1. Mechanics
    2. 1. Units, Dimensions and Errors
    2. Vectors and Scalars
    3. Motion in a Straight Line
    4. Projectile Motion
    5. Newton's Laws of Motion
    6. Friction
    7. Work, Energy, Power and Collision
    8. Circular motion
    9. Rotational motion
    10. Simple Harmonic Motion
    11. Gravitation
    12. Elasticity
    13. Surface Tension
    14. Fluid dynamics and Viscosity
    15. Hydrostatics
  2. Heat and Thermodynamics
    3. 16. Thermometry
    17. Thermal expansion
    18. Calorimetry, Change of State and Hygrometry
    19. Gas Laws and Kinetic theory of Gases
    20. Transmission of Heat
    21. Thermodynamics
  3. Sound and Waves
    4. 22. Wave
    23. Superposition of Waves
    24. Stationary/ Standing waves
    25. Doppler's effect and Musical sound
  4. Optics
    5. 26. Reflection of Plane and Curved Mirrors
    27. Refraction at Plane surfaces and Total internal reflection
    28. Refraction through prism and Dispersion of Light
    29. Refraction through Lenses
    30. Chromatic abberation in Lenses, Optical instruments and Human eye
    31. Velocity of Light
    32. Photometry
    33. Wave nature of Light
  5. Electrostatics
    6. 34. Charge and Force
    35. Electric Field and Potential
    36. Capacitance
  6. Electrodynamics
    7. 37. Electric current
    38. Heating Effect of Current
    39. Thermoelectricity
    40. Chemical effect of Current
    41. Meters
  7. Electromagnetism
    8. 42. Properties of Magnets
    43. Magnetic effects of Current
    44. Electromagnetic induction
    45. Alternating current
  8. Modern Physics
    9. 46. Cathode rays, Positive rays and Electrons
    47. Photoelectric effect
    48. X-rays
    49. Atomic structure and Spectrum
    50. Radioactivity
    51. Nuclear physics
    52. Semiconductor and Semiconductor devices
    53. Diode and Triode valves
    54. Logic gates
    55. Relativity and Universe
    56. Particle physics
Optics
28. Refraction through prism and Dispersion of Light
1. What is the angle of incident of prism of angle 60° and which has refractive index √2 for which it gives minimum deviation?

[BP 2013]

  • 60°
  • 45°
  • 90°
  • 30°
2. A small angle prism deviates a narrow beam of light by 1.3°. The refractive index is 1.62 and the angle of prism in degree is:

[MOE 2014]

  • 1.7°
  • 1.8°
  • 1.9°
  • 2.0°
3. Light passing from air to glass at an angle of incidence 60° is deviated to 15°. What is the refractive index?

[MOE 2010]

  • 1.22
  • 1.33
  • 1.50
  • 1.47
4. An equilateral prism having angle 60° has refractive index √2. What is the angle of incident for minimum angle of deviation?

[IE 2012]

  • 75°
  • 90°
  • 45°
  • 60°
5. The angle of deviation produced by a small angle prism of angle A and refractive index μ is equal to:

[KU 2011]

  • A(μ - 1)
  • μ(A - 1)
  • A(μ + 1)
  • μ(A + 1)
6. An achromatic doublet is constructed by lenses of crown glass and flint glass of dispersive powers 0.02 and 0.03. If the focal length of the crown glass is 20 cm, the focal length of the doublet becomes:

[IOM 05]

  • -60 cm
  • -30 cm
  • 12 cm
  • -12 cm
7. In a right-angled isosceles prism, when the light falls from flat face and for total internal reflection to take place in the second face, the minimum refractive index of the prism is:

[IOM 03]

  • 1.34
  • 1.41 (√2)
  • 1.55
  • 1.66
8. The principle of which of the following is based on deviation without dispersion?

[BPKIHS 2000]

  • Chromatic doublet
  • Achromatic doublet
  • Spectrometer
  • Direct vision spectroscope
9. For minimum deviation inside the prism, the angle of emergence should be equal to:

[IOM 1999]

  • angle of prism
  • angle of incidence
  • angle of refraction
  • angle of deviation
10. The power produced by a prism of small angle A:

[BPKIHS 2000]

  • depends on material of prism only
  • depends on A only
  • depends both on material and A
  • depends neither on material nor on A
11. An impure spectrum of Green, Blue, Orange, and Yellow is observed on a screen when light passes through a transparent prism. The refractive index of the prism with respect to the colours will be maximum for:

[MOE Curriculum]

  • Blue
  • Green
  • Orange
  • Yellow
12. To make an achromatic combination, a convex lens of focal length 42 cm having dispersive power 0.14 is placed in contact with a concave lens of dispersive power 0.21. The focal length of the concave lens should be:

[MOE]

  • 14 cm
  • 21 cm
  • 63 cm
  • 42 cm
13. In the sun's spectrum, if blue & green lights are passed through a transparent prism, then deviation of green light will be:

[MOE 2063]

  • equal so that they form achromatic condition
  • greater than that of blue light
  • smaller than that of blue light
  • can't be predicted
14. An object PQ is placed facing the hypotenuse of a 45°-90°-45° glass prism. What is the nature of the image formed? (Refractive index of prism is 1.5)

[MOE 2056]

  • Erect and diminished
  • Erect and same size
  • Inverted and magnified
  • Inverted and same size
15. In a right-angled glass prism, light is normally incident through the smaller face. Then deviation is:

[MOE 2054]

  • 90°
  • 45°
  • 30°
  • 60°
16. Chromatic aberration is due to:

[MOE 2054]

  • Deviation
  • Dispersion
  • Interference
  • Diffraction
17. Angle of deviation when passing through a prism is greatest for light:

[MOE/KU]

  • Red
  • Violet
  • Blue
  • Yellow
18. In an equilateral prism, if angle of incidence equals angle of emergence and the angle of incidence is 3/4 of angle of prism. Then the angle of deviation produced is:

[KU 2010]

  • 60°
  • 90°
  • 120°
  • 30°
19. An achromatic lens forms an image of a white object. The colour of image seen will be:

[Bangladesh 09]

  • Black
  • Green
  • Yellow
  • White
20. A yellow object on a blue background appears as:

[TE-051]

  • White
  • Black
  • Green
  • Red
21. A prism of refracting angle 60° produces a minimum deviation of 30°. Then the angle of incidence is:

[IE-03]

  • 30°
  • 60°
  • 45°
  • 90°
22. A prism can produce a minimum deviation of 8° in a light beam. If three such prisms are combined, the minimum deviation that can be produced in this beam is:

[BPKIHS-95]

  • 24°
  • 8°
  • 16°
  • 32°
23. The cover of a book appears black when seen through a piece of red glass. Then the cover may be of:

[MOE]

  • Red colour
  • White colour
  • Green colour
  • Red or White
24. A red postage stamp is viewed in yellow light. It appears:

[MOE]

  • Light grey
  • Orange
  • Black
  • Green
25. A blue object on a white background when seen through a blue filter will:

[MOE]

  • Appear blue on white background
  • Appear black on a blue background
  • Appear blue on a red background
  • Become invisible
26. A piece of red glass is heated till it glows in dark. The colour of the glowing piece will be:

[MOE]

  • Red
  • Orange
  • Green
  • Violet
27. From two projectors, beams of red light and green light are sent on the same spot of the screen. The screen will look:

[MOE]

  • White
  • Red
  • Green
  • Yellow
28. For which of the following is the dispersive power zero?

[MOE]

  • Lens
  • Prism
  • Glass slab
  • None of the above
29. Dispersion for a medium of wavelength λ is D. Then the dispersion for the wavelength λ/2 will be:

[MOE]

  • D
  • D/2
  • 2D
  • 4D
30. White light is passed through a prism of angle 5°. If the refractive indices for red and blue rays are 1.641 and 1.659, the angle of dispersion between them is:

[MOE]

  • 2°
  • 1°
  • 0.9°
  • 0.09°
31. A thin prism P1 (angle 4°, μ=1.54) is combined with prism P2 (μ=1.72) to produce dispersion without deviation. The angle of P2 is:

[MOE]

  • 5.33°
  • 3.12°
  • 2.58°
  • 4.82°
32. The difference in deviation produced by violet and red rays is 2°. The deviation produced by the mean ray is 48°. The dispersive power and deviations are:

[MOE]

  • 1/24, 47°, 49°
  • 1/24, 48°, 46°
  • 1/4, 50°, 54°
  • 1/27, 52°, 50°
33. White light is passed through a prism of angle 5°. The refractive indices for red and blue rays are 1.64 and 1.66. The angle of dispersion is:

[MOE]

  • 0.10°
  • 0.20°
  • 0.30°
  • 0.40°
34. A glass prism deviates red and blue rays through 10° and 12° respectively. A second prism deviates them through 8° and 10°. The ratio of their dispersive powers is:

[MOE]

  • 1:1
  • 9:11
  • 3:2
  • 5:4
35. Find the angle of a prism (dispersive power 0.021, μ=1.52) to form an achromatic combination with a second prism (angle 4.2°, dispersive power 0.045, μ=1.65):

[MOE]

  • 10.25°
  • 13.25°
  • 11.25°
  • 9.25°
36. A prism (angle 11.25°, dispersive power 0.021, μ=1.52) forms an achromatic combination with a second prism (angle 4.2°, dispersive power 0.045, μ=1.65). The resultant deviation is:

[MOE]

  • 1.62°
  • 3.12°
  • 5.85°
  • 8.58°
37. The difference between angle of minimum deviation for violet and red rays is 2°. If the angle of mean ray is 48°, the dispersive power of the prism material is:

[MOE]

  • 1/48
  • 1/24
  • 0.0416
  • 0.0832
38. A source emits light of wavelengths 4700Å, 5400Å, and 6500Å. The light passes through red glass before being tested by a spectrometer. Which wavelength is absent in the spectrum?

[MOE]

  • 6500Å
  • 5400Å
  • 4700Å
  • All of the above
39. If angle of prism is 60° and angle of minimum deviation is 40°, then the angle of refraction will be:

[MOE]

  • 30°
  • 60°
  • 100°
  • 120°
40. The angle of prism is A and the minimum deviation is (180° - 2A). Then the refractive index of the prism material is:

[MOE 2062]

  • sin(A)
  • cos(2A)
  • tan(A)
  • cot(A/2)
41. The angle of prism is 6° and its refractive index for green light is 1.5. If a green ray passes through it, the deviation will be:

[MOE]

  • 3°
  • 6°
  • 9°
  • 15°
42. A ray of light suffers minimum deviation through an equilateral prism of refractive index √2. The minimum deviation will be:

[MOE]

  • 30°
  • 45°
  • 60°
  • 90°
43. An equilateral prism has refractive index √2. The angle of incidence which gives minimum deviation is:

[MOE]

  • 60°
  • 45°
  • 90°
  • 30°
44. A ray of light is incident at 60° on a prism (angle 30°). The emerging ray makes 30° with the incident ray. The refractive index of the prism is:

[MOE]

  • 1.33
  • 1.41
  • 1.50
  • 1.73
45. A ray passes through an equilateral prism such that the angle of incidence equals the angle of emergence (each 3/4 of the prism angle). The angle of deviation is:

[MOE]

  • 45°
  • 30°
  • 20°
  • 60°
46. A thin prism of glass is placed in air and water successively. If μg = 3/2 and μw = 4/3, the ratio of deviations (air:water) for small angles is:

[MOE]

  • 1:2
  • 4:3
  • 3:4
  • 4:1
47. The angle of a prism is 30°. A ray incident at 60° on one face suffers a deviation of 30°. The angle of emergence is:

[MOE]

  • 30°
  • 60°
  • 90°
  • 0°
48. A ray is incident on a prism (angle 75°, μ=√2) and undergoes critical angle at the second face. The angle of incidence at the first face is:

[MOE]

  • 30°
  • 45°
  • 60°
  • 90°
49. A ray is incident on a small-angle prism (angle A, μ=μ) and emerges normally. The angle of incidence is nearly:

[MOE]

  • A
  • μA
  • A/μ
  • 2μA
50. The angle of prism is 60°. For minimum deviation (refractive index √2), the angle of incidence is:

[MOE]

  • 45°
  • 60°
  • 30°
  • 90°
51. The refracting angle of a small angle prism is A. The relation between δm (minimum deviation) and angle of refraction (r) will be (μ = 1.5):

[MOE]

  • δm = r
  • δm = 1.5r
  • δm = 2r
  • δm = r/2
52. Angle of prism is A and one surface is silvered. Light falls at angle of incidence 2A on the first surface and returns through the same path. The refractive index of the prism is:

[MOE]

  • 2sinA
  • 2cosA
  • cosA
  • tanA
53. What should be the refractive index of an equilateral prism for total internal reflection?

[MOE]

  • μ > 2
  • μ < 2
  • μ > √2
  • μ < √2
54. A ray is incident normally on one face of a right-angled isosceles prism and undergoes total internal reflection. The minimum refractive index is:

[MOE]

  • √2
  • 1.5
  • √3
  • 2
55. A ray is incident normally on the first face of an equilateral prism and undergoes total internal reflection at the second face. The refractive index must be:

[MOE]

  • μ > 2/√3
  • μ < 2/√3
  • μ > √3
  • μ < √3
56. A glass prism (μ=1.5) is immersed in water (μ=4/3). A light beam incident normally on face AB is totally reflected to reach face BC if:

[MOE]

  • sinθ < 8/9
  • sinθ > 8/9
  • sinθ < 2/3
  • sinθ > 2/3
57. The angle of minimum deviation for a prism (angle 60°) is 30°. The refractive index is:

[MOE]

  • √2
  • √3
  • 1.5
  • 2
58. A 60° prism (μ=1.414) gives minimum deviation when the angle of incidence is:

[MOE]

  • 60°
  • 45°
  • 90°
  • 30°
59. A prism (angle 45°, μ=1.6) has a minimum angle of incidence to prevent total internal reflection. This angle is:

[MOE]

  • 15.10°
  • 5.10°
  • 10.10°
  • Not possible
60. A prism (angle 60°, μ=1.5) produces maximum deviation. The angle of emergence is:

[IOM 2017]

  • 37°
  • 27.6°
  • 60°
  • 90°