is incident obliquely at a point on the face of a rectangular glass-slab. When coming out from the opposite parallel face, the red and green colours emerge from

(a) one point propagating in two different directions (b) one point propagating in the same direction (c) two points propagating in two different parallel directions (d) two points propagating in same direction 40. Out of the four set-ups shown for carrying out the experiment to trace the path of a ray of light through a rectangular glass slab, the best set up is: (a)A (b)B (c)C (d)D 41. Four students showed the following traces of the path of a ray of light passing through a rectangular glass slab. The trace most likely to be correct is that of student:

(a)A(b)B

(c)C (d)D 42. In an experiment to trace the path of a ray of light passing through a rectangular glass slab, four students tabulated their observations as given below. S. No. Aangle of incidence (degree) Angle of refraction (degree) Angle of emergence (degree) A 1 2 3 30 45 60 18 28 35 32 43 60 B 1 2 3 30 45 60 15 20 28 38 53 67 C 1 2 3 30 45 60 10 15 22 31 44 60 D

1 2 3 30 45 60 28 40 56 28 40 60

The student most likely to have done the experiment property is:

(a)A (b)B (c)C (d)D 43. Difference between the angle of emergence and angle of incidence is: (a) 180o (b) 90o (c) 0o (d) 30o 44. Teacher advises the student, that he should take the angle of incidence not more than 60o. This is because for higher angle of incidence, the emergent ray (a) moves along the same path (b) tends to graze along the slab (c) tends to move along the normal (d) none of these 45. In an experiment to trace the path of a ray of light passing through a rectangular glass slab, student must take the precaution/s (a) Range of incident angle should be 300 – 60o (b) The eye must be in line with the feet of pins (c) The alpines used must have sharp point and stand vertically on the board (d) All the three 46. A student tries to trace the path of light with the glass slab whose two opposite faces are not parallel with each other. He observe (a) Emergent ray is not parallel to incident ray (b) Emergent ray is parallel to incident ray (c) Emergent angle depends upon the refractive index of the medium (d) Both (a) and (c) only 47. Which of the following phenomena is produced by refraction of light? (a) A pencil partly immersed in water appears bent. (b) The bottom of water tank appears to be raised. (c) A coin is placed at bottom of water tank appears to be raised

(d) All of these 48. In the given figure MN represents the lateral displacement of a ray of light emerging out from a rectangular glass slab of thickness AB. If the thickness of the glass slab is increased to AC, the lateral displacement will be: (a) remains the same (b) less than MN (c) more than MN (d) zero as the ray emerges out

ANSWERS

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a b c d c d d c b . a

11. a 12. c 13. c 14. b 15. a 16. b 17. c 18. b 19. a 20. d 21. a 22. b 23. a 24. c 25. a 26. b 27. a 28. a 29. d 30. c 31. d 32. d 33. b 34. d 35. c 36. a 37. c 38. c 39. b 40. b 41. b 42. a

43. c 44. b 45. d 46. d 47. d 48. c