Light

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1. Sun appears red in colour during sunrise and sunset due to
(A) The fact that sun emits only red colour at that time
(B) Red light having longer wavelength scatters away
(C) The sun comes out of the mountains
(D) The fact that all other colours scatter away except red
Ans. (D)

2. The colour of the ocean appears to be blue
because the sunlight falling on it is
(A) Reflected (B) Refracted
(C) Diffracted (D) Scattered
Ans. (D)

3. In the absence of the earth’s atmosphere sky would appear
(A) Blue (B) Deep Red
(C) White (D) Black
Ans. (D)

4. Which is the phenomenon that established the
transverse nature of light?
(A) Reflection (B) Refraction
(C) Diffraction (D) Polarization
Ans. (D)

5. Rainbows are formed when sunlight
(A) Incident on rain drops hanging in the atmosphere
is dispersed after suffering refraction
(B) Incident on rain drops hanging in the
atmosphere is dispersed after suffering
refraction and internal reflection.
(C) Incident on raindrops hanging in the
atmosphere is dispensed after suffering reflection
(D) None of the given statement is correct
Ans. (B)

6. Which of the following colour of light deviates least through the prism?
(A) Yellow (B) Green
(C) Violet (D) Red
Ans. (D)

7. Rainbow is formed due to
(A) Refraction and Dispersion
(B) Scattering and Refraction
(C) Diffraction and Refraction
(D) Reflection and Refraction
Ans. (D)

8. Which of these waves can be polarized
(A) Sound waves in air
(B) Longitudinal waves on a string
(C) Transverse waves on a string
(D) Lightwaves
Ans. (D)

9. The sky appears blue due to
(A) Rayleigh scattering (B) Mie scattering
(C) Backscattering (D) None of the above
Ans. (A)

10. The splitting of white light into its component is due to
(A) Reflection (B) Refraction
(C) Transmission (D) Dispersion
Ans. (D)

11. Light scattering takes place in
(A) Colloidal solutions (B) Acidic solutions
(C) Electrolyte solutions (D) Basic solutions
Ans. (A)

12. Which of the following statements is true when we see ‘rainbow’?
(A) We face sun and raindrops
(B) The sun remains behind as and we face raindrops
(C) In light rainfall, we face sun
(D) The sky remains clear and the sun is at lower
position in the sky
Ans. (B)

13. A soap bubble shows colours when illuminated
with white light. The is due to
(A) Diffraction (B) Polarisation
(C) Interference (D) Reflection
Ans.(C)

14. The formation of the Rainbow takes place, when sunlight–
(A) Scattered due to the reflection from water
drops in atmosphere
(B) Scattered due to refraction from water drops
in atmosphere
(C) Scattered due to refraction and total internal
reflection from water drops
(D) None of the above
Ans. (C)

15. The Rainbow has: (Chose incorrect Statement)
(A) Violet light as its innermost colour towards earth
(B) Its curvature bends towards earth
(C) Red light as its outermost colour toward sky
(D) Red light as its innermost colour towards earth
Ans. (D)

16. On a rainy day small oily films on water shows
brilliant colour. This is due to –
(A) Scattering (B) Dispersion
(C) Interference (D) Polarization
Ans.(C)

17. An optically plane surface reflects a beam of light
(A) As a parallel beam in one direction
(B) As diffused beams in all directions
(C) As parallel beams in all direction
(D) As a diffused beam in one direction
Ans. (A)

18. Which one of the following reflects back more
sunlight as compared to other three?
(A) Sand desert
(B) Land covered with fresh snow
(C) Prairie land (D) Paddy crop land
Ans. (B)

19. Purpose of an optical fibre is to
(A) Reflect light of different colours
(B) Dispense light into component colours
(C) Refract light of different colours
(D) Transmit light of different colours
Ans. (D)

20. The Phenomenon which causes mirage is
(A) Interference (B) Diffraction
(C) Polarization (D) Total Internal Reflection
Ans. (D)

21. Total Internal Reflection can not take place
when light goes from
(A) Water to Glass (B) Glass to water
(C) Water to air (D) Glass to air
Ans. (A)

22. Optical fibre works on the principle of
(A) Refraction (B) Scattering
(C) Interference
(D) Total Internal Reflection
Ans. (D)

23. Energy in reflected light is
(A) Does not depend on the angle of incidence
(B) Increases with increase in angle
(C) Decrease with increase in angle incidence
(D) Become maximum for an angle of incidence of 45°
Ans. (B)

24. Which of the following optical phenomena is
responsible for the brilliance of diamond?
(A) Maximum Refraction
(B) Total Internal Reflection
(C) Total surface Reflection
(D) 100% transmission
Ans. (B)

25. The phenomenon of change in direction of light
when it passes from one medium to another is called
(A) Propagation (B) Reflection
(C) Refraction (D) Dispersion
Ans. (C)

26. Which of the following is not caused by
atmospheric refraction?
(A) Sun appearing red at sunset
(B) Twinkling of stars at night
(C) Sun appearing higher in the sky than it actually is
(D) Sun becoming visible two or three minutes before actual sunrise.
Ans. (A)

27. A star appears twinkling in the sky because of
(A) Scattering of light by the atmosphere
(B) Reflection of light by the atmosphere
(C) Refraction of light by atmosphere
(D) Diffraction of light by atmosphere
Ans. (C)

28. A water tank appears shallower when it is
viewed from top due to
(A) Rectilinear propagation of light
(B) Reflection
(C) Total Internal Reflection
(D) Refraction
Ans. (D)

29. The reason for a swimming pool to appear less
deep than the actual depth is
(A) Refraction (B) Light scattering
(C) Reflection (D) Interference
Ans. (A)

30. A plane glass slab is kept over coloured letters
which appears least raised is –
(A) Red (B) Green
(C) Violet (D) Blue
Ans. (C)

31. Lens is made up of
(A) Pyrex glass (B) Flint glass
(C) Ordinary glass (D) Cobalt glass
Ans. (B)

32. For a person having hypermetropia, the near point is
(A) Greater than 25 cm (B) Greater than 50 cm
(C) Less than 25 cm (D) Infinity
Ans. (C)

33. The head mirror used by ENT doctors is
(A) Concave (B) Convex
(C) Plane (D) Plano-convex
Ans. (A)

34. Vehicles use ____ to see the objects coming from behind
(A) Concave Lens (B) Convex Lens
(C) Concave Mirror (D) Convex Mirror
Ans. (D)

35. What is a compound microscope
(A) A microscope that has one lens
(B) A microscope that has two set of lenses
(C) A microscope whose lenses are concave
(D) A microscope whose lenses are convex
Ans. (D)

36. Convex mirrors are used as a rear view mirror
in motor cycles because
(A) It forms real image (B) It forms erect image
(C) It forms smaller image as compared with object
(D) All of the above
Ans. (D)

37. Persons suffering from myopia are advised to use
(A) Convex lens (B) Concave lens
(C) Plano-concave lens (D) Plano-convex lens
Ans. (B)

38. Magnifying Glass is basically a
(A) Plano-concave lens (B) Cancave lens
(C) Convex lens (D) Cylindrical lens
Ans. (C)

39. Shaving Mirror is
(A) Convex (B) Concave
(C) Plane (D) Parabolic
Ans. (B)

40. Which type of mirror is used in the head lights of vehicles
(A) Plane Mirror (B) Concave Mirror
(C) Convex Mirror (D) Parabolic Mirror
Ans. (B)

41. Electron Microscope is more magnifier than
light magnifying because
(A) Velocity of electron is less than velocity of light
(B) Wavelength of electron is less than the
wavelength of light
(C) Electron contains more energy than particles
(D) More powerful lenses are used in electron
Microscope
Ans. (D)

42. A periscope works on the principle of
(A) Refraction (B) Total Internal Reflection
(C) Diffraction (D) Reflection
Ans. (D)

43. In mirrors the back surface is painted with a thin layer of
(A) Mercury (B) Silver
(C) Red oxide (D) Silver Nitrate
Ans. (B)

44. Find the power of a convex lens if the image formed
is at a distance of 10 cm from the lens when the
object is placed on the other side of the lens at 40cm from the optical centre?
(A) 12.5 dioptre (B) 7.5 dioptre
(C) –12.5 dioptre (D) –7.5 dioptre
Ans.(A)

45. Find the power of a convex lens if the image formed
is at a distance of 20 cm from the lens when the object is placed on the other side of the lens at 60
cm from the optical centre?
(A) 3.33 dioptre (B) 6.67 dioptre
(C) -6.67 diopre (D) -3.33 dioptre
Ans. (B)

46. Find the power of a convex lens if the image
formed is at a distance of 20 cm from the lens
when the object is placed on the other side of
the lens at 25 cm from the optical centre?
(A) 1 dioptre (B) – 9 dioptre
(C) 9 dioptre (D) 1 dioptre
Ans. (C)

47. Which of the following is used to split white
light into different colours?
(A) Glass slab (B) Convex lens
(C) Concave lens (D) Prism
Ans. (D)

48. Spectacles used for viewing 3D films have
(A) Bifocal lens (B) Convex lens
(C) Concave lens (D) Polaroids
Ans. (D)

49. A concave lens always form an image which is
(A) Real and erect (B) Virtual and erect
(C) Real and inverted (D) Virtual and inverted
Ans. (B)

50. One can distinguish a telescope from a microscope by observing
(A) Length (B) Colour
(C) Size of the lens
(D) length and size of the lens
Ans. (C)

51. To get the magnified and virtual image mirror is used–
(A) Plane Mirror (B) Convex Mirror
(C) Concave Mirror (D) Concave Lens
Ans. (C)

52. Which of the following always makes the smaller
image of body, which is placed in front of it?
(A) Plane Mirror (B) Convex Mirror
(C) Convex Lens (D) Concave Mirror
Ans. (B)

53. The Image formed by specific mirror; legs appears
as of same size but head and his body appears
smaller than its real size, when person stands in
front of mirror. What is the nature of mirror?
(A) Plane and Concave (B) Convex and Concave
(C) Convex and Plane (D) Plane
Ans. (C)

54. What is a zoom lens?
(A) A lens with a definite focal length
(B) A lens with a transitional focal length
(C) It is used in Radio Telescopes.
(D) None of these
Ans. (B)

55. Dioptre is the unit of–
(A) Power of lens (B) Focal length of lens
(C) Intensity of lens (D) Intensity of sound
Ans. (A)

56. Radio telescopes are better than optical telescopes because–
(A) They can detect faint galaxies which cannot
be done by optical telescope.
(B) They can even work in cloudy conditions.
(C) They can work during day and night
(D) All of the above.
Ans. (D)

57. To eliminate the glare of headlight in motorcars–
(A) Polaroid’s are used (B) Glass prism are used
(C) Thin films are used (D) Filters are used.
Ans. (A)

58. The outer white part of the eye that protects
the inner structures is____.
(A) Iris (B) Sclera
(C) Retina (D) Cornea
Ans. (B)

59. Person who is color blind can not distinguish between
(A) Black and yellow (B) Red and green
(C) Yellow and white (D) Green and blue
Ans. (B)

60. The least distance of distinct Vision is
(A) 35 cm (B) 25 cm
(C) 45 cm (D) 15 cm
Ans. (B)

61. Distant objects are visible as little out of focus
in the condition
(A) Presbyopia (B) Hypermetropia
(C) Astigmatism (D) Myopia
Ans. (D)

62. Sensitivity of human eye is maximum in the
(A) Violet region (B) Green region
(C) Blue region (D) Red region
Ans. (B)

63. A man can not see clearly beyond 10 meters.
The disease he suffers from.
(A) Far sight (B) Myopia
(C) Cataract (D) Hypermetropia
Ans. (B)

64. The part of the eye having largest refractive index is
(A) Cornea (B) Aqueous humor
(C) Lens (D) Virtuous humor
Ans. (C)

65. Hypermetropia or long sightedness can be corrected by using
(A) Bifocal lenses (B) Cylindrical lenses
(C) Concave lenses (D) Convex lenses
Ans. (D)

66. The final image in a simple microscope is
(A) Real, diminished and inverted
(B) Real, magnified and erect
(C) Virtual, magnified and erect
(D) Virtual, diminished and erect
Ans. (C)

67. Is dangerous to observe solar eclipse with naked eyes because
(A) Infrared radiations from sun burn our retina
(B) Ultraviolet radiations from sun burn our retina
(C) All radiations from sun initiate chemical reactions in eyes
(D) Cosmic rays reach eyes more during the eclipse
Ans. (B)

74. Protanopia is a kind of colourblindness, in which
defected person can’t see the colour –
(A) Green (B) Red
(C) Blue (D) All of these
Ans. (D)

75. The Plate of Blue glass appears blue in sunlight because–
(A) It absorb the blue light
(B) It transmits the blue light
(C) It absorbs all the colours including blue
(D) Transmits all the colours including blue.
Ans. (B)

76. The speed of light in air is
(A) 3 × 108 m/s (B) 3 × 10–8 m/s
(C) 3 × 103 m/s (D) Infinity
Ans. (A)

77. Photon is the fundamental unit/quantum of
(A) Gravitation (B) Electricity
(C) Magnetism (D) Light
Ans. (D)

78. Light beam which is highly directional is called
(A) Eraser (B) Grazer
(C) Maser (D) Laser
Ans. (D)

79. Persistence of vision is the principle behind
(A) Binocular (B) Camera
(C) Periscope (D) Cinema
Ans. (D)

80. Which of the following is responsible for the
working of newton’s colour disc experiment
(A) Formation of pure spectra
(B) Formation of impure spectra
(C) Persistence of vision
(D) Principle of complementary colour
Ans. (C)

68. Short-sight in human eye can be corrected by using proper
(A) Convex lens (B) Concave lens
(C) Cylindrical lens (D) Bifocal lens
Ans. (B)

69. Myopia is the same as
(A) Near sightedness (B) Astigmatism
(C) Presbyopia (D) Long sightedness
Ans. (A)

70. The owl can see most clearly in total darkness because
(A) It has squint eyes
(B) It has large eyes with rods directed forward,
giving it binocular sight
(C) It has light bulbs in its eyes provided by nature
(D) It produces infrasonic sounds
Ans. (B)

71. What is myopia?
(A) Inability to see distant objects clearly
(B) Abnormal functioning of the thyroid gland
(C) It is a condition of enlargement of heart
(D) It is a kidney disorder
Ans. (A)

72. The Sky appears to an astronaut–
(A) White (B) Bark Blue
(C) Light Green (D) Black
Ans. (D)

73. Colour blindness defect can be corrected by using the lens–
(A) Concave Lens (B) Convex Lens
(C) Cylindrical lens (D) None of these
Ans. (D)

81. Solar cells work on the principle of
(A) Photovoltaic effect (B) Photoelectric effect
(C) Photoconductive effect
(D) Photosynthesis
Ans. (A)

82. A light-year is a unit of
(A) Time (B) Distance
(C) Speed of light (D) Intensity of light
Ans. (B)

83. Ozone layer above the surface of Earth provides
a shield against
(A) X-rays (B) Ultra Violet Rays
(C) Gamma Rays (D) Infrared Rays
Ans. (B)

84. The primary colours in photography are
(A) Red, Blue, Yellow (B) Red, Yellow, Green
(C) Red, Blue, Green (D) Blue, Yellow, Green
Ans. (C)

85. Which of the following is not a part of a CRT?
(A) Phosphor Screen (B) Shadow Mask
(C) Electron Gun (D) Gas Plasma
Ans. (D)

86. Light travels fastest in
(A) Nitrogen (B) Air
(C) Steel (D) Vacuum
Ans. (D)

87. Who Invented Laser?
(A) William FrieseGreene
(B) Arthur Fry
(C) Gordon Gould (D) Otto von Guericke
Ans. (C)

88. Who Invented LED?
(A) Nick Holonyak (B) Elias Howe
(C) Chuck Hull (D) Christiaan Huygens
Ans. (A)

89. Instrument for measuring blueness of the sky
or ocean is called ___________.
(A) Bathymeter (B) Ceraunograph
(C) Cyanometer (D) Barometer
Ans. (C)

90. Lumen is a unit of –
(A) Luminous Flux (B) Luminous Intensity
(C) Luminous density (D) Brightness
Ans. (A)

91. White Light constitutes the colours –
(A) 4 (B) 5
(C) 6 (D) 7
Ans. (D)

92. Atomic clock transitions depends upon the –
(A) Sodium (B) Caesium
(C) Magnesium (D) Aluminum
Ans. (B)

93. The photoelectric effect is described as the ejection
of electrons from the surface of a metal when –
(A) It is heated
(B) It is placed in the strong electric field.
(C) Electron of suitable velocity impinge on it.
(D) Light of suitable wavelength falls on it.
Ans. (D)

94. Which of the following gase is used in the Yellowish lamps used as street Lights?
(A) Sodium (B) Neon
(C) Hydrogen (D) Nitrogen
Ans. (B)

95. Photo oxidation process is initiated by –
(A) Light (B) Heat
(C) Oxygen (D) Catalyst
Ans. (A)

96. What is a Hologram?
(A) Graphical Representation of frequency distribution
(B) 3D– MRI
(C) A 3D Shadow to reproduce the photographic record
(D) A Liquid Crystal Display
Ans. (C)

97. Who invented the optical fibre?
(A) Samuel Cohen (B) Narinder Kapany
(C) Percy Spencer (D) T.H. Maimah
Ans. (B)

98. Which of the following purpose optical fibre is used for?
(A) Weaving (B) Musical Instrument
(C) Eye Surgery (D) Communication
Ans. (D)

99. Sir C.V. Raman is awarded by Nobel Prize for
his experiment of –
(A) Reflection of Light (B) Dispersion of Light
(C) Scattering of Light (D) Diffraction of Light
Ans. (C)

100. Light Waves are –
(A) Electric Wave (B) Magnetic Wave
(C) Electromagnetic Wave
(D) Electrostatic Wave
Ans. (C)

101. Time taken by the Sun Light to reach the earth?
(A) 5.5 min. (B) 6.8 min.
(C) 8.3 min. (D) 9.5 min.
Ans. (C)

102. The speed of light with the rise in the temperature of the medium:
(A) Increases (B) Decreases
(C) Remains unaltered (D) Drops suddenly
Ans. (C)

103. Who measured the velocity of light first?
(A) Galileo (B) Newton
(C) Romer (D) Einstein
Ans. (C)

104. Which colour is the complementary colour of yellow?
(A) Blue (B) Green
(C) Orange (D) Red
Ans. (A)

105. Ability to distinguish two closely placed objects is ______.
(A) Resolving power (B) Video power
(C) Distinguish power (D) Magnifying power
Ans. (A)

106. Which of the following phenomena is involved
in Kaleidoscope?
(A) Refraction (B) Reflection
(C) Total Internal reflection
(D) Diffraction
Ans. (B)

107. In a magnifying glass ______ lens is used.
(A) Convex (B) Concave
(C) Plano concave (D) Plano convex
Ans. (A)

108. When an object is kept between two parallel
plane mirrors then what is the number of
images formed?
(A) 1 (B) 2
(C) 4 (D) Infinite
Ans. (D)

109. A _____ splits sunlight into seven colours.
(A) Concave lens (B) Convex lens
(C) Prism (D) Concave mirror
Ans. (C)

110. Which type of mirror is used by dentists to see
large images of teeth?
(A) Concave mirror (B) Convex mirror
(C) Plane mirror (D) Cylindrical mirror
Ans. (A)

111. According to law of reflection:
(A) Angle of incidence is greater than angle of
reflection
(B) Angle of incidence is smaller than angle of
reflection
(C) Angle of incidence is always equal to angle of
reflection
(D) Both angles are always unequal
Ans. (C)

112. Who invented first working laser?
(A) A. H. Taylor (B) W. K. Roentgen
(C) T. H. Maiman (D) Fred Morrission
Ans. (C)

113. Reflection from a smooth surface like that of a
mirror is called ___________ reflection.
(A) Regular (B) Irregular
(C) Diffused (D) Fused
Ans. (A)

114. Why does a black board appears black in colour?
(A) It reflects black colour
(B) It absorbs black colour
(C) It reflects all colours
(D) It absorbs all the colours
Ans. (D)

115. The bending of light when it passes around a
corner or a slit is due to ______.
(A) Reflection (B) Refraction
(C) Diffraction (D) Total internal reflection
Ans. (C)

116. What is the reason for formation of Mirage in desert?
(A) Refraction of light
(B) Reflection of light
(C) Total internal reflection of light
(D) Both Refraction and Total internal reflection
of light
Ans. (D)

117. Speed of light is maximum in _____.
(A) Vacuum (B) Solids
(C) Liquids (D) Gases
Ans. (A)

118. Convex mirror is generally used in _____.
(A) Solar cookers (B) Ophthalmoscope
(C) Reflector for head light
(D) Rear view mirror
Ans. (D)

119. If objects appear enlarged and inverted in a
rear view mirror, then which type of mirror is used?
(A) Concave (B) Convex
(C) Cylindrical (D) Plane
Ans. (A)

120. Why does water tank appear shallower when
viewed from the top?
(A) Due to reflection (B) Due to refraction
(C) Due to diffraction
(D) Due to total internal reflection
Ans. (B)

121. Which colour is formed when Red and Green are mixed?
(A) Light blue (B) Yellow
(C) White (D) Grey
Ans. (B)

122. Which phenomena shows the particle nature of light?
(A) Diffraction (B) Interference
(C) Photoelectric effect (D) Polarisation
Ans. (C)

123. Which colour is formed when Blue and Green are mixed?
(A) Cyan (B) Brown
(C) Black (D) Violet
Ans. (A)

124. Optical fibre works on which of the following
principle of light?
(A) Reflection (B) Refraction
(C) Diffraction (D) Total internal reflection
Ans. (D)

125. When light passes from one medium to another,
this phenomenon of change in its direction is called _____.
(A) Refraction (B) Diffraction
(C) Propagation (D) No option is correct
Ans. (A)

126. The side mirrors of vehicles are of which type of mirrors?
(A) Convex (B) Concave
(C) Plane (D) Inverted
Ans. (A)

127. An image formed by a plane mirror, that cannot
be obtained on a screen is called _______.
(A) Virtual image (B) Real image
(C) Inverted image (D) Erect image
Ans. (A)

128. The impression of an image persists on the
retina for about _________ of a second.
(A) 1/10th (B) 1/8th
(C) 1/16th (D) 1/5th
Ans. (C)

129. An image formed by a concave mirror on a screen is called __________?
(A) Virtual image (B) Real image
(C) Inverted image (D) Erect image
Ans. (B)

130. The incident ray, the _________ at the point of
incidence and the reflected ray all lie in the
same plane.
(A) Surface (B) Tangent
(C) Normal (D) Angle of reflection
Ans. (C)

131. The reflection formed by the plane mirror is________________.
(A) Vertical inversion (B) A real image
(C) Lateral inversion (D) An enlarged image
Ans. (C)

132. Convex and concave mirrors are examples of?
(A) Plane mirrors (B) Spherical mirrors
(C) Inverted mirror (D) Erect mirror
Ans. (B)

133. The angle between the __________and the
incident ray is called the angle of incidence.
(A) Surface (B) Normal
(C) Tangent (D) Reflected ray
Ans. (B)

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