JEE Questions for Physics Ray Optics Quiz 12 - MCQExams.com

A plane glass slab is kept over various coloured letters, the letter which appears least raised is
  • Blue
  • Violet
  • Green
  • Red
A ray of light is incident on the surface of separation of a medium at an angle 45° and is refracted in the medium at an angle 30°. What will be the velocity of light in the medium
  • 1.96 × 108 m/s
  • 2.12 × 108 m/s
  • 3.18 × 108 m/s
  • 3.33 × 108 m/s
Absolute refractive indices of glass and water are 3/2 and 4/3 . The ratio of velocity of light in glass and water will be
  • 4 : 3
  • 8 : 7
  • 8 : 9
  • 3 : 4
The ratio of thickness of plates of two transparent mediums A and B is 6 : 4. If light takes equal time in passing through them, then refractive index of B with respect to A will be
  • 1.4
  • 1.5
  • 1.75
  • 1.33
Spherical aberration in a lens
  • Is minimum when most of the deviation is at the first surface
  • Is minimum when most of the deviation is at the second surface
  • Is minimum when the total deviation is equally distributed over the two surface
  • Does not depend on the above consideration
Each quarter of a vessel of depth H is filled with liquids of the refractive indices n1, n2, n3 and n4 from the bottom respectively. The apparent depth of the vessel when looked normally is

  • Physics-Ray Optics-85948.png
  • 2)
    Physics-Ray Optics-85949.png

  • Physics-Ray Optics-85950.png

  • Physics-Ray Optics-85951.png
A ray of light passes through four transparent media with refractive indices μ1, μ2, μ3 and μ4 as shown in the figure. The surfaces of all media are parallel. If the emergent ray CD is parallel to the incident ray AB, we must have
Physics-Ray Optics-85953.png
  • μ1 = μ2
  • μ2 = μ3
  • μ3 = μ4
  • μ4 = μ1
An under water swimmer is at a depth of 12 m below the surface of water. A bird is at a height of 18 m from the surface of water, directly above his eyes. For the swimmer the bird appears to be at a distance from the surface of water equal to (Refractive Index of water is 4/3 )
  • 24 m
  • 12 m
  • 18 m
  • 9 m
The optical path of a monochromatic light is same if it goes through 4.0 cm of glass or 4.5 cm of water. If the refractive index of glass is 1.53, the refractive index of the water is
  • 1.30
  • 1.36
  • 1.42
  • 1.46
Which of the following statement is true
  • Velocity of light is constant in all media
  • Velocity of light in vacuum is maximum
  • Velocity of light is same in all reference frames
  • Laws of nature have identical form in all reference frames
A ray of light is incident on a transparent glass slab of refractive index 1.62. The reflected and the refracted rays are mutually perpendicular. The angle of incidence is
  • 58.3°
  • 50°
  • 35°
  • 30°
A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised up by 1 cm. To what depth should the water be poured into the beaker so that coin is 4 again in focus ? (Refractive index of water is 4/3)
  • 1 cm
  • 4/3 cm
  • 3 cm
  • 4 cm
Velocity of light in glass whose refractive index with respect to air is 1.5 is 2 × 108 m/s and in certain liquid the velocity of light found to be 2.5 × 108 m/s. The refractive index of the liquid with respect to air is
  • 0.64
  • 0.80
  • 1.20
  • 1.44
A thin oil layer floats on water. A ray of light making an angle of incidence of 40° shines on oil layer. The angle of refraction of light ray in water is
( μoil = 1.45, μwater = 1.33
  • 36.1°
  • 44.5°
  • 26.8°
  • 28.9°
Velocity of light in a medium is 1.5 × 108 m/s. Its refractive index will be
  • 8
  • 6
  • 4
  • 2
The wavelength of sodium light in air is 5890 Å. The velocity of light in air is 3 × 108 ms–1. The wavelength of light in a glass of refractive index 1.6 would be close to
  • 5890 Å
  • 3681 Å
  • 9424 Å
  • 15078 Å
The mean distance of sun from the earth is 1.5 × 108 km (nearly). The time taken by the light to reach earth from the sun is
  • 0.12 min
  • 8.33 min
  • 12.5 mm
  • 6.25 min
Refractive index of air is 1.0003. The correct thickness of air column which will have one more wavelength of yellow light (6000 Å) than in the same thickness in vacuum is
  • 2 mm
  • 2 cm
  • 2 m
  • 2 km
An astronaut in a spaceship see the outer space as
  • White
  • Black
  • Blue
  • Red
Speed of light is maximum in
  • Water
  • Air
  • Glass
  • Diamond
If the wavelength of light in vacuum be λ, the wavelength in a medium of refractive index n will be

  • Physics-Ray Optics-85966.png
  • 2)
    Physics-Ray Optics-85967.png

  • Physics-Ray Optics-85968.png

  • Physics-Ray Optics-85969.png

Physics-Ray Optics-85971.png
  • 30°
  • 45°
  • 60°
  • 75°
A ray of light strikes a transparent rectangular slab (of refractive index √2 ) at an angle of incidence of 45°. The angle between the reflected and refracted rays is
  • 75°
  • 90°
  • 105°
  • 120°
A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his water proof flash light
  • He must direct the beam vertically upwards
  • He has to direct the beam horizontally
  • He has to direct the beam at an angle to the vertical which is slightly less than the critical angle of incidence for total internal reflection
  • He has to direct the beam at an angle to the vertical which is slightly more than the critical angle of incidence for the total internal reflection
Finger prints on a piece of paper may be detected by sprinkling fluorescent powder on the paper and then looking it into
  • Mercury light
  • Sunlight
  • Infrared light
  • Ultraviolet light
The wavelength of light in two liquids \'x\' and \'y\' is3500 Åand 7000 Å, then the critical angle of x relative to y will be
  • 60°
  • 45°
  • 30°
  • 15°
A fish is a little away below the surface of a lake. If the critical angle is 49°, then the fish could see things above the water surface within an angular range of θ° where
Physics-Ray Optics-85975.png
  • θ = 49o
  • θ = 90o
  • θ = 98o

  • Physics-Ray Optics-85976.png
For total internal reflection to take place, the angle of incidence i and the refractive index μ of the medium must satisfy the inequality

  • Physics-Ray Optics-85978.png
  • 2)
    Physics-Ray Optics-85979.png

  • Physics-Ray Optics-85980.png

  • Physics-Ray Optics-85981.png
A transparent solid cylindrical rod has a refractive index of 2/√3.It is surrounded by air. A light ray is incident at the mid-point of one end of the rod as shown in the figure
The incident angle θ for which the light ray grazes along the wall of the rod is
Physics-Ray Optics-85983.png

  • Physics-Ray Optics-85984.png
  • 2)
    Physics-Ray Optics-85985.png

  • Physics-Ray Optics-85986.png

  • Physics-Ray Optics-85987.png
Total internal reflection of a ray of light is possible when the (ic= critical angle, i = angle of incidence)
  • Ray goes from denser medium to rarer medium and i c
  • Ray goes from denser medium to rarer medium and i >ic
  • Ray goes from rarer medium to denser medium and i >ic
  • Ray goes from rarer medium to denser medium and i c
Critical angle is that angle of incidence in the denser medium for which the angle of refraction in rarer medium is
  • 0°
  • 57°
  • 90°
  • 180°
The critical angle for diamond (refractive index =is
  • About 20°
  • 60°
  • 45°
  • 30°
The reason for shining of air bubble in water is
  • Diffraction of light
  • Dispersion of light
  • Scattering of light
  • Total internal reflection of light
With respect to air critical angle in a medium for light of red colour [λ1] is θ. Other facts remaining same, critical angle for light of yellow colour [λ2] will be
  • θ
  • More than θ
  • Less than θ

  • Physics-Ray Optics-85990.png
When a ray of light emerges from a block of glass, the critical angle is
  • Equal to the angle of reflection
  • The angle between the refracted ray and the normal
  • The angle of incidence for which the refracted ray travels along the glass-air boundary
  • The angle of incidence

Physics-Ray Optics-85992.png

  • Physics-Ray Optics-85993.png
  • 2)
    Physics-Ray Optics-85994.png

  • Physics-Ray Optics-85995.png

  • Physics-Ray Optics-85996.png
A point source of light is kept at a depth of h in water of refractive index 4/3. The radius of the circle at the surface of water through which light emits is

  • Physics-Ray Optics-85998.png
  • 2)
    Physics-Ray Optics-85999.png

  • Physics-Ray Optics-86000.png

  • Physics-Ray Optics-86001.png
A ray of light enters from a rarer to a denser medium. The angle of incidence is i. Then the reflected and refracted rays are mutually perpendicular to each other. The critical angle for the pair of media is
  • sin–1 (cot i)
  • cos–1 (tan i)
  • sin–1 (tan i)
  • tan–1 (sin i)
The refractive index of water is 1.33. The direction in which a man under water should look to see the settingsun is
  • 49° to the horizontal
  • 90° with the vertical
  • 49° to the vertical
  • Along the horizontal
A light ray from air is incident (as shown in figure) at one end of a glass fiber (refractive index µ = 1.5 ) making an incidence angle of 60° on the lateral surface, so that it undergoes a total internal reflection. How much time would it take to traverse the straight fiber oflength 1 km
Physics-Ray Optics-86004.png
  • 3.33 μs
  • 6.67 μs
  • 5.77 μs
  • 3.85 μs
A ray of light traveling in water is incident on its surface open to air. The angle of incidence is θ, which is less than the critical angle. Then there will be
  • Only a reflected ray and no refracted ray
  • Only a refracted ray and no reflected ray
  • A reflected ray and a refracted ray and the angle between them would be less than 180°–2θ
  • A reflected ray and a refracted ray and the angle between them would be greater than 180°– 2θ
Consider telecommunication through optical fibres. Which of the following statements is not true
  • Optical fibres may have homogeneous core with a suitable cladding
  • Optical fibres can be of graded refractive index
  • Optical fibres are subject to electromagnetic interference from outside
  • Optical fibres have extremely low transmission loss.
White light is incident on the interface of glass and air as shown in the figure. If green light is just totally internally reflected then the emerging ray in aircontains
Physics-Ray Optics-86007.png
  • Yellow, orange, red
  • Violet, indigo, blue
  • All colours
  • All colours except green
Material A has critical angle iA, and material B hascritical angle iB (iB> iA) then which of the following istrue
(i) Light can be totally internally reflected when it passes from B to A
(ii) Light can be totally internally reflected when it passes from A to B
(iii) Critical angle for total internal reflection is iB – iA

Physics-Ray Optics-86009.png
  • (i) and (iii)
  • (i) and (iv)
  • (ii) and (iii)
  • (ii) and (iv)
In the figure shown, for an angle of incidence 45°, at the top surface, what is the minimum refractive index needed for total internal reflection at vertical face
Physics-Ray Optics-86011.png

  • Physics-Ray Optics-86012.png
  • 2)
    Physics-Ray Optics-86013.png

  • Physics-Ray Optics-86014.png

  • Physics-Ray Optics-86015.png
Critical angle for light going from medium (i) to (ii) is θ. The speed of light in medium (i) is v then speed inmedium (ii) is
  • v (1– cos θ)
  • v / sin θ
  • v / cos θ
  • v (1– sin θ)
If light travels a distance x in t1 sec in air and 10x distance in t2 sec in a medium, the critical angle of the medium will be

  • Physics-Ray Optics-86018.png
  • 2)
    Physics-Ray Optics-86019.png

  • Physics-Ray Optics-86020.png

  • Physics-Ray Optics-86021.png
Figure shows a mixture of blue, green and red coloured rays incident normally on a right angled prism. The critical angles of the material of the prism for red, green and blue are 46°, 44° and 43° respectively. Thearrangement will separate
Physics-Ray Optics-86023.png
  • Green colour from red and blue
  • All the three colours
  • Red colour from blue and green
  • Blue colour from red and green
A point source of light is kept below the surfaces ofwater in a pond
  • Light emerges from every point of the surface of the pond
  • No light is transmitted from the surface of the pond
  • All the light emitted by the source emerges from a circular region of the pond.
  • Some of the light emitted by the source emerges from a circular region of pond.
Transmission of light to large distances through optical fibers is bases on
  • Dispersion
  • Refraction
  • Total internal reflection
  • Interference
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