Answered 0 of 25 on this page · Correct 0 · Wrong 0
Q51. Diffusion of light in the atmosphere is due to the following:
- Acarbon dioxide
- Bdust particles
- Chelium
- Dnone of these
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Answer: B) dust particles
Q52. An observer on the lunar surface will see the sky during the daytime as-
- Alight yellow
- BBlue
- Corange
- DBlack
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Answer: D) Black
Q53. A spherical air bubble is embedded in a piece of glass. How does the bubble behave for a ray of light passing through it?
- Aplane diverging lens
- BDiverging lens
- Cplane converging lens
- Dconverging lens
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Answer: B) Diverging lens
Q54. Red light is used in traffic signals because-
- AThe color of blood is red
- BAnimals can detect the color red
- CRed colour is least dispersed
- DRed symbolizes danger
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Answer: C) Red colour is least dispersed
Q55. The sea appears blue
- ADue to the greater depth
- BDue to reflection from the sky and scattering of light by water particles
- CDue to the blue colour of the water
- Ddue to the surface of the water
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Answer: B) Due to reflection from the sky and scattering of light by water particles
Q56. Why does the atmosphere turn red at sunrise and sunset?
- Arefraction of light
- Breflection of light
- Cdispersion of light
- Dscattering of light
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Answer: D) scattering of light
Q57. Which colour is dispersion more in rainbow?
- APurple
- BYellow
- CRed
- DBlue
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Answer: A) Purple
Q58. The stars appear higher in the sky than they actually are. What can explain this?
- Aatmospheric refraction
- BDispersion of light
- Ctotal internal reflection
- DDiffraction of light
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Answer: A) atmospheric refraction
Q59. Why does dry sand appear shiny, while wet sand is dull?
- Ait's an optical illusion
- BThis is because of reflection
- CThis is due to refraction
- DThis is due to scattering
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Answer: B) This is because of reflection
Q60. Which one of the following is used in making periscope?
- Aconcave lens
- Bconcave mirror
- Cplane mirror
- DNone of these
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Answer: C) plane mirror
Q61. The formation of bright colours in thin soap foam is the result of which phenomenon?
- AMultiple reflection and interference
- BMultiple refraction and dispersion
- CRefraction and Dispersion
- DPolarization and interference
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Answer: A) Multiple reflection and interference
Q62. What do vehicles use to see objects coming from behind?
- AConvex lacing
- Bconcave lens
- Cconvex mirror
- Dconcave mirror
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Answer: C) convex mirror
Q63. Which of the following is not a result of atmospheric refraction?
- Athe sun appearing two or three minutes before its actual sunrise
- Bthe sun appears red at sunset
- CThe sun appears higher in the sky than its actual height
- Dtwinkling stars at night
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Answer: B) the sun appears red at sunset
Q64. The mirror used by dentists to examine patients' teeth is
- AConvex
- Bconcave
- Ceven
- DNone of these
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Answer: B) concave
Q65. Which type of mirror is used in the headlights of vehicles?
- Aplane mirror
- Bconvex mirror
- Cconcave mirror
- DParabolic mirror
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Answer: D) Parabolic mirror
Q66. Used for shaving-
- Aconcave mirror
- Bplane mirror
- Cconvex mirror
- Dnone of these
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Answer: A) concave mirror
Q67. Which of these is correct?
- A1/f=1/u=1/v
- Bf=D/2
- C1/f-1/u+1/v
- Df=u+v
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Answer: D) f=u+v
Q68. What is the part of the human eye on which the image is formed called?
- Apupil
- Bcornea
- Cretina
- DIris
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Answer: A) pupil
Q69. The image formed by the eye on the retina is-
- Areal, inverted, small
- Breal, upright, large
- Creal, straight, small
- Dunreal, inverted, small
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Answer: B) real, upright, large
Q70. The minimum height of a plane mirror to see the full image of a person is-
- Aequal to the height of the person
- Bhalf the person's height
- Cone-fourth the height of a person
- Dtwice the height of the person
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Answer: D) twice the height of the person
Q71. If an object is placed between two parallel plane mirrors, then the number of images formed is-
- A4
- B1
- C2
- Dinfinite
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Answer: B) 1
Q72. Two plane mirrors are placed at a 90° angle and a candle is burning between them. How many images of the candle will be formed in the mirrors?
- A2
- B3
- C4
- Dinfinity
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Answer: C) 4
Q73. When three images of an object are to be obtained with the help of plane mirrors, what should be the angle between the mirrors?
- A0°
- B60°
- C90°
- D45°
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Answer: C) 90°
Q74. If a person stands between two plane mirrors inclined at an angle of 60°, how many images will he see?
- A3
- B4
- C5
- D6
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Answer: C) 5
Q75. How many images will be formed by two mirrors inclined at 120° to each other?
- A4
- B3
- C2
- D1
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Answer: C) 2