Class 12 Physics Ch-9 Ray Optics MCQs Exam 2027

1. Ray Optics

A. Reflection, Refractive Index & Speed of Light

1. The radius of curvature of a plane mirror is: [BSEB]

   (A) Infinite

   (B) Zero

   (C) +5 cm

   (D) -5 cm

2. A virtual image larger than the object is formed by: [BSEB, 2024]

   (A) Convex mirror

   (B) Concave mirror

   (C) Plane mirror

   (D) None of these

3. The image formed by a plane mirror is: [BSEB, 2024]

   (A) Real

   (B) Virtual

   (C) Inverted

   (D) Smaller than the object

4. A ray of light is incident normally on a plane mirror. The angle of reflection will be: [BSEB, 2026]

   (A) $90^{\circ}$

   (B) $0^{\circ}$

   (C) Will not be reflected

   (D) None of these

5. The refractive index of diamond is close to: [BSEB, 2020]

   (A) 1

   (B) 1.5

   (C) 2.42

   (D) 4.14

6. The refractive index of water is: [BSEB, 2021]

   (A) 1.33

   (B) 1.5

   (C) 2.42

   (D) 1.0

7. $_1\mu_2$ is equal to: [BSEB, 2022]

   (A) $\frac{\mu_2}{\mu_1}$

   (B) $\frac{\mu_1}{\mu_2}$

   (C) $\mu_2 \cdot \mu_1$

   (D) $\frac{1}{\mu_1 \mu_2}$

8. Optical path is equal to: [BSEB, 2022]

   (A) Refractive index $\times$ Path length

   (B) Refractive index / Path length

   (C) Path length / Refractive index

   (D) $\frac{\text{Refractive index} \times \text{Path length}}{2}$

9. In a glass slab of refractive index $n$, the equivalent path length in vacuum for a path length $t$ is: [BSEB]

   (A) $(n – 1)t$

   (B) $nt$

   (C) $(\frac{n}{n-1})t$

   (D) None of these

10. For a beam of light going from medium I to medium II, the critical angle is $\theta$. If the velocity of light in medium I is $v$, then its velocity in medium II will be: [BSEB, 2018]

    (A) $v \sin \theta$

    (B) $v / \sin \theta$

    (C) $v \cos \theta$

    (D) $v / \cos \theta$

11. The velocity of light in vacuum is $c$. Its value in glass ($\mu = 3/2$) will be: [BSEB, 2021]

    (A) $\frac{3c}{2}$

    (B) $\frac{2c}{3}$

    (C) $\frac{4c}{3}$

    (D) $\frac{c}{2}$

12. With the increase in wavelength, the value of refractive index: [BSEB, 2022]

    (A) Increases

    (B) Decreases

    (C) Remains unchanged

    (D) None of these

13. The relation between refractive index ($n$) and wavelength ($\lambda$) of a transparent medium is:

    (A) $n = A\lambda + B$

    (B) $n = A + B\lambda^2$

    (C) $n = A + \frac{B}{\lambda}$

    (D) $n = A + \frac{B}{\lambda^2}$

14. The refractive index of water is 1.33. What will be the speed of light in water? [BSEB, 2026]

    (A) $1.33 \times 10^8$ m/s

    (B) $4 \times 10^8$ m/s

    (C) $2.25 \times 10^8$ m/s

    (D) $3 \times 10^8$ m/s

15. The ratio of refractive index of red light to blue light in air is: [BSEB, 2026]

    (A) Less than unity

    (B) Greater than unity

    (C) Equal to unity

    (D) None of these

16. The velocity of light is maximum in: [BSEB, 2020]

    (A) Air

    (B) Glass

    (C) Water

    (D) Vacuum

17. When light travels from one medium to another, the ray bends. This bending is called:

    (A) Interference

    (B) Dispersion

    (C) Refraction

    (D) Reflection

18. The bottom of a pond appears raised. This is due to:

    (A) Interference of light

    (B) Reflection of light

    (C) Refraction of light

    (D) Diffraction of light

19. When a ray of light enters a glass slab, its wavelength: [BSEB, 2015]

    (A) Decreases

    (B) Increases

    (C) Remains unchanged

    (D) Data is incomplete

20. The wavelength of blue light in air is $4200$ Å. Its wavelength in water ($\mu=4/3$) will be:

    (A) $2800$ Å

    (B) $5600$ Å

    (C) $3150$ Å

    (D) $4000$ Å

21. The field of view is maximum for: [BSEB, 2026]

    (A) Plane mirror

    (B) Convex mirror

    (C) Concave mirror

    (D) Cylindrical mirror

22. When light travels from one medium to another, the quantity that remains unchanged is: [BSEB, 2024]

    (A) Wavelength

    (B) Velocity

    (C) Frequency

    (D) Amplitude

23. A pinhole camera works on the principle of:

    (A) Refraction

    (B) Total Internal Reflection

    (C) Reflection

    (D) Rectilinear propagation of light

B. Total Internal Reflection (TIR) & Critical Angle

24. In the case of total internal reflection, the value of reflection coefficient is: [BSEB, 2023]

    (A) 0.5

    (B) 1

    (C) 0

    (D) $\infty$

25. The critical angle for glass is: [BSEB, 2022]

    (A) $20^\circ$

    (B) $30^\circ$

    (C) $48^\circ$

    (D) $42^\circ$ (Approx.)

26. The critical angle for diamond is: [BSEB, 2022]

    (A) $48.75^\circ$

    (B) $41.14^\circ$

    (C) $37.31^\circ$

    (D) $24.41^\circ$

27. The cause of a mirage is:

    (A) Refraction and Total Internal Reflection

    (B) Diffraction

    (C) Scattering

    (D) Interference

28. While entering air from glass, the critical angle is minimum for which color of light?

    (A) Red

    (B) Green

    (C) Yellow

    (D) Violet

29. If the critical angle for glass-air is $\theta$, then the refractive index of glass with respect to air is:

    (A) $\sin \theta$

    (B) $\text{cosec } \theta$

    (C) $\sin^2 \theta$

    (D) $1/\sin^2 \theta$

30. The critical angle will be maximum when light travels from:

    (A) Glass to Water

    (B) Glass to Air

    (C) Diamond to Air

    (D) Water to Air

31. An air bubble inside water shines due to:

    (A) Reflection

    (B) Refraction

    (C) Total Internal Reflection

    (D) Diffraction

32. Critical angle is that angle of incidence in a denser medium for which the angle of refraction in the rarer medium is:

    (A) $0^\circ$

    (B) $57^\circ$

    (C) $90^\circ$

    (D) $180^\circ$

C. Lenses and Combinations

33. The power of a convex lens is 2 Dioptre. Its focal length will be:

    (A) 20 cm

    (B) 50 cm

    (C) 40 cm

    (D) 60 cm

34. If two thin lenses of focal lengths $f_1$ and $f_2$ are in contact, the focal length of the combination is:

    (A) $\frac{f_1 + f_2}{2}$

    (B) $f_1 + f_2$

    (C) $\frac{f_1 f_2}{f_1 + f_2}$

    (D) $\frac{f_1 + f_2}{f_1 f_2}$

35. A convex lens is immersed in a liquid whose refractive index is equal to the refractive index of the lens material. Its focal length will: [BSEB, 2021]

    (A) Become zero

    (B) Become infinite

    (C) Decrease

    (D) Increase

36. Two convex lenses are kept in contact. The equivalent lens is:

    (A) Convex

    (B) Concave

    (C) Plano-concave

    (D) Cylindrical

37. The focal length of a lens of power 4 Dioptre is: [BSEB, 2022]

    (A) 0.25 m

    (B) 0.25 cm

    (C) 0.35 m

    (D) 0.35 cm

38. If the focal length of a glass lens ($\mu = 3/2$) in air is $f_a$ and in water ($\mu = 4/3$) is $f_w$, then: [BSEB, 2022]

    (A) $f_w = f_a$

    (B) $f_w = 2f_a$

    (C) $f_w = 3f_a$

    (D) $f_w = 4f_a$

39. A spherical mirror is immersed in water. Its focal length: [BSEB, 2023]

    (A) Decreases

    (B) Increases

    (C) Remains the same

    (D) None of these

40. A convex lens of focal length 40 cm and a concave lens of focal length 20 cm are in contact. The power of the combination in dioptres is: [BSEB, 2023]

    (A) 2.5

    (B) -2.5

    (C) 7.5

    (D) -7.5

41. The power of two lenses in contact is: [BSEB, 2024]

    (A) $P = P_1 + P_2$

    (B) $P = P_1 \times P_2$

    (C) $P = \frac{P_1}{P_2}$

    (D) $P = P_1(P_2 + P_1)$

42. Three lenses of focal lengths 15 cm, 25 cm, and 45 cm are placed in contact. The focal length of the combination is:

    (A) 40 cm

    (B) 35 cm

    (C) 20 cm

    (D) 10 cm

43. A convex lens ($\mu = 1.5$) is immersed in water ($\mu = 1.33$). It then behaves as: [BSEB, 2019]

    (A) Convex lens

    (B) Diverging lens

    (C) Prism

    (D) Concave mirror

44. Two lenses of power -15D and +5D are combined. The focal length of the combination will be: [BSEB, 2019]

    (A) -20 cm

    (B) -10 cm

    (C) +10 cm

    (D) None

45. The radii of curvature of a biconvex lens are 10 cm and 15 cm. If $\mu=1.5$, its focal length is:

    (A) 30 cm

    (B) 24 cm

    (C) 12 cm

    (D) 24 m

46. The focal length of a lens is 20 cm. Its power will be: [BSEB, 2020]

    (A) 20 Dioptre

    (B) 0.05 Dioptre

    (C) 0.5 Dioptre

    (D) 5 Dioptre

47. Two thin lenses in contact form a combination of power +10D. When separated by 0.25 m, the power becomes +6D. The focal lengths of the lenses in cm are:

    (A) 10, 16.7

    (B) 25, 16.67

    (C) 50, 12.5

    (D) 12.5, 12.5

48. When a concave glass lens is immersed in water, it becomes:

    (A) Less convergent

    (B) More convergent

    (C) Less divergent

    (D) More divergent

49. If the focal length of a lens is $f$ metres, then its power is:

    (A) $f$ Dioptre

    (B) $1/f$ Dioptre

    (C) $1-f$ Dioptre

    (D) $100/f$ Dioptre

50. If two converging lenses of focal length $f$ are placed in contact, the focal length of the combination is: [BSEB, 2015]

    (A) $f$

    (B) $2f$

    (C) $f/2$

    (D) $3f$

51. Three lenses of focal lengths 20 cm, -30 cm, and 60 cm are kept in contact. The focal length of the combination is:

    (A) 50 cm

    (B) 30 cm

    (C) 20 cm

    (D) 10 cm

52. The power of the combination of two lenses of focal lengths 20 cm and -40 cm will be:

    (A) +5 Dioptre

    (B) -5 Dioptre

    (C) +2.5 Dioptre

    (D) -2.5 Dioptre

53. The minimum distance between an object and its real image in a convex lens is:

    (A) More than $4f$

    (B) Less than $4f$

    (C) Equal to $2f$

    (D) Equal to $4f$

54. How many images will be formed by a lens if an object is placed on the principal axis (with different refractive indices)?

    (A) 1

    (B) 2

    (C) 3

    (D) 7

55. A biconvex lens ($\mu = 1.5$) has radii of curvature 20 cm each. The power of the lens is:

    (A) 5D

    (B) 10D

    (C) 2.5D

    (D) 20D

56. The SI unit of power of a lens is: [BSEB]

    (A) Joule

    (B) Dioptre

    (C) Candela

    (D) Watt

57. When a ray of white light enters a lens, which of the following changes?

    (A) Velocity and Wavelength

    (B) Wavelength only

    (C) Velocity only

    (D) Frequency

D. Prism, Dispersion & Scattering

58. The refractive index of the material of a prism is: [BSEB, 2022]

    (A) $\mu = \frac{\sin((A+\delta_m)/2)}{\sin(A/2)}$

    (B) $\mu = \frac{\sin(A/2)}{\sin((A+\delta_m)/2)}$

    (C) $\mu = \frac{\sin((A+\delta_m)/2)}{\cos(A/2)}$

    (D) $\mu = \frac{\sin((A+\delta_m)/2)}{\sin(A)}$

59. Angular dispersion is equal to: [BSEB, 2021]

    (A) $(\mu_v – \mu_r)A$

    (B) $(\mu_v – \mu_r)$

    (C) $(\mu_v + \mu_r)A$

    (D) $(\mu_v + \mu_r)$

60. For the refractive index of the mean color (yellow), which of the following is correct? [BSEB, 2021]

    (A) $\mu = \frac{\mu_r + \mu_v}{2}$

    (B) $\mu = \frac{\mu_r – \mu_v}{2}$

    (C) $\mu = \frac{\mu_r}{2}$

    (D) $\mu = \frac{\mu_v}{2}$

61. For dispersive power, which of the following relations is correct? [BSEB, 2022]

    (A) $\omega = \frac{\mu_v – \mu_r}{\mu_y – 1}$

    (B) $\omega = \frac{\mu_v – \mu_r}{\mu_y}$

    (C) $\omega = \frac{\mu_y – 1}{\mu_v – \mu_r}$

    (D) $\omega = \frac{\mu_v – \mu_y}{\mu_r – 1}$

62. The dispersive power of a prism depends on: [BSEB, 2023]

    (A) Angle of incidence

    (B) Nature of the material of the prism

    (C) Refracting angle of the prism

    (D) Mean angle of the prism

63. The angle of minimum deviation for a thin prism of refractive index $n$ and prism angle A is: [BSEB, 2019]

    (A) $(1 – n)A$

    (B) $(n – 1)A$

    (C) $(n + 1)A$

    (D) $(1 + n)A^2$

64. The spectrum of sunlight is: [BSEB, 2019, 2026]

    (A) Continuous

    (B) Line spectrum

    (C) Black line spectrum

    (D) Black band spectrum

65. Rainbow is formed due to: [BSEB, 2024]

    (A) Scattering

    (B) Diffraction

    (C) Dispersion

    (D) Refraction

66. In a spectrum produced by a prism, the deviation of red light is minimum because its speed:

    (A) Is more than all other colors

    (B) Is less than all other colors

    (C) Is equal to the average speed

    (D) Is greatly slowed down in the prism

67. For a thin prism of glass ($n = 1.5$), the relation between angle of minimum deviation $\delta_m$ and refracting angle $r$ is:

    (A) $\delta_m = r$

    (B) $\delta_m = 1.5r$

    (C) $\delta_m = 2r$

    (D) $\delta_m = 0.5r$

68. The refractive index of a prism material is $\sqrt{2}$ and the refracting angle is $60^\circ$. For minimum deviation, the angle of incidence should be:

    (A) $30^\circ$

    (B) $45^\circ$

    (C) $60^\circ$

    (D) $75^\circ$

69. The condition for dispersion without deviation is: [BSEB, 2023]

    (A) $(\mu – 1)A = (\mu’ – 1)A’$

    (B) $(\mu_v – \mu_r)A = (\mu’_v – \mu’_r)A’$

    (C) $(\mu_y – 1)A = (\mu’_y – 1)A’$

    (D) $A = A’$

70. The angle of minimum deviation for a thin prism is: [BSEB, 2024]

    (A) $(n-1)A$

    (B) $(n+1)A$

    (C) $nA$

    (D) $(1-n)A$

71. Which relation is correct for the intensity of scattered light ($I$) and wavelength ($\lambda$)? [BSEB, 2022]

    (A) $I \propto \frac{1}{\lambda}$

    (B) $I \propto \frac{1}{\lambda^2}$

    (C) $I \propto \frac{1}{\lambda^3}$

    (D) $I \propto \frac{1}{\lambda^4}$

72. The blue color of the sky is due to: [BSEB, 2024]

    (A) Scattering

    (B) Interference

    (C) Polarization

    (D) Diffraction

73. In the absence of atmosphere, the color of the sky from Earth would appear:

    (A) Black

    (B) Blue

    (C) Orange

    (D) Red

74. A pulse of white light is incident normally on a glass slab. Which color will emerge first?

    (A) Blue

    (B) Green

    (C) Violet

    (D) Red

75. The black lines in the solar spectrum are called: [BSEB, 2023]

    (A) Fraunhofer lines

    (B) Telescopic lines

    (C) Raman lines

    (D) None of these

E. Human Eye and Defects of Vision

76. Cylindrical lenses are used to correct which eye defect? [BSEB, 2019]

    (A) Myopia (Short-sightedness)

    (B) Hypermetropia (Long-sightedness)

    (C) Astigmatism

    (D) Presbyopia

77. The least distance of distinct vision for a healthy person is: [BSEB, 2021]

    (A) 25 cm

    (B) 50 cm

    (C) 100 cm

    (D) Infinite

78. Which eye defect is corrected using a convex lens? [BSEB, 2024]

    (A) Myopia

    (B) Hypermetropia

    (C) Presbyopia

    (D) Astigmatism

79. The focal length of the eye lens of a healthy person is about: [BSEB, 2021, 2026]

    (A) 1 mm

    (B) 2 cm

    (C) 25 cm

    (D) 1 m

80. The defect of vision caused by the curvature of the cornea in different planes is:

    (A) Myopia

    (B) Hypermetropia

    (C) Astigmatism

    (D) Presbyopia

81. A person with long-sightedness (Hypermetropia) needs:

    (A) Convex lens

    (B) Concave lens

    (C) Cylindrical lens

    (D) Plano-concave lens

82. To correct myopia, the lens used is: [BSEB, 2024]

    (A) Sphero-cylindrical lens

    (B) Concave lens

    (C) Convex lens

    (D) Concavo-convex lens

83. The image formed on the retina of the human eye is: [BSEB, 2024]

    (A) Virtual, Erect

    (B) Real, Erect

    (C) Virtual, Inverted

    (D) Real, Inverted

84. An eye with myopia can see clearly: [BSEB, 2024]

    (A) Distant objects

    (B) Nearby objects

    (C) Large objects

    (D) Only small objects

85. A person uses spectacles of power +2D. The defect of vision is:

    (A) Myopia

    (B) Hypermetropia

    (C) Presbyopia

    (D) Astigmatism

86. A person wears spectacles of power -2.5 D. The defect and the far point without glasses are:

    (A) Hypermetropia, 40 cm

    (B) Myopia, 40 cm

    (C) Astigmatism, 40 cm

    (D) Myopia, 250 cm

87. To remove hypermetropia, the lens used is: [BSEB, 2026]

    (A) Convex

    (B) Concave

    (C) Cylindrical

    (D) Plano-convex

F. Optical Instruments (Microscope & Telescope)

88. In an astronomical telescope, the focal lengths of objective and eyepiece are $f_o$ and $f_e$ respectively. For normal adjustment, the angular magnification is:

    (A) $f_o + f_e$

    (B) $f_o – f_e$

    (C) $f_o / f_e$

    (D) $f_e / f_o$

89. The magnifying power of an astronomical telescope is: [BSEB, 2022]

    (A) $\frac{f_o}{f_e}$

    (B) $-\frac{f_o}{f_e}$

    (C) $\frac{f_e}{f_o}$

    (D) $-\frac{f_e}{f_o}$

90. In normal adjustment, the length of the tube of an astronomical telescope will be: [BSEB, 2021]

    (A) $f_o – f_e$

    (B) $f_o \times f_e$

    (C) $\frac{f_o}{f_e}$

    (D) $f_o + f_e$

91. Which relation is correct for the magnifying power of a compound microscope? [BSEB, 2020]

    (A) $M = \frac{L}{f_0} (1 + \frac{D}{f_e})$

    (B) $M = -\frac{L}{f_0} (1 + \frac{D}{f_e})$

    (C) $M = (1 + \frac{D}{f_e})$

    (D) $M = (1 – \frac{D}{f_e})$

92. The image formed by a simple microscope is: [BSEB, 2021]

    (A) Virtual and Erect

    (B) Virtual and Inverted

    (C) Real and Erect

    (D) Real and Inverted

93. For an astronomical telescope, which of the following is correct? [BSEB, 2021]

    (A) $f_o = f_e$

    (B) $f_o > f_e$

    (C) $f_o < f_e$

    (D) $f_o \ll f_e$

94. The powers of lenses in an astronomical telescope are 0.5 D and 20 D. Its magnifying power will be:

    (A) 50

    (B) 10

    (C) 100

    (D) 40

95. In an astronomical telescope, the final image is: [BSEB, 2016, 2017]

    (A) Real and Erect

    (B) Real and Inverted

    (C) Virtual and Erect

    (D) Virtual and Inverted

96. When the tube length of a microscope is increased, its magnifying power: [BSEB, 2020, 2024, 2026]

    (A) Increases

    (B) Decreases

    (C) Becomes zero

    (D) Remains unchanged

97. The magnifying power of a simple microscope is: [BSEB, 2022]

    (A) $D + f$

    (B) $D + \frac{1}{f}$

    (C) $1 + \frac{D}{f}$

    (D) $\frac{D}{f} – 1$

98. The focal length of the objective of a telescope is 60 cm. To get a magnification of 20, the focal length of the eyepiece should be: [BSEB, 2026]

    (A) 2 cm

    (B) 3 cm

    (C) 4 cm

    (D) 5 cm

99. A magnifying glass of power 12 D has a magnifying power of:

    (A) 4

    (B) 1200

    (C) 3

    (D) 25

100. The power of a magnifying glass is: [BSEB 2026]

     (A) $1 + D/f$

     (B) $D/f$

     (C) $1 – D/f$

     (D) $f/D$

101. Chromatic aberration is not found in:

     (A) Refracting telescope

     (B) Reflecting telescope

     (C) Both ‘A’ and ‘B’

     (D) None of these

102. The focal lengths of the objective and eyepiece of a telescope are 20 cm and 2 cm respectively. Its magnifying power is:

     (A) 2

     (B) 10

     (C) 20

     (D) 22

103. The magnifying power of a simple microscope increases if:

     (A) Focal length of the lens increases

     (B) Focal length of the lens decreases

     (C) Diameter of the lens increases

     (D) Diameter of the lens decreases

2. Wave Optics

G. Wavefront and Huygens’ Principle

104. The line perpendicular to a wavefront is called: [BSEB, 2024]

     (A) Ray

     (B) Wave

     (C) Phase difference

     (D) None of these

105. The concept of secondary wavelets was given by: [BSEB, 2022]

     (A) Fresnel

     (B) Newton

     (C) Huygens

     (D) Maxwell

106. At a finite distance from a point source, the wavefront is: [BSEB, 2026]

     (A) Plane

     (B) Circular

     (C) Cylindrical

     (D) Spherical

107. The proponent of the corpuscular theory of light was: [BSEB, 2022]

     (A) Huygens

     (B) Newton

     (C) Maxwell

     (D) Young

108. Light travels in the form of which type of waves? [BSEB, 2023]

     (A) Transverse wave

     (B) Longitudinal wave

     (C) Both (A) and (B)

     (D) None of these

109. The reason for rectilinear propagation of light is: [BSEB 2018]

     (A) Wave nature of light

     (B) Particle nature of light

     (C) High velocity of light

     (D) Short wavelength of light

H. Interference

110. For destructive interference, the path difference must be: [BSEB, 2021, 2023, 2026]

     (A) $n\lambda$

     (B) $(2n + 1)\frac{\lambda}{2}$

     (C) Zero

     (D) Infinite

111. For constructive interference, the phase difference ($\phi$) between two waves at a point should be: [BSEB, 2021]

     (A) Zero

     (B) $\pi$

     (C) $\pi/2$

     (D) $3\pi/4$

112. Two sources of light are said to be ‘coherent’ if their:

     (A) Amplitudes are same

     (B) Wavelengths are same

     (C) Phase difference is constant

     (D) Velocities are same

113. A soap bubble appears colored in sunlight due to:

     (A) Scattering of light

     (B) Interference of light

     (C) Diffraction of light

     (D) Refraction of light

114. The color of a thin film is due to: [BSEB, 2021]

     (A) Scattering

     (B) Interference

     (C) Diffraction

     (D) Dispersion

115. The maximum intensity produced by the interference of two waves $y_1 = 4 \sin \omega t$ and $y_2 = 3 \cos \omega t$ will be:

     (A) 7

     (B) 5

     (C) 25

     (D) 1

116. The relation between phase difference $(\phi)$ and path difference $(\Delta x)$ is: [BSEB 2022, 2026]

     (A) $\phi = (2\pi/\lambda) \Delta x$

     (B) $\phi = (\pi/\lambda) \Delta x$

     (C) $\phi = (\lambda/2\pi) \Delta x$

     (D) None of these

I. Polarization and Diffraction

117. Brewster’s law is: [BSEB, 2022]

     (A) $\mu = \sin i_p$

     (B) $\mu = \cos i_p$

     (C) $\mu = \tan i_p$

     (D) $\mu = \tan^2 i_p$

118. The transverse nature of light waves is confirmed by:

     (A) Interference

     (B) Reflection

     (C) Polarization

     (D) Dispersion

119. Natural light obtained from the Sun is: [BSEB, 2026]

     (A) Polarized

     (B) Unpolarized

     (C) Partially polarized

     (D) Linearly polarized

3. Miscellaneous & Other Important Questions

120. Light-year is the unit of which physical quantity? [BSEB, 2021]

     (A) Distance

     (B) Time

     (C) Energy

     (D) Intensity of light

121. The inverse square law of intensity ($I \propto \frac{1}{r^2}$) is applicable for: [BSEB, 2026]

     (A) Point source

     (B) Linear source

     (C) Cylindrical source

     (D) Plane source

122. The power of a glass slab with parallel surfaces is: [BSEB, 2021]

     (A) Infinite

     (B) Zero

     (C) 100 cm

     (D) 10 cm

123. The cause of the color of light is: [BSEB, 2019]

     (A) Its frequency

     (B) Its velocity

     (C) Its phase

     (D) Its amplitude

124. If the energy of a photon of blue light is $E_1$ and that of yellow light is $E_2$, then:

     (A) $E_1 = E_2$

     (B) $E_1 > E_2$

     (C) $E_1 < E_2$

     (D) $E_1 = 2E_2$

125. Which color has the shortest wavelength? [BSEB, 2024]

     (A) Violet

     (B) Yellow

     (C) Blue

     (D) Red

126. A ray of light is incident on a glass plate at an angle of $60^\circ$ ($\mu = \sqrt{3}$). The angle between reflected and refracted rays will be:

     (A) $40^\circ$

     (B) $60^\circ$

     (C) $80^\circ$

     (D) $90^\circ$

127. The nature of an electron beam moving with the same velocity in the same direction will be: [BSEB, 2023]

     (A) Converging

     (B) Diverging

     (C) Parallel

     (D) None of these

128. Which of the following is used in lenses to reduce chromatic aberration?

     (A) Convex lens

     (B) Concave lens

     (C) Achromatic combination

     (D) Cylindrical lens

129. A ray of light does not deviate:

     (A) When reflected normally from a plane mirror

     (B) When reflected obliquely from a plane mirror

     (C) When passing through a prism

     (D) When passing through parallel surfaces of a rectangular slab

130. Dispersion of white light by a medium is possible only when the medium:

     (A) Is water

     (B) Is glass

     (C) Is any transparent medium

     (D) Is not any transparent medium

131. A ray of light travels from glass ($\mu = 5/3$) to water ($\mu = 4/3$). The critical angle will be: [BSEB, 2019]

     (A) $\sin^{-1}(1/2)$

     (B) $\sin^{-1}(4/5)$

     (C) $\sin^{-1}(5/6)$

     (D) None of these

132. Which of the following has the maximum refractive index? [BSEB, 2020]

     (A) Glass

     (B) Water

     (C) Iron

     (D) Diamond

133. A convex lens is immersed in a liquid of same refractive index. Its focal length: [BSEB 2018]

     (A) Becomes zero

     (B) Becomes infinite

     (C) Decreases

     (D) Increases

134. Speed of light in vacuum is $c$. Its speed in glass ($\mu = 1.5$) will be: [BSEB 2021]

     (A) $3c/2$

     (B) $2c/3$

     (C) $4c/3$

     (D) $c/2$

135. The unit of power of a lens is: [BSEB 2021]

     (A) Joule

     (B) Watt

     (C) Candela

     (D) Dioptre

136. Focal length of objective of telescope is 60 cm. For 20x magnification, focal length of eyepiece should be:

     (A) 2 cm

     (B) 3 cm

     (C) 4 cm

     (D) 5 cm

137. If $\mu_w = 4/3$ and $\mu_g = 3/2$, then $_w\mu_g$ is: [BSEB, 2022]

     (A) 2

     (B) $1/2$

     (C) $9/8$

     (D) $8/9$

138. The focal length of a lens is 20 cm. Its power is: [BSEB, 2020]

     (A) 20 Dioptre

     (B) 0.05 Dioptre

     (C) 0.5 Dioptre

     (D) 5 Dioptre

139. Light-year is the unit of: [BSEB, 2021]

     (A) Distance

     (B) Time

     (C) Energy

     (D) Intensity

140. Black lines in solar spectrum are: [BSEB 2023]

     (A) Fraunhofer lines

     (B) Telescopic lines

     (C) Raman lines

     (D) None of these

141. By increasing tube length of microscope, magnifying power: [BSEB, 2026]

     (A) Increases

     (B) Decreases

     (C) Becomes zero

     (D) Remains unchanged

142. Focal length of a healthy eye lens is approx: [BSEB 2026]

     (A) 1 mm

     (B) 2 cm

     (C) 25 cm

     (D) 1 m

143. Angle of reflection for a ray incident normally on plane mirror: [BSEB 2026]

     (A) $0^\circ$

     (B) $90^\circ$

     (C) $180^\circ$

     (D) $45^\circ$

144. Relation between phase difference $(\phi)$ and path difference $(\Delta x)$ is: [BSEB 2026]

     (A) $\phi = (2\pi/\lambda) \Delta x$

     (B) $\phi = (\pi/\lambda) \Delta x$

     (C) $\phi = (\lambda/2\pi) \Delta x$

     (D) None of these

145. Cylindrical lens is used for: [BSEB 2026]

     (A) Myopia

     (B) Hypermetropia

     (C) Astigmatism

     (D) Presbyopia

146. Critical angle is maximum for light going from:

     (A) Glass to Water

     (B) Glass to Air

     (C) Diamond to Air

     (D) Water to Air

147. Optical path is: [BSEB 2022]

     (A) $\mu \times$ path length

     (B) $\mu$ / path length

     (C) path length / $\mu$

     (D) None of these

148. Secondary wavelets concept was given by: [BSEB 2022]

     (A) Fresnel

     (B) Newton

     (C) Huygens

     (D) Maxwell

149. Brewster’s Law: [BSEB 2022]

     (A) $\mu = \sin i_p$

     (B) $\mu = \cos i_p$

     (C) $\mu = \tan i_p$

     (D) $\mu = \tan^2 i_p$

150. Dispersive power relation: [BSEB 2022]

     (A) $\omega = \frac{\mu_v – \mu_r}{\mu_y – 1}$

     (B) $\omega = \frac{\mu_v – \mu_r}{\mu_y}$

     (C) $\omega = \frac{\mu_y – 1}{\mu_v – \mu_r}$

     (D) $\omega = \frac{\mu_v – \mu_y}{\mu_r – 1}$

151. Magnifying power of astronomical telescope: [BSEB 2022]

     (A) $\frac{f_o}{f_e}$

     (B) $-\frac{f_o}{f_e}$

     (C) $\frac{f_e}{f_o}$

     (D) $-\frac{f_e}{f_o}$

152. Correct relation for compound microscope: [BSEB 2020]

     (A) $M = \frac{L}{f_0} (1 + \frac{D}{f_e})$

     (B) $M = -\frac{L}{f_0} (1 + \frac{D}{f_e})$

     (C) $M = (1 + \frac{D}{f_e})$

     (D) $M = (1 – \frac{D}{f_e})$

153. Unit of light-year: [BSEB 2021]

     (A) Distance

     (B) Time

     (C) Energy

     (D) Intensity

154. For astronomical telescope, which is correct: [BSEB 2021]

     (A) $f_o = f_e$

     (B) $f_o > f_e$

     (C) $f_o < f_e$

     (D) $f_o \ll f_e$

155. Refractive index for mean color: [BSEB 2021]

     (A) $\mu = \frac{\mu_r + \mu_v}{2}$

     (B) $\mu = \frac{\mu_r – \mu_v}{2}$

     (C) $\mu = \frac{\mu_r}{2}$

     (D) $\mu = \frac{\mu_v}{2}$

156. Ray incident normally on plane mirror. Angle of reflection: [BSEB 2026]

     (A) $90^{\circ}$

     (B) $0^{\circ}$

     (C) No reflection

     (D) None

157. Increasing microscope tube length, magnifying power: [BSEB 2026]

     (A) Increases

     (B) Decreases

     (C) Zero

     (D) Constant

158. Speed of light in water ($\mu = 1.33$): [BSEB 2026]

     (A) $1.33 \times 10^8$ m/s

     (B) $4 \times 10^8$ m/s

     (C) $2.25 \times 10^8$ m/s

     (D) $3 \times 10^8$ m/s

159. Lens for hypermetropia: [BSEB 2026]

     (A) Convex

     (B) Concave

     (C) Cylindrical

     (D) Plano-convex

160. Capacity of magnifying glass: [BSEB 2026]

     (A) $1 + D/f$

     (B) $D/f$

     (C) $1 – D/f$

     (D) $f/D$