Class 12 Physics Ch-10 Wave Optics MCQs Exam 2027

Physics: Optics Practice Paper (BSEB 2026)

Topic 1: Reflection of Light & Spherical Mirrors

1. The angle of reflection for a ray incident normally on a plane mirror is: [BSEB 2026]

   (A) $0^\circ$

   (B) $90^\circ$

   (C) $180^\circ$

   (D) $45^\circ$

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

   (A) Plane mirror

   (B) Convex mirror

   (C) Concave mirror

   (D) Cylindrical mirror

3. In which mirror is the image of an object always virtual, erect, and diminished?

   (A) Concave mirror

   (B) Convex mirror

   (C) Plane mirror

   (D) None of these

4. The focal length of a plane mirror is:

   (A) Zero

   (B) Infinite

   (C) 25 cm

   (D) -25 cm

5. The formula for magnification ($m$) in a spherical mirror is:

   (A) $-v/u$

   (B) $v/u$

   (C) $u/v$

   (D) $-u/v$

Topic 2: Refraction of Light & Total Internal Reflection (TIR)

6. The reason for the blue color of the sky is: [BSEB 2019]

   (A) Scattering of light

   (B) Interference of light

   (C) Diffraction of light

   (D) Polarization of light

7. The reason for a Mirage is: [BSEB 2025]

   (A) Total Internal Reflection

   (B) Diffraction

   (C) Scattering

   (D) Interference

8. When a ray of light enters from air to glass, its wavelength:

   (A) Increases

   (B) Decreases

   (C) Remains unchanged

   (D) Becomes zero

9. The refractive index of diamond is approximately: [BSEB 2021]

   (A) 1

   (B) 1.5

   (C) 2.42

   (D) 4.14

10. Optical Fibre works on which principle? [BSEB 2021]

    (A) Diffraction

    (B) Interference

    (C) Total Internal Reflection

    (D) Scattering

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

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

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

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

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

12. The ratio of the refractive index of red light and blue light in air is: [BSEB 2026]

    (A) Less than one

    (B) More than one

    (C) Equal to one

    (D) None of these

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

    (A) $0^\circ$

    (B) $45^\circ$

    (C) $90^\circ$

    (D) $180^\circ$

14. With the increase in wavelength, the refractive index of a medium:

    (A) Increases

    (B) Decreases

    (C) Remains unchanged

    (D) First increases then decreases

15. When light enters from one medium to another, which quantity remains unchanged? [BSEB 2021]

    (A) Velocity

    (B) Wavelength

    (C) Frequency

    (D) Amplitude

16. The refractive indices of water and glass are $4/3$ and $3/2$ respectively. The refractive index of water relative to glass will be: [BSEB 2019]

    (A) 2

    (B) 1/2

    (C) 9/8

    (D) 8/9

17. The critical angle for glass is approximately: [BSEB 2022]

    (A) $20^\circ$

    (B) $30^\circ$

    (C) $42^\circ$

    (D) $48^\circ$

18. The speed of light is maximum in vacuum; its value is:

    (A) $3 \times 10^8 \text{ m/s}$

    (B) $3 \times 10^{10} \text{ m/s}$

    (C) $2 \times 10^8 \text{ m/s}$

    (D) $1.5 \times 10^8 \text{ m/s}$

19. The bending of a ray of light when it goes from one medium to another is called:

    (A) Reflection

    (B) Refraction

    (C) Diffraction

    (D) Interference

20. The wavelength of light in vacuum is $\lambda_0$. Its value in a medium of refractive index $\mu$ will be:

    (A) $\mu \lambda_0$

    (B) $\lambda_0 / \mu$

    (C) $\lambda_0 / \mu^2$

    (D) $\lambda_0$

21. Critical angle for diamond is: [BSEB 2021]

    (A) $24.41^\circ$

    (B) $37.31^\circ$

    (C) $48.75^\circ$

    (D) $41.14^\circ$

22. The refractive index of air is:

    (A) 0

    (B) 1

    (C) 1.33

    (D) 1.5

Topic 3: Lenses & Optical Instruments

23. A convex lens is immersed in a liquid whose refractive index is equal to the refractive index of the material of the lens. Then its focal length: [BSEB 2020]

    (A) Will become zero

    (B) Will become infinite

    (C) Will decrease

    (D) Will increase

24. Two convex lenses in contact with each other form an equivalent lens which is: [BSEB 2022]

    (A) Convex

    (B) Concave

    (C) Cylindrical

    (D) Plano-convex

25. Which of the following relations is correct for the magnifying power of a compound microscope? [BSEB 2020]

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

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

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

    (D) None of these

26. The image formed by a simple microscope is: [BSEB 2011]

    (A) Virtual and erect

    (B) Virtual and inverted

    (C) Real and erect

    (D) Real and inverted

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

    (A) Joule

    (B) Candela

    (C) Dioptre

    (D) Watt

28. The final image in an astronomical telescope is: [BSEB 2024]

    (A) Real and erect

    (B) Real and inverted

    (C) Virtual and erect

    (D) Virtual and inverted

29. The resolving power of a telescope depends on:

    (A) Focal length

    (B) Diameter of the aperture

    (C) Length of the tube

    (D) None of these

30. Lens maker’s formula is: [BSEB 2020]

    (A) $\frac{1}{f} = (\mu-1)(\frac{1}{R_1} – \frac{1}{R_2})$

    (B) $\frac{1}{f} = (\mu+1)(\frac{1}{R_1} + \frac{1}{R_2})$

    (C) $\frac{1}{f} = \mu(\frac{1}{R_1} – \frac{1}{R_2})$

    (D) None of these

31. Which of the following is correct for an astronomical telescope? [BSEB 2021]

    (A) $f_o = f_e$

    (B) $f_o > f_e$

    (C) $f_o < f_e$

    (D) $f_o \ll f_e$

32. The length (L) of an astronomical telescope for normal adjustment is: [BSEB 2020]

    (A) $f_o – f_e$

    (B) $f_o \times f_e$

    (C) $f_o + f_e$

    (D) $f_o / f_e$

33. If the upper half of a convex lens is covered with black paper, the image:

    (A) Size will become half

    (B) Intensity will decrease

    (C) Will disappear

    (D) Will be inverted

34. On increasing the length of the tube of a microscope, its magnifying power: [BSEB 2026]

    (A) Increases

    (B) Decreases

    (C) Becomes zero

    (D) Remains unchanged

35. One Dioptre is equal to:

    (A) $1 \text{ m}$

    (B) $1 \text{ m}^{-1}$

    (C) $1 \text{ cm}^{-1}$

    (D) $1 \text{ mm}^{-1}$

36. The image formed by the objective of a compound microscope is:

    (A) Real and small

    (B) Real and magnified

    (C) Virtual and magnified

    (D) Virtual and small

37. The relation between power (P) and focal length (f) of a lens is:

    (A) $P = f$

    (B) $P = 1/f$

    (C) $P = f^2$

    (D) $P = 2f$

38. The focal length of a lens is maximum for:

    (A) Red color

    (B) Violet color

    (C) Yellow color

    (D) Green color

39. Two thin lenses of power $P_1$ and $P_2$ are placed in contact. The equivalent power will be:

    (A) $P_1 + P_2$

    (B) $P_1 – P_2$

    (C) $P_1 \times P_2$

    (D) $P_1 / P_2$

40. The focal length of a lens is 20 cm. Its power will be:

    (A) 2D

    (B) 5D

    (C) 0.5D

    (D) 20D

41. Which part of the camera acts like the retina of the eye?

    (A) Lens

    (B) Film

    (C) Shutter

    (D) Aperture

42. When an object is placed at $2F$ of a convex lens, the image is formed at:

    (A) $F$

    (B) $2F$

    (C) Infinity

    (D) Between $F$ and $2F$

43. How many images will be formed by a lens if the object is on the principal axis and the lens is made of two different materials?

    (A) 1

    (B) 2

    (C) 3

    (D) Infinite

44. Power of a lens depends on $(\mu – 1)$. If $\mu$ increases, the power:

    (A) Increases

    (B) Decreases

    (C) Remains same

    (D) Becomes zero

45. A lens of power $+2D$ has a focal length of:

    (A) 50 cm

    (B) -50 cm

    (C) 20 cm

    (D) 100 cm

Topic 4: Human Eye & Defects of Vision

46. The least distance of distinct vision for a normal eye is: [BSEB 2022]

    (A) 100 cm

    (B) 50 cm

    (C) 25 cm

    (D) 0 cm

47. To remove Short-sightedness (Myopia), we use: [BSEB 2026]

    (A) Convex lens

    (B) Concave lens

    (C) Cylindrical lens

    (D) Bifocal lens

48. To remove Long-sightedness (Hypermetropia), the lens used is: [BSEB 2026]

    (A) Convex

    (B) Concave

    (C) Cylindrical

    (D) Plano-convex

49. Cylindrical lenses are used for: [BSEB 2026]

    (A) Myopia

    (B) Hypermetropia

    (C) Astigmatism

    (D) Presbyopia

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

    (A) 1 mm

    (B) 2 cm

    (C) 25 cm

    (D) 1 m

51. Bifocal lenses are used to correct:

    (A) Myopia

    (B) Hypermetropia

    (C) Presbyopia

    (D) Astigmatism

52. In which eye defect can a person see near objects clearly but not far objects?

    (A) Myopia

    (B) Hypermetropia

    (C) Astigmatism

    (D) Cataract

53. The resolution limit of a healthy eye is:

    (A) $1’$

    (B) $1”$

    (C) $1^\circ$

    (D) $0.5^\circ$

54. The ability of the eye lens to change its focal length is called:

    (A) Dispersion

    (B) Power of Accommodation

    (C) Reflection

    (D) Refraction

55. The image formed on the retina is:

    (A) Real and erect

    (B) Real and inverted

    (C) Virtual and erect

    (D) Virtual and inverted

56. The maximum distance of distinct vision for a healthy eye is:

    (A) 25 cm

    (B) 50 cm

    (C) 100 cm

    (D) Infinite

Topic 5: Prism & Dispersion of Light

57. When white light is incident on a prism, the maximum deviation is for which color? [BSEB 2024]

    (A) Red

    (B) Yellow

    (C) Violet

    (D) Blue

58. The minimum angle of deviation for a thin prism (refractive index $\mu$) is: [BSEB 2021]

    (A) $(1-\mu)A$

    (B) $(\mu-1)A$

    (C) $(\mu+1)A$

    (D) $(\mu+1)A^2$

59. The reason for the formation of a rainbow is: [BSEB 2019]

    (A) Scattering

    (B) Diffraction

    (C) Dispersion

    (D) Interference

60. The value of dispersive power ($\omega$) is: [BSEB 2021]

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

    (B) $\frac{\mu_v + \mu_r}{\mu_y – 1}$

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

    (D) None of these

61. Which color is on the outside in a primary rainbow?

    (A) Violet

    (B) Red

    (C) Blue

    (D) Green

62. Which color is on the outside in a secondary rainbow?

    (A) Red

    (B) Violet

    (C) Yellow

    (D) None of these

63. When a ray of white light passes through a prism, the angle of deviation is minimum for:

    (A) Red

    (B) Violet

    (C) Yellow

    (D) Blue

64. In Rayleigh scattering, the intensity of scattered light ($I$) is inversely proportional to which power of wavelength ($\lambda$)?

    (A) $\lambda$

    (B) $\lambda^2$

    (C) $\lambda^3$

    (D) $\lambda^4$

65. The sun appears red at sunrise and sunset due to:

    (A) Reflection

    (B) Diffraction

    (C) Scattering

    (D) Refraction

66. The spectrum of sunlight is: [BSEB 2026]

    (A) Continuous

    (B) Line spectrum

    (C) Black line spectrum

    (D) Black band spectrum

67. The formula to find the refractive index of the material of a prism is:

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

    (B) $\mu = \frac{\cos[(A+\delta_m)/2]}{\cos(A/2)}$

    (C) $\mu = \tan(A/2)$

    (D) None of these

68. The refractive index of glass is maximum for which color?

    (A) Red

    (B) Yellow

    (C) Blue

    (D) Violet

Topic 6: Wave Optics & Huygens’ Principle

69. According to Huygens, light waves are:

    (A) Mechanical, longitudinal

    (B) Mechanical, transverse

    (C) Electromagnetic

    (D) Mechanical, spherical

70. The concept of secondary wavelets was given by: [BSEB 2023]

    (A) Fresnel

    (B) Newton

    (C) Huygens

    (D) Maxwell

    [Image showing Huygens’ principle of secondary wavelets forming a new wavefront]

71. Huygens’ principle of secondary wavelets is used to:

    (A) Determine the speed of light

    (B) Find the new position of a wavefront

    (C) Explain interference

    (D) None of these

72. The wavefront due to a point source at a finite distance is: [BSEB 2026]

    (A) Spherical

    (B) Cylindrical

    (C) Planar

    (D) Circular

73. What is the shape of the wavefront produced by a convex lens when the light source is at focus?

    (A) Cylindrical

    (B) Planar

    (C) Spherical

    (D) None of these

74. The line drawn perpendicular to a wavefront is called:

    (A) Ray

    (B) Wave

    (C) Diffraction

    (D) None of these

75. Every point on a wavefront is considered as:

    (A) A new light source

    (B) A disturbance

    (C) Secondary wavelet

    (D) Both ‘A’ and ‘C’

76. According to the wave theory of light, the color-determining factor of light is:

    (A) Amplitude

    (B) Speed of wave

    (C) Frequency

    (D) Wavelength

77. Two sources of waves are said to be coherent if: [BSEB 2026]

    (A) Both produce wavefronts of same shape

    (B) Both produce waves of same wavelength

    (C) Both produce waves of same velocity

    (D) They produce waves of same wavelength with a constant phase difference

78. A wavefront is the locus of points vibrating in the same phase. This statement is:

    (A) True

    (B) False

    (C) Partially true

    (D) None of these

79. The value of Fresnel distance $Z_F$ is:

    (A) $\frac{a}{\lambda}$

    (B) $\frac{a^2}{\lambda}$

    (C) $\frac{\lambda}{a}$

    (D) $\frac{\lambda}{a^2}$

Topic 7: Interference of Light

80. In Young’s experiment, if the wavelength of light is doubled, the fringe width:

    (A) Remains same

    (B) Becomes double

    (C) Remains half

    (D) Becomes four times

81. For destructive interference, the phase difference $(\phi)$ between waves at a point should be: [BSEB 2014]

    (A) Even multiple of $\pi$

    (B) Odd multiple of $\pi$

    (C) Even multiple of $\pi/2$

    (D) Zero

82. Two waves with intensities in the ratio $9 : 1$ produce interference. The ratio of maximum and minimum intensities will be:

    (A) $10 : 8$

    (B) $9 : 1$

    (C) $4 : 1$

    (D) $2 : 1$

83. A soap bubble appears colored in sunlight due to: [BSEB 2025]

    (A) Dispersion

    (B) Scattering

    (C) Interference

    (D) Polarization

84. When the distance between the source of light and the screen is increased, the fringe width: [BSEB 2023]

    (A) Increases

    (B) Decreases

    (C) Remains unchanged

    (D) None of these

85. The phenomenon of interference is based on:

    (A) Phase difference

    (B) Amplitude change

    (C) Velocity change

    (D) Intensity change

86. The value of maximum resultant amplitude produced by the interference of two waves represented by $y_1 = 4 \sin \omega t$ and $y_2 = 3 \cos \omega t$ is: [BSEB 2023]

    (A) 7

    (B) 5

    (C) 1

    (D) 25

87. In which of the following physical quantities does redistribution occur in the interference of light? [BSEB 2021]

    (A) Frequency

    (B) Intensity

    (C) Wavelength

    (D) Speed

88. For constructive interference, the path difference between waves should be: [BSEB 2021]

    (A) $n\lambda$

    (B) $(2n + 1)\lambda/2$

    (C) $(n + 1)\lambda$

    (D) $n\lambda/2$

89. The formula for fringe width $(\beta)$ of interference is: [BSEB 2020]

    (A) $\beta = \frac{\lambda D}{d}$

    (B) $\beta = \frac{d}{D\lambda}$

    (C) $\beta = \frac{D \lambda}{d}$

    (D) $\beta = d.D.\lambda$

90. A thin oil layer appears colored due to: [BSEB 2019]

    (A) Diffraction

    (B) Interference

    (C) Polarization

    (D) Scattering

91. For destructive interference, the path difference should be: [BSEB 2026]

    (A) $n\lambda$

    (B) $(2n+1)\lambda/2$

    (C) Zero

    (D) Infinity

92. In Young’s double-slit experiment, if the width of the slits $(d)$ and the distance of the screen from the slits $(D)$ are both doubled, then the fringe width:

    (A) Will increase

    (B) Will decrease

    (C) Will remain unchanged

    (D) None of these

93. The phase difference $\phi$ is related to path difference $\Delta x$ by: [BSEB 2026]

    (A) $\Delta x = \frac{\lambda}{\pi} \phi$

    (B) $\Delta x = \frac{\pi}{\lambda} \phi$

    (C) $\Delta x = \frac{\lambda}{2\pi} \phi$

    (D) $\Delta x = \frac{2\pi}{\lambda} \phi$

94. On doubling the amplitude of a wave, its intensity:

    (A) Becomes double

    (B) Becomes four times

    (C) Remains half

    (D) Remains unchanged

95. In Young’s experiment, if $d$ is the distance between slits and $\lambda$ is wavelength, then angular width will be:

    (A) $d/\lambda$

    (B) $\lambda/d$

    (C) $\lambda \cdot d$

    (D) $1/\lambda d$

96. The phase difference between two waves $y_1 = a_1 \sin \omega t$ and $y_2 = a_2 \cos \omega t$ is:

    (A) $\pi/2$

    (B) $\pi$

    (C) 0

    (D) $2\pi$

97. In Young’s double-slit experiment, the maximum intensity is $I_0$. If one slit is closed, the intensity will become:

    (A) $I_0$

    (B) $I_0 / 2$

    (C) $I_0 / 4$

    (D) Zero

98. In the experiment of Biprism, if the wavelength of light is increased, the fringe width:

    (A) Increases

    (B) Decreases

    (C) Remains same

    (D) Becomes zero

99. Two coherent monochromatic light beams with intensities in the ratio $4 : 1$ are superimposed. The ratio of maximum and minimum intensities is:

    (A) $5 : 1$

    (B) $5 : 3$

    (C) $3 : 1$

    (D) $9 : 1$

100. The reason for color in a thin film is: [BSEB 2015]

     (A) Scattering

     (B) Interference

     (C) Dispersion

     (D) Diffraction

101. In Lloyd’s Mirror experiment, the central fringe is:

     (A) Bright

     (B) Dark

     (C) Colored

     (D) None of these

102. For interference, it is necessary that both sources are:

     (A) Coherent

     (B) Of different frequencies

     (C) Of different amplitudes

     (D) None of these

103. The interference phenomenon is based on which principle?

     (A) Law of conservation of energy

     (B) Law of conservation of momentum

     (C) Law of conservation of mass

     (D) Law of conservation of charge

104. In an interference pattern, energy:

     (A) Is destroyed

     (B) Is created

     (C) Is redistributed

     (D) None of these

Topic 8: Diffraction of Light

105. The width of diffraction fringes compared to interference fringes: [BSEB 2023]

     (A) Is equal

     (B) Is not equal

     (C) Is similar

     (D) None of these

106. Bending of light from the corners of an obstacle is called: [BSEB 2022]

     (A) Refraction

     (B) Diffraction

     (C) Interference

     (D) Reflection

107. The intensity of diffraction fringes:

     (A) Is same for all fringes

     (B) Decreases with distance from central fringe

     (C) Increases with distance from central fringe

     (D) Is irregular

108. Diffraction fringes obtained from a sharp straight edge:

     (A) Are of equal width

     (B) Are not of equal width

     (C) Are formed in the geometrical shadow

     (D) None of these statements is true

109. To observe the phenomenon of diffraction, the size of the obstacle should be:

     (A) Very large

     (B) Very small

     (C) Of the order of the wavelength of light

     (D) None of these

110. In Fresnel diffraction, the light source is at what distance from the obstacle?

     (A) Infinity

     (B) Finite distance

     (C) Very large distance

     (D) None of these

     [Image comparing Fresnel and Fraunhofer diffraction patterns and setups]

111. In Fraunhofer diffraction, the wavefront is:

     (A) Spherical

     (B) Cylindrical

     (C) Planar

     (D) None of these

112. The width of the central maximum in single-slit diffraction is:

     (A) $2\lambda D/e$

     (B) $\lambda D/e$

     (C) $2e/\lambda D$

     (D) $e/\lambda D$

113. The phenomenon of diffraction can be observed in:

     (A) Only light waves

     (B) Only sound waves

     (C) All types of waves

     (D) Only electromagnetic waves

Topic 9: Polarization of Light

114. Which is used to produce polarized light? [BSEB 2023]

     (A) Flint glass prism

     (B) NaCl prism

     (C) Nicol prism

     (D) Biprism

115. The phenomenon that proves the transverse wave nature of light is: [BSEB 2026]

     (A) Interference

     (B) Diffraction

     (C) Polarization

     (D) Reflection

116. Brewster’s Law is: [BSEB 2019]

     (A) $\mu = \sin i_p$

     (B) $\mu = \cos i_p$

     (C) $\mu = \tan i_p$

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

117. In plane polarized light, vibrations are:

     (A) Equal in all directions

     (B) Only in one direction

     (C) In mutually perpendicular directions

     (D) None of these

118. A ray of light is incident on a glass plate at an angle of $60^\circ$. If the reflected and refracted rays are mutually perpendicular, the refractive index of the material is:

     (A) $\sqrt{3}/2$

     (B) $\sqrt{3}$

     (C) $1/\sqrt{3}$

     (D) $1/2$

119. Which of the following cannot be polarized? [BSEB 2025]

     (A) Sound waves

     (B) Light waves

     (C) Radio waves

     (D) X-rays

120. The angle between the plane of vibration and the plane of polarization in polarized light is: [BSEB 2025]

     (A) $0^\circ$

     (B) $45^\circ$

     (C) $90^\circ$

     (D) $180^\circ$

121. Polaroid is used for:

     (A) Increasing intensity of light

     (B) Polarization of light

     (C) Reducing glare in glasses

     (D) Both (B) and (C)

122. Malus’ Law is:

     (A) $I = I_0 \cos \theta$

     (B) $I = I_0 \cos^2 \theta$

     (C) $I = I_0 \sin \theta$

     (D) $I = I_0 \tan \theta$

123. Nicol prism is based on:

     (A) Interference

     (B) Diffraction

     (C) Double Refraction

     (D) Reflection

124. The intensity of unpolarized light is $I_0$. After passing through an ideal polaroid, the intensity of transmitted light will be:

     (A) $I_0$

     (B) $I_0 / 2$

     (C) $I_0 / 4$

     (D) Zero

125. The phenomenon of polarization occurs only in:

     (A) Transverse waves

     (B) Longitudinal waves

     (C) Both

     (D) Neither

126. Natural light from the sun is: [BSEB 2026]

     (A) Polarized

     (B) Unpolarized

     (C) Partially polarized

     (D) Linearly polarized

127. Which of the following gives plane polarized light by selective absorption?

     (A) Quartz crystal

     (B) Polaroid

     (C) Tourmaline crystal

     (D) Both ‘B’ and ‘C’

Topic 10: Modern Physics & Miscellaneous

128. Which of the following shows the ‘particle’ nature of light?

     (A) Interference

     (B) Diffraction

     (C) Photoelectric effect

     (D) Polarization

129. The age of fossils is determined by: [BSEB 2017]

     (A) Carbon dating

     (B) X-ray

     (C) Gamma ray

     (D) Laser

130. Light is made of which type of vibrations?

     (A) Ether particles

     (B) Air particles

     (C) Electric and Magnetic fields

     (D) None of these

131. For laser action, what is necessary? [BSEB 2023]

     (A) High temperature

     (B) Semiconductor

     (C) High pressure

     (D) Population Inversion

132. The proponent of the corpuscular theory of light was:

     (A) Huygens

     (B) Newton

     (C) Fresnel

     (D) Maxwell

133. According to Newton, the velocity of light:

     (A) Is more in water than in air

     (B) Is less in water than in air

     (C) Is same in air and water

     (D) Is more in vacuum than in water

134. Which relation is correct for mass and energy? [BSEB 2022]

     (A) $m = E$

     (B) $m^2 = E$

     (C) $mc^2 = E$

     (D) $m = \sqrt{E/2}$

135. Which of the following cannot be explained by the wave theory of light? [BSEB 2018]

     (A) Reflection

     (B) Refraction

     (C) Photoelectric effect

     (D) Polarization

136. Electron volt (eV) is the unit of:

     (A) Energy

     (B) Potential

     (C) Velocity

     (D) Angular momentum

137. The reason for solar energy is:

     (A) Nuclear fission

     (B) Nuclear fusion

     (C) Chemical reaction

     (D) None of these

138. The rest mass of a photon is:

     (A) Zero

     (B) Infinite

     (C) $9.1 \times 10^{-31} \text{ kg}$

     (D) None of these

139. The energy of a photon of wavelength $\lambda$ is:

     (A) $hc\lambda$

     (B) $hc/\lambda$

     (C) $h\lambda/c$

     (D) $\lambda/hc$

Topic 11: Mixed Revision Questions

140. The inverse square law for intensity of light ($I \propto 1/r^2$) is valid for: [BSEB 2026]

     (A) Point source

     (B) Linear source

     (C) Cylindrical source

     (D) Planar source

141. The relation between resolving limit and resolving power is:

     (A) Directly proportional

     (B) Inversely proportional

     (C) Equal

     (D) No relation

142. The refractive index of glass is minimum for which color?

     (A) Violet

     (B) Blue

     (C) Green

     (D) Red

143. The wave number is equal to:

     (A) $1/\lambda$

     (B) $\lambda$

     (C) $2\pi/\lambda$

     (D) $\lambda/2\pi$

144. If $c$ is the speed of light in vacuum and $v$ is the speed in a medium, then refractive index $\mu$ will be:

     (A) $v/c$

     (B) $c/v$

     (C) $c \times v$

     (D) $1/cv$

145. The focal length of a convex lens is 25 cm. Its power is:

     (A) 4D

     (B) 2D

     (C) 0.25D

     (D) 25D

146. In an astronomical telescope, the aperture of the objective is:

     (A) Large

     (B) Small

     (C) Equal to eye-piece

     (D) None

147. The path difference for constructive interference is:

     (A) $n\lambda$

     (B) $(2n+1)\lambda/2$

     (C) Zero

     (D) Both A and C

148. Light waves are transverse because they show:

     (A) Reflection

     (B) Interference

     (C) Diffraction

     (D) Polarization

149. For a healthy eye, the focal length of the eye lens is adjusted by:

     (A) Iris

     (B) Ciliary muscles

     (C) Cornea

     (D) Pupil

150. The wavelength of light is related to its color. Which color has the longest wavelength?

     (A) Violet

     (B) Blue

     (C) Red

     (D) Yellow