# Optics – Old Year Questions

1. Which of the following radiations has the highest energy per quantum?

(a) 320-400 nm
(b) 200-280 nm
(c) 280-320 nm
(d) 400-600 nm

[Uttarakhand P.C.S. (Pre) 2012]

2. The visible range of solar radiation is-

(a) 100-400 nm
(b) 400-700 nm
(c) 740-10000 nm
(d) None of the above

[53rd to 55th B.P.S.C. (Pre) 2011]

3. The wavelength extension of visible light is –

(a) Between 200-900 nm
(b) Between 250-850 nm
(c) Between 300-800 nm
(d) Between 390-780 nm

[U.P.P.C.S.(Mains) 2005]

4. The wavelength of the visible spectrum is in the range :

(a) 1300 Å – 3900 Å
(b) 3900 Å – 7600 Å
(c) 7800 Å – 8200 Å
(d) 8500 Å – 9800 Å
(e) None of the above/More than one of the above

[63rd B.P.S.C. (Pre) 2017]

5. The human eye is most sensitive to visible light of the wavelength :

(a) 6050 Å
(b) 5500 Å
(c) 4500 Å
(d) 7500 Å

[U.P.P.S.C. (R.I.) 2014]

6. Among the colours mentioned below, the eye is most sensitive to colours between :

(a) Red and green
(b) Orange and yellow
(c) Green and blue
(d) Yellow and green

[U.P.P.C.S. (Mains) 2008]

7. Which of the following statements is not correct?

(a) The human ear becomes most sensitive at 1000 Hz.
(b) The human eye becomes most sensitive to red colour.
(c) Persistence of hearing is 1/10 second.
(d) Persistence of vision is 1/16 second.

[U.P. R.O./A.R.O. (Pre) 2021]

8. The nature of radiation of light is-

(a) Like wave
(b) Like particle
(c) Like both of wave and particle
(d) Like neither of wave nor of particle

[42nd B.P.S.C. (Pre) 1997-98]

9. Light appears to travel in a straight line because –

(a) It consists of small particles.
(b) The velocity of light is very large.
(c) The wavelength of light is very small.
(d) Light is reflected by the surroundings.

[U.P.P.S.C. (R.I.) 2014]

10. Which of the following statements is true?

(a) The light has a greater velocity.
(b) The sound has the greatest velocity.
(c) Celestial objects have the greatest velocity.
(d) Rocket has the greatest velocity.

U.P. Lower Sub. (Pre) 2002

11. The speed of light in a vacuum is near –

(a) 3 × 1010 metre/sec
(b) 3 × 108metre/sec
(c) 3 × 108km/sec
(d) 3 × 108light years

[43rd B.P.S.C. (Pre) 1999]

12. The speed of light is –

(a) 9×10² m/sec
(b) 3×1011 m/sec
(c) 3×108 m/sec
(d) 2×104 m/sec

[Jharkhand P.C.S. (Pre) 2003]

13. The speed of light in air depends on :

(a) Pressure
(b) Density
(c) It is independent of pressure, temperature and density
(d) Temperature

[Jharkhand P.C.S. (Pre) 2021]

14. Velocity of light is maximum in –

(a) Diamond
(b) Water
(c) Vacuum
(d) Hydrogen

[U.P.P.S.C. (R.I.) 2014]

15. The speed of light will be minimum while passing through–

(a) Glass
(b) Vacuum
(c) Water
(d) Air

[I.A.S. (Pre) 1994]

16. The time taken to reach the Sunlight up to the surface of earth is approximately –

(a) 4.2 sec
(b) 4.8 sec
(c) 8.5 minutes
(d) 3.6 hrs.

[42nd B.P.S.C. (Pre) 1997]

17. Light from the Sun reaches Earth in about :

(a) 2 minutes
(b) 4 minutes
(c) 8 minutes
(d) 16 minutes

[U.P.P.C.S. (Mains) 2006]

18. The sunlight from the sun to the earth reaches in :

(a) 5 minutes
(b) 6 minutes
(c) 8 minutes
(d) 10 minutes
(e) None of the above/More than one of the above

[65th B.P.S.C. (Pre) 2019]

19. Which of the following has the highest velocity?

(a) Cosmic rays
(b) Light
(c) Electron
(d) Supersonic wave

[U.P. P.C.S. (Pre) 2018]

20. Which of the following does not change when light travels from one medium to another?

(a) Velocity
(b) Wavelength
(c) Frequency
(d) Refractive index
(e) None of the above / More than one of the above

[66th B.P.S.C. (Pre) 2020]

21. When light waves pass from air to glass the variable affected are –

(a) Wavelength, frequency and velocity
(b) Velocity and frequency
(c) Wavelength and frequency
(d) Wavelength and velocity

[I.A.S. (Pre) 2001]

22. When light passes from one medium to another medium, which one of the following does not change :

(a) Intensity
(b) Velocity
(c) Wavelength
(d) Frequency

[U.P.P.C.S. (Mains) 2003]

23. When a ray of light travels from a denser medium to a rarer medium then

(a) It speeds up and bends away from the normal
(b) It speeds up and bends towards the normal
(c) It slows down and bends away from the normal
(d) It slows down and bends towards the normal

[Chattisgarh P.C.S. (Pre) 2018]

24. The formation of glittering colours in the thin foam of soap is the result of the following phenomenon –

(a) Total refection and interference
(b) Total refraction and dispersion
(c) Diffraction and dispersion
(d) Polarization and interference

[I.A.S. (Pre) 1993]

25. Total internal reflection can take place when light travels from :

(a) Diamond to glass
(b) Water to glass
(c) Air to water
(d) Air to glass

[I.A.S. (Pre) 1996]

26. A cut diamond shines brilliantly due to

(a) Some inherent property
(b) Total internal refection
(c) Its molecular structure
(d) Absorption of light

[U.P.P.C.S. (Pre) 2017, U.P.P.C.S. (Mains) 2015]

27. The diamond appears lustrous because of :

(a) Refection
(b) Refraction
(c) Total Internal Reflection
(d) Scattering

[U.P.P.C.S. (Mains) 2012, U.P.P.C.S. (Pre) 1996]

28. What is the reason behind the extraordinary shining of the diamond cuts in a proper way?

(a) Because it has a higher transparency
(b) Because it has a higher refractive index
(c) Because it is so hard
(d) Because it has a fixed deviation for

[I.A.S. (Pre) 1994]

29. Given below are two statements, one labelled as

Assertion (A) and other labeled as Reason (R) :
Assertion (A): A diamond sparkles more than a glass imitation cut to the same shape.
Reason (R): The refractive index of diamond is less than that of glass.

In the context of the above two statements, which one of the following is correct?

(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false.
(d) A is false but R is true.

[I.A.S. (Pre) 1995]

30. Optical fibre works on the principle of :

(a) Total internal reflection
(b) Refraction
(c) Scattering
(d) Interference

[U.P. U.D.A./L.D.A. (Pre) 2010, U.P.P.C.S. (Spl) (Pre) 2008, I.A.S. (Pre) 1995]

31. The phenomenon used in optical fber for transmission of light energy is

(a) Total internal refection
(b) Difraction
(c) Scattering
(d) Refraction

[U.P.P.C.S. (Pre) 2019]

32. Which one of the following phenomena is used in optical fibres?

(a) Interference
(b) Refraction
(c) Total internal refection
(d) Polarisation

[U.P.P.C.S. (Mains) 2015]

33. In fiber-optic communication, the signal travels in the form of-

(a) Lightwave
(c) Microwave
(d) Electric wave

[R.A.S./R.T.S.(Pre) 2012]

34. Consider the following statements :

1. Fibre optics is based on the principle of total internal refection.
2. In an optical fibre communication system, power consumption is extremely low.
3. Optical fibre communications are free from radio frequency interference.
4. In India, Reliance Group of Industries is engaged in the manufacture of the optical fbre.

Which of these statements are correct :

(a) 1, 2 and 3
(b) 1, 2 and 4
(c) 1, 3 and 4
(d) 2, 3 and 4

[U.P. P.C.S. (Pre) 2003, U.P. U.D.A./L.D.A. (Pre) 2002, U.P. P.C.S. (Pre) 2001]

35. ‘Endoscope’ used by the doctors for examining the inside of patient’s stomach, works on the principle of-

(a) Refection of light
(b) Dispersion of light
(c) Refraction of light
(d) Total internal refection of light

[U.P. Lower Sub. (Pre) 2009]

36. An endoscope is used by a physician to view the internal parts of a body organ. It is based on the principle of –

(a) Refraction of light
(b) Refection of light
(c) Total internal reflection of light
(d) Dispersion of light

[U.P.P.C.S. (Pre) 2010, U.P.P.C.S. (Mains) 2009, U.P.P.C.S. (Spl) (Mains) 2008, I.A.S. (Pre) 1999]

37. The reason of mirage is

(a) Interference of light
(b) Diffraction of light
(c) Polarization of light
(d) Total internal refection of light

[U.P.P.C.S.(Pre) 2012, U.P.P.C.S. (Pre) 1995]

38. Mirage formation is an example of –

(a) Refraction
(b) Dispersion
(c) Total internal refection
(d) Difraction

[U.P.P.C.S. (Mains) 2014, U.P. U.D.A./L.D.A. (Pre) 2013, U.P. Lower Sub. (Mains) 2013]

39. Consider the following natural phenomena :

1. Terrestrial heating
2. Refection of light
3. Refraction of light
4. Diffraction of light

Due to which of these phenomena is mirage formed ?

(a) 1 and 2
(b) 2, 3 and 4
(c) 1 and 3
(d) 4 only

[I.A.S. (Pre) 2002]

40. Which one of the following reflects back more sunlight as compared to other three?

(a) Sand Desert
(c) Land covered with fresh snow
(d) Prairie land

[U.P. P.C.S. (Pre) 2021]

41. The technique to integrate and mark the image of a three-dimensional object is

(a) Audiography
(b) Lexicography
(c) Photography
(d) Holography

[R.A.S./R.T.S. (Pre) 1999, R.A.S./R.T.S. (Pre) 1996]

42. Which of the following is used to take 3-dimensional pictures –

(a) Photography
(b) Holography
(d) None of the above

[U.P.P.C.S. (Mains) 2008, U.P.P.C.S. (Pre) 1990]

43. generating images on a screen by focusing an electronic beam on phosphorus-coated screen is called –

(a) Master Scan
(b) Total Scan
(c) Roster Scan

[R.A.S./R.T.S. (Pre) 1994-95]

44. ‘Raman effect’ deals with the light rays passing through

(a) Only fuids
(b) Only prisms
(c) Only diamonds
(d) All transparent medium

[R.A.S./R.T.S. (Pre) 1992]

45. For reproducing sound, a CD (Compact Disc) audio player uses a :

(a) Quartz crystal
(b) Titanium needle
(c) Laser beam
(d) Barium titanic ceramic

[I.A.S. (Pre) 2000]

46. When a CD (compact disc used in audio and video systems) is seen in sunlight, rainbow-like colours is seen. This can be explained on the basis of the phenomenon of :

(a) Reflection and diffraction
(b) Reflection and transmission
(c) Diffraction and transmission
(d) Refraction, diffraction, and transmission

[I.A.S. (Pre) 2000]

47. Consider the following statements :

1. Light of longer wavelength is scattered much more than the light of shorter wavelength.
2. The speed of visible light in water is 0.95 times the speed in vacuum.
3. Radio waves are produced by rapidly oscillating electrical currents.
4. To detect over-speeding vehicles, police use the Doppler effect of reflected short radio waves.

Which of these statements are correct?

(a) 1 and 2
(b) 1 and 3
(c) 2 and 4
(d) 3 and 4

[I.A.S. (Pre) 2002]

48. Assertion (A) : In a motion picture, usually 24 frames are projected every second over the whole length of the film.
Reason (R) : An image formed on the retina of eye persists for about 0.1s after the removal of the stimulus.
Code :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not a correct explanation of (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true

[I.A.S. (Pre) 2000]

49. Television signals cannot be received beyond a certain distance because :

(a) Signals are weak
(b) Antenna is weak
(c) Air absorbs signals
(d) The surface of the earth is curved

[U.P.P.S.C. (GIC) 2010, U.P.P.C.S. (Pre) 1994]

50. The technique used to transmit audio signals in television broadcasts is :

(a) Amplitude Modulation
(b) Frequency Modulation
(c) Pulse Code Modulation
(d) Time Division Multiplexing

[U.P.P.C.S. (Mains) 2007, I.A.S. (Pre) 1995]

51. In the human eye, light rays get transformed into neural impulses at :

(a) Cornea
(b) Pupil
(c) Retina
(d) Lens

[U.P.P.C.S. (Pre) 1997]

52. The image formed on Retina is :

(a) Equal to object but inverted
(b) Smaller than object but straight
(c) Smaller than object but inverted
(d) Equal to object but straight

[U.P.P.C.S. (Spl) (Mains) 2004, U.P.P.C.S. (Pre) 1995]

53. Which type of image of an object is formed by eye lens of the retina?

(a) Erect and Real
(b) Erect and Virtual
(c) Inverted and Real
(d) Inverted and Virtual
(e) None of the above

[Chhattisgarh P.C.S. (Pre) 2015]

54. The principal reason why it is better to have two eyes than one is that:

(a) By having two eyes we can distinguish colour easily
(b) By having two eyes we can easily see in the dark as well in dim light.
(c) It gives a man a type of vision known as mosaic vision.
(d) It enhances distance and depth perception in us.

[R.A.S./R.T.S. (Pre) 1994-95]

55. Direct viewing of sun during total solar eclipse causes irreversible damage to eyes. The retinal burn is caused by which one of the following components of the sun rays?

(a) Heat
(b) Rainbow light
(c) Ultraviolet light
(d) Infrared light

[U.P.P.C.S. (Mains) 2003]

56. The colour of the star is an indication of its :

(a) Distance from the earth
(b) Temperature
(c) Luminosity
(d) Distance from the sun

[U.P.P.C.S. (Mains) 2008, U.P.P.C.S. (Pre) 2005, U.P.P.C.S. (Mains) 2003]

57. Difusion of light in the atmosphere takes place due to :

(a) Carbon dioxide
(b) Dust particles
(c) Helium
(d) Water vapours

[I.A.S. (Pre) 2003, U.P.P.C.S. (Pre) 2021]

58. Diffusion of light in the atmosphere takes place due to

(a) Carbon dioxide
(b) Dust particles
(c) Helium
(d) None of the above

[Jharkhand P.C.S. (Pre) 2013]

59. The colour of light is determined by its

(a) Amplitude
(b) Wavelength
(c) Intensity
(d) Velocity

[U.P.P.C.S. (Mains) 2014, U.P.P.C.S.(Pre) 2012]

60. Choose the correct statement.

(a) Wavelength of red light is less than violet light
(b) Wavelength of red light is more than violet light
(c) Wavelength of violet light is more than green light
(d) Wavelength of violet light is more than yellow light
(e) None of the above / More than one of the above

[64th B.P.C.S. (Pre) 2018]

61. Which one of the colours has the longest wavelength?

(a) Green
(b) Yellow
(c) Blue
(d) Red

[M.P.P.C.S. (Pre) 1997]

62. The light with the shortest wavelength is

(a) Red
(b) Yellow
(c) Blue
(d) Violet

[Uttarakhand P.C.S. (Pre) 2005]

63. In the visible spectrum, the colour having the shortest wavelength is :

(a) Red
(b) Yellow
(c) Blue
(d) Violet

[U.P.R.O./A.R.O. (Mains) 2014]

64. Which one among the following has the highest energy?

(a) Blue light
(b) Green light
(c) Red light
(d) Yellow light

[I.A.S. (Pre) 2009]

65. Which one of the following colours of white light is least deviated by the glass prism?

(a) Green colour
(b) Red colour
(c) Violet colour
(d) Orange colour

[U.P. R.O./A.R.O. (Pre) (Re. Exam) 2016]

66. Assertion (A): In the visible spectrum of light, red light is more energetic than green light.
Reason (R): The wavelength of red light is more than that of green light.
Code :

(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true, but R is not a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true

[I.A.S. (Pre) 2008]

67. The sun is visible to us a few minutes before the actual sunrise because of :

(a) Scattering of light
(b) Diffraction of light
(c) Total internal reflection of light
(d) Refraction of light

[R.A.S./R.T.S.(Pre) 2007]

68. The sun and the moon appear elliptical near the horizon because of :

(a) Refraction
(b) Optical illusion
(c) Interference phenomenon
(d) Their actual shape

[U.P.P.C.S. (Spl.) (Pre) 2008]

69. Red light is used in traffic signals because

(a) It has the longest wavelength.
(b) It is beautiful.
(c) It is visible to people even with bad eyesight.
(d) None of the above reasons.

[U.P.P.C.S. (Mains) 2013]

70. Assertion (A): The danger signal is made up of red colour.
Reason (R): The red colour is scattered the least.

Select the correct answer using the codes given below:

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true but (R) is false.
(d) (A) is false but (R) is true

[U.P.P.C.S. (Pre) 2007]

71. Red light signal is used as a danger signal because –

(a) Red light is scattered least
(b) This is comfortable for the eyes
(c) It produces the least chemical reaction
(d) It is least absorbed in air

[U.P.P.C.S. (Mains) 2008, U.P.P.C.S. (Mains) 2011, U.P.P.C.S. (Mains) 2005, U.P.P.C.S. (Pre) 1995]

72. The Sky appears blue due to –

(a) Blue color is scattered most
(b) The red color is scattered most
(c) Blue light is minimum absorbed by atmosphere
(d) Red light is ultimately absorbed by atmosphere

[U.P.U.D.A./L.D.A. (Pre) 2013]

73. The sky is blue because –

(a) Blue colour in the sunlight is more than other colours
(b) Short waves are scattered more than long waves by atmosphere
(c) Blue colour is more absorbing to eyes
(d) Atmosphere absorbs long wavelength more than short wavelength

[Uttarakhand P.C.S. (Pre) 2005, U.P. Lower Sub. (Pre) 1998, 39th B.P.S.C. (Pre) 1994]

74. The blue colour of the sky is due to –

(a) Scattering of light
(b) Dispersion of light
(c) Interference of light
(d) Emission of more blue light as compared to other colours by the sun.

[U.P.P.C.S. (Pre) (Re. Exam) 2015]

75. The sky appears blue due to –

(a) Diffraction of light
(b) Refection of light
(c) Refraction of light
(d) Scattering of light

[U.P.P.C.S. (Mains) 2011]

76. Consider the following statements :

1. The Sky appears blue because of scattering.
2. The main cause of the seven colours of the rainbow is the scattering of light.
3. At the time of sunrise, the sun appears red, due to scattering of light.

Choose the correct statement/s from the given options:

(a) Only 1 is true
(b) 1 and 3 is true
(c) Only 2 is true
(d) 2 and 3 is true

[Uttarakhand U.D.A./L.D.A. (Pre) 2003]

77. The red colour of the Sun at sunset and sunrise is due to –

(a) Scattering of light
(b) Refraction of light
(c) Total internal reflection of light
(d) Dispersion of light

[U.P.P.C.S. (Mains) 2013, U.P. P.C.S. (Pre) 1992]

78. An astronaut sees the colour of the sky as –

(a) Blue
(b) White
(c) Black
(d) Red

[U.P.P.C.S. (Mains) 2005]

79. When we see the sky from a plane in high altitude, then it seems –

(a) Blue
(b) Black
(c) White
(d) Red

[U.P.P.S.C. (R.I.) 2014]

80. The sea seems blue due to –

(a) Excess deepness
(b) Refection of sky and scattering of light by the drops of water
(c) Blue colour of water
(d) Upper layer of water

[40th B.P.S.C. (Pre) 1995]

81. The (Green) Grass appears green to us because :

(a) It refects green colour light to our eyes
(b) It absorbs green colour light
(c) It refects all other colour lights except that of green colour
(d) None of the above

[U.P. P.C.S. (Mains) 2017]

82. Suppose a rocketship is proceeding from the earth at a speed of 2/10th the velocity of light. A light in the rocketship appears blue to the passengers on the ship.

What colour would it appear to an observer on the earth?

(a) Blue
(b) Orange
(c) Yellow
(d) Yellow-Orange

[I.A.S. (Pre) 1995]

83. What will be the nature of image formed by a convex mirror when the position of object is between infinity and pole P of the mirror?

(a) Virtual and erect
(b) Real and erect
(c) Real and inverted
(d) Virtual and inverted

[Chhattisgarh P.C.S. (Pre) 2020]

84. In driving a car which type of mirror would you like to use for observing trafc at your back ?

(a) Concave mirror
(b) Spherical mirror
(c) Convex mirror
(d) Plain mirror

[Uttarakhand P.C.S. (Pre) 2005, U.P. P.C.S. (Pre) 1991]

85. Which one of the following types of mirror is used to see the traffic behind the car?

(a) Convex mirror
(b) Concave mirror
(c) Plane mirror
(d) Spherical mirror

[U.P.P.C.S. (Pre) 2015]

86. Which mirror is used as a rearview mirror in vehicles?

(a) Plain
(b) Convex
(c) Concave
(d) Cylindrical

[U.P.P.C.S (Pre) 2011, U.P.P.C.S. (Mains) 2010]

87. For shaving, one uses –

(a) Concave mirror
(b) Plain mirror
(c) Convex mirror
(d) None of these

[43rd B.P.S.C. (Pre) 1999]

88. The mirror, which is used in searchlights, is –

(a) Concave mirror
(b) Convex mirror
(c) Simple mirror
(d) None of these

[U.P.P.C.S.(Mains) 2009]

89. A dentist mirror is a –

(a) Cylindrical mirror
(b) Concave mirror
(c) Convex mirror
(d) Plane mirror

[U.P.P.C.S. (Mains) 2009]

90. The mirror used by a dentist to examine the teeth of patients is

(a) Concave
(b) Convex
(c) Plane
(d) Cylindrical

[U.P.P.C.S.(Pre) 2013, U.P.P.C.S. (Pre) (Re. Exam) 2015]

91. In order to avoid sunlight, which of the following colour combination for an umbrella is most appropriate?

(a) Top black & bottom white
(b) Top white & bottom black
(c) Only black
(d) Only white

[U.P.P.C.S. (Pre) 1993]

92. The image formed by an astronomical telescope is

(a) Virtual and diminished
(b) Virtual and magnified
(c) Real and diminished
(d) Real and magnified

[U.P.P.C.S. (Mains) 2013]

93. The number of images of an object placed between two parallel mirrors is :

(a) Two
(b) One
(c) Six
(d) Infinite

[U.P.P.C.S.(Mains) 2013, U.P.P.C.S. (Pre) 1994]

94. How many images will be formed if a point light source is placed between two parallel plane mirrors?

(a) Two
(b) Four
(c) Eight
(d) Infinite

[U.P.P.C.S. (Pre) 2015]

95. When a mirror is rotated by an angle θ, the reflected ray will rotate by :

(a) 0
(b) θ/2
(c) θ
(d) 2θ

[I.A.S. (Pre) 1996]

96. Assertion (A):Small glass beads fixed on traffic signals glow brightly when light falls upon them.
Reason (R) : Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected from a rarer medium.
Code :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not a correct explanation of (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true

[I.A.S. (Pre) 2000]

97. Light is made of seven colours. What is the method of separating the colours?

(a) The colours can be separated by a prism
(b) The colours can be separated by a flter
(c) The colours can be separated by plants
(d) The colours cannot be separated

[47th B.P.S.C. (Pre) 2005]

98. The correct order of colours in a rainbow is :

(a) Blue, green, violet
(b) Violet, green, blue
(c) Blue, yellow, green
(d) Blue, green, yellow

[R.A.S./R.T.S.(Pre) 1999]

99. A rainbow is produced when sunlight falls on drops of rain. which of the following physical phenomena are responsible for this?

1. Dispersion
2. Refraction

3. Internal reflection

Select the correct answer using the code given below :

(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) All of these

[I.A.S. (Pre) 2013]

100. Dispersion of light is possible by :

(a) Prism
(b) Convex lens
(c) Concave lens
(d) Simple mirror
(e) None of the above/More than one of the above

[66th B.P.S.C. (Pre) (Re. Exam) 2020]

101. Which one of the following colours is seen in the middle of a Rainbow ?

(a) Blue
(b) Green
(c) Red
(d) Yellow

[U.P.P.C.S. (Mains) 2012]

102. The terminal color bands of the rainbow are :

(a) Blue and Orange
(b) Green and Red
(c) Yellow and Green
(d) Violet and Red

[U.P. Lower Sub. (Mains) 2015]

103. In which direction the rainbow is seen at 12 noon?

(a) In the West
(b) In the South
(c) In the East
(d) It cannot be seen

[43rd B.P.S.C. (Pre) 1999]

104. Assertion (A) : A stick is dipped in water in a slanting position. If observed sideways, the stick appears short and bent at the surface of the water.
Reason (R) : A light coming from the stick undergoes scattering from water molecules giving the stick a short and bent appearance.
Code :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not a correct explanation of (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true

[I.A.S. (Pre) 2001]

105. Consider the following statements :

1. If a person looks at a coin which is in a bucket of water, the coin will appear to be closer than it really is.
2. If a person under water looks at a coin above the water surface, the coin will appear to be at a higher level than it really is.

Which of the above statements is/are correct ?

(a) 1 and 2
(b) 1 alone
(c) 2 alone
(d) Neither 1 nor 2

[I.A.S. (Pre) 1999]

106. An air bubble in water will act like a :

(a) Convex mirror
(b) Convex lens
(c) Concave mirror
(d) Concave lens

[U.P. Lower Sub. (Pre) 2013, U.P. U.D.A./L.D.A. (Spl) (Pre) 2010, U.P.P.C.S. (Spl) (Pre) 2008, I.A.S. (Pre) 1995]

107. An air bubble inside water behaves as a:

(a) Bifocal lens
(b) Convergent lens
(c) Divergent lens
(d) Cylindrical lens

[U.P.P.C.S. (Pre) 2002]

108. Two glass lenses of same focal length, one being convex and the other concave, are kept in contact, the combination will act as :

(a) convergent lens
(b) divergent lens
(c) plane glass sheet
(d) mirror

[U.P.P.S.C. (GIC) 2017]

109. The minimum height of a plane mirror to see the full-size image of a person is equal to –

(a) The height of the person
(b) Half the height of the person
(c) One-fourth the height of the person
(d) Double the height of the person

[U.P.P.C.S. (Pre) 2014, U.P.P.C.S. (Pre) 2011, U.P.P.C.S. (Mains) 2011, U.P. U.D.A./L.D.A. (Spl) (Mains) 2010]

110. The minimum height of mirror required to see whole stand up image of a man of height 1.50 meter shall be

(a) 0.75 metre
(b) 1.00 metre
(c) 1.50 metre
(d) 3.00 metre

[U.P.P.S.C. (R.I.) 2014]

111. The radius of curvature of the plane mirror is :

(a) Zero
(b) One
(c) Infinity
(d) Between one and infinity

[U.P. Lower Sub. (Pre) 2015]

112. To remove the defect of long-sightedness one uses –

(a) Concave lens
(b) Convex mirror
(c) Convex lens
(d) Concave mirror

[43rd B.P.S.C. (Pre) 1999, Chhattishgarh P.C.S. (Pre) 2016]

113. Which one of the following statements is not true for a person sufering from hypermetropia?

(a) The person can see far objects distinctly.
(b) The focal length of the lens is large.
(c) The image of the close objects is focused behind the retina.
(d) A concave lens is used to correct this defect.

[U.P.P.C.S. (Pre) 2010]

(a) Concave
(b) Convex
(c) Plain
(d) None of these

[44th B.P.S.C. (Pre) 2000]

115. Which of the following lenses is used to minimize Myopia?

(a) Convex lens
(b) Concave lens
(c) Cylindrical lens
(d) None of these

[U.P.P.C.S. (Mains) 2011, M.P.P.C.S. (Pre) 2008]

116. A myopic eye can be corrected by using a

(a) Convex lens
(b) Concave lens
(c) Cylindrical lens
(d) Plane Convex lens

[U.P.P.C.S. (Mains) 2008, U.P. Lower Sub. (Pre) 2002]

117. For the myopic eye, the defect is cured by –

(a) Convex lens
(b) Concave lens
(c) Cylindrical lens
(d) None of the above

[U.P.P.C.S. (Mains) 2013]

118. When a person enters into a dark room from the strong light area, he is not able to see clearly for some time. Later he gradually begins to see things, This is because-

(a) Changes in the size of pupil
(b) Changes in the diameter and focal length of lens
(c) Bleaching and reformation of Rhodopsins
(d) Eyes become familiar with darkness in course of time

[R.A.S./R.T.S.(Pre) 2008]

119. The focus in the eye is done by

(a) Change in the convexity of the lens
(b) To and fro movement of the lens
(c) To and fro movement of the retina
[(d) Change in the refractive index of the eye fuid]

U.P.P.S.C. (R.I.) 2014

120. The change of focal length of an eye lens is caused by action of the

(a) Pupil
(b) Retina
(c) Ciliary muscles
(d) Iris
(e) None of the above

[Chhattisgarh P.C.S. (Pre) 2014]

121. Which one of the following statement is not correct ?

(a) Mirage is an optical illusion arising due to total internal refection of light
(b) Concave mirrors are used in searchlights
(c) In summer, white or light coloured clothes are preferred to dark coloured clothes generally
(d) A convex mirror with a small aperture is used by doctors to examine, ear, nose or throat of a patient.

[U.P.P.C.S. (Mains) 2010]

122. The least distance of distinct vision is (cm.)

(a) 25
(b) 5
(c) 75
(d) 100

[U.P.P.C.S. (Mains) 2008]

123. For normal eyes what is the minimum distance for clear vision?

(a) 10 cm.
(b) 15 cm.
(c) 20 cm.
(d) 25 cm.
(e) 30 cm.

[Chhattisgarh P.C.S. (Pre) 2013]

124. The minimum distance of clear vision for a normal healthy eye of a human being is supposed to be :

(a) 50 cm
(b) 10 cm
(c) 15 cm
(d) 25 cm

[M.P. P.C.S. (Pre) 2016]

125. The power of a lens is measured in

(a) dioptre
(b) aeon
(c) lumen
(d) candela

[M.P.P.C.S. (Pre) 2017]

126. The power of the lens is measured in the:

(a) Watt
(b) Ampere
(c) Volt
(d) Dioptre
(e) None of the above/More than one of the above

[66th B.P.S.C. (Pre) (Re. Exam) 2020]

127. If the lens power of glass is +2 dioptre, its focal length will be-

(a) 200 cm
(b) 100 cm
(c) 50 cm
(d) 2 cm

[41st B.P.S.C. (Pre) 1996]

128. The power of the sunglass is –

(a) 0 Dioptre
(b) 1 Dioptre
(c) 2 Dioptre
(d) 4 Dioptre

[U.P.P.C.S. (Pre) 1995]

129. Which one of the following combinations of aperture and shutter speed of a camera will allow the maximum exposure?

(a) f-22, 1/60
(b) f-16, 1/125
(c) f-8, 1/250
(d) f-5. 6, 1/1000

[I.A.S. (Pre) 1994]

130. The retina of the eye is comparable to which of the following parts of a traditional camera?

(a) Film
(b) Lens
(c) Shutter
(d) Cover

[U.P.P.C.S (Pre) 2011]

131. In the human eye, the image of an object forms at

(a) Cornea
(b) Iris
(c) Pupil
(d) Retina

[M.P.P.C.S. (Pre) 2017, 2014, Uttarakhand Lower Sub. (Pre) 2010]

132. The human eye forms the image of an object at its –

(a) Cornea
(b) Iris
(c) Pupil
(d) Retina
(e) None of the above

[Chhattisgarh P.C.S. (Pre) 2014]

133. In long-sightedness, images are formed at the following :

(a) On Retina
(b) In front of Retina
(c) Behind Retina
(d) On Blind Spot

[U.P. R.O./A.R.O. (Mains) 2017]

134. The colour of an opaque object is due to the colour it–

(a) Absorbs
(b) Refracts
(c) Reflects
(d) Scatters

[I.A.S. (Pre) 1994]

135. Colour in a colour television is produced by a combination of three basic colours, they are :

(a) Red, blue and orange
(b) Red, green and blue
(c) Red, yellow and green
(d) Red, green and brown

[R.A.S./R.T.S. (Pre) 1992]

136. Which primary colours produce different shades on the TV screen?

(a) Red, green and blue
(b) Red, yellow and green
(c) Orange, green and purple
(d) Red, yellow, green and black

[Uttarakhand Lower Sub. (Pre) 2010]

137. When beams of red, blue, and green lights fall on the same spot, the color of the light becomes :

(a) Violet
(b) Red
(c) Yellow
(d) White

[R.A.S./R.T.S. (Pre) 2003]

138. Which is not a primary color?

(a) Black
(b) Yellow
(c) Red
(d) Blue

[M.P.P.C.S. (Pre) 2015]

139. Three colors are the primary colors. These are –

(a) Blue, Yellow and Red
(b) Blue, Green and Red
(c) Yellow, Green and Red
(d) Blue, Yellow and Red

[M.P.P.C.S. (Pre) 2005]

140. Consider the following statements :

1. If magenta and yellow coloured circles intersect, the intersected area will have a red colour.
2. If cyan and magenta coloured circles intersect, the intersected area will have a blue colour.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

[I.A.S. (Pre) 2007]

141. The number of colors contained in the sunlight is –

(a) 3
(b) 5
(c) 6
(d) 7

[U.P.P.C.S. (Mains) 2015]

142. Find out the odd color from the following options-

(a) Green
(b) Brown
(c) Red
(d) Yellow

[R.A.S./R.T.S. (Pre) 1999]

143. Consider the following phenomena-

1. Size of the Sun at dusk
2. Colour of the Sun at dawn
3. Moon being visible at dawn
4. Twinkle of stars in the sky
5. Polestar being visible in the sky

Which of the above are optical illusions?

(a) 1, 2, and 3
(b) 3, 4 and 5
(c) 1, 2 and 4
(d) 2, 3 and 5

[I.A.S. (Pre) 2013]