JEE Questions for Physics Ray Optics Quiz 24 - MCQExams.com

The wavelength of light in air and some other medium are respectively λa and λm.The refractive index ofmedium is
  • λa /λm
  • λm /λa
  • λa × λm
  • None of these
A transparent cube of 15 cm edge contains a small air bubble. Its apparent depth when viewed through one face is 6 cm and when viewed through the opposite face is 4 cm. Then the refractive index of the material of the cube is
  • 2.0
  • 2.5
  • 1.6
  • 1.5
In vacuum the speed of light depends upon
  • Frequency
  • Wave length
  • Velocity of the source of light
  • None of the above
A cut diamond sparkles because of its
  • Hardness
  • High refractive index
  • Emission of light by the diamond
  • Absorption of light by the diamond
Critical angle of light passing from glass to air isminimum for
  • Red
  • Green
  • Yellow
  • Violet
If the critical angle for total internal reflection from a medium to vacuum is 30°, the velocity of light in the medium is
  • 3 × 108 m/s
  • 1.5 × 108 m/s
  • 6 × 108 m/s

  • Physics-Ray Optics-86808.png
A ray of light is incident at an angle i from denser to rare medium. The reflected and the refracted rays are mutually perpendicular. The angle of reflection and the angle of refraction are respectively r and r\', then the critical angle will be
Physics-Ray Optics-86810.png

  • Physics-Ray Optics-86811.png
  • 2)
    Physics-Ray Optics-86812.png

  • Physics-Ray Optics-86813.png

  • Physics-Ray Optics-86814.png
A diver at a depth of 12 m in water (µ = 4/sees the sky in a cone of semi-vertical angle
  • sin–1 (4/3)
  • tan–1 (4/3)
  • sin–1 (3/4)
  • 90°
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
  • θλ1 / λ2
\'Mirage\' is a phenomenon due to
  • Reflection of light
  • Refraction of light
  • Total internal reflection of light
  • Diffraction of light
The speed of light in media M1 and M2 is 1.5 × 108 m/s and 2.0 × 108 m/s respectively. A ray of light entersfrom medium M1 to M2 at an incidence angle i. If the ray suffers total internal reflection, the value of i is
  • Equal to sin–1(2/3)
  • Equal to or less than sin–1(3/5)
  • Equal to or greater than sin–1(3/4)
  • Less than sin–1(2/3)
The phenomenon utilized in an optical fibre is
  • Refraction
  • Interference
  • Polarization
  • Total internal reflection
The velocity of light in a medium is half its velocity in air. If ray of light emerges from such a medium into air, the angle of incidence, at which it will be totally internally reflected, is
  • 15°
  • 30°
  • 45°
  • 60°
A ray of light propagates from glass (refractive index= 3/to water (refractive index = 4/3). The value of the critical angle

  • Physics-Ray Optics-86820.png
  • 2)
    Physics-Ray Optics-86821.png

  • Physics-Ray Optics-86822.png

  • Physics-Ray Optics-86823.png
Relation between critical angles of water and glass is
  • Cw>Cg
  • Cwg
  • Cw=Cg
  • Cw>Cg = 0
Optical fibres are related with
  • Communication
  • Light
  • Computer
  • None of these
Brilliance of diamond is due to
  • Shape
  • Cutting
  • Reflection
  • Total internal reflection
The critical angle for a medium is 60°. The refractive index of the medium is

  • Physics-Ray Optics-86826.png
  • 2)
    Physics-Ray Optics-86827.png

  • Physics-Ray Optics-86828.png

  • Physics-Ray Optics-86829.png
Glass has refractive index µ with respect to air and the critical angle for a ray of light going from glass to air is θ. If a ray of light is incident from air on the glass with angle of incidence θ, the corresponding angle of refraction is

  • Physics-Ray Optics-86831.png
  • 90°

  • Physics-Ray Optics-86832.png

  • Physics-Ray Optics-86833.png
An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of
  • Refraction
  • Reflection
  • Total internal reflection
  • Dispersion
A normally incident ray reflected at an angle of 90°. The value of critical angle is
  • 45°
  • 90°
  • 65°
  • 43.2°
The phenomena of total internal reflection is seen when angle of incidence is
  • 90°
  • Greater than critical angle
  • Equal to critical angle
  • 0°
A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3and the fish is 12 cm below the surface, the radius of this circle in cm is

  • Physics-Ray Optics-86836.png
  • 2)
    Physics-Ray Optics-86837.png

  • Physics-Ray Optics-86838.png

  • Physics-Ray Optics-86839.png
A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc which should be placed over the source on the surface of water to cut-off all light coming out of water is
  • 2 m
  • 6 m
  • 4 m
  • 3 m
Which of the following is not due to total internal reflection?
  • Brilliance of diamond
  • Working of optical fibre
  • Difference between apparent and real depth of a pond
  • Mirage on hot summer days
Light travels in two media A and B with speeds 1.8 × 108ms–1 and 2.4 × 108ms–1 respectively. Then, the critical angle between them is

  • Physics-Ray Optics-86842.png
  • 2)
    Physics-Ray Optics-86843.png

  • Physics-Ray Optics-86844.png

  • Physics-Ray Optics-86845.png
The radius of curvature for a convex lens is 40 cm, for each surface. Its refractive index is 1.5. The focal length will be
  • 40 cm
  • 20 cm
  • 80 cm
  • 30 cm
Minimum deviation is observed with a prism having angle of prism A, angle of deviation δ, angle of incidence iand angle of emergence e. We then have generally
  • i > e
  • i < e
  • i = e
  • i = e = δ
A thin lens has focal length f1 and its aperture has diameter d/2. It forms an image of intensity I. Now the central part of the aperture upto diameter d/2 is blockedby an opaque paper. The focal length and image intensity will change to

  • Physics-Ray Optics-86853.png
  • 2)
    Physics-Ray Optics-86854.png

  • Physics-Ray Optics-86855.png

  • Physics-Ray Optics-86856.png
Four lenses are made from the same type of glass. The radius of curvature of each face is given below. Which will have the greatest positive power?
  • 10 cm convex and 15 cm concave
  • 5 cm convex and 10 cm concave
  • 15 cm convex and plane
  • 20 cm convex and 30 cm concave
A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of combination is
  • –1.5 D
  • –6.5 D
  • + 6.5 D
  • + 6.67 D
Two similar plano-convex lenses are combined together in three different ways as shown in the adjoining figure. The ratio of the focal lengths in three cases will be
Physics-Ray Optics-86860.png
  • 2 : 2 : 1
  • 1 : 1 : 1
  • 1 : 2 : 2
  • 2 : 1 : 1
Two lenses of power +12 and –2 dioptres are placed in contact. What will the focal length of combination?
  • 10 cm
  • 12.5 cm
  • 16.6 cm
  • 8.33 cm
A concave and convex lens have the same focal length of 20 cm and are put into contact to form a lens combination. The combination is used to view an object of 5 cm length kept at 20 cm from the lens combination. As compared to the object, the image will be
  • Magnified and inverted
  • Reduced and erect
  • Of the same size as the object and erect
  • Of the same size as the object but inverted
If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be
  • 1.5
  • 1.66
  • 1.33
  • 3
The slit of a collimator is illuminated by a source as shown in the adjoining figures. The distance between the slit S and the collimating lens L is equal to the focal length of the lens. The correct direction of the emergent beam will be as shown in figure
Physics-Ray Optics-86865.png
  • 1
  • 3
  • 2
  • None of the figures
A converging lens is used to form an image on a screen. When upper half of the lens is covered by an opaque screen
  • Half the image will disappear
  • Complete image will be formed of same intensity
  • Half image will be formed of same intensity
  • Complete image will be formed of decreased intensity
A glass convex lens (µg = 1.has a focal length of 8 cm when placed in air. What would be the focal length of the lens when it is immersed in water (µw = 1.33)?
  • 2 m
  • 4 cm
  • 16 cm
  • 32 cm
If I1 and I2 be the size of the images respectively for the two positions of lens in the displacement method, then the size of the object is given by

  • Physics-Ray Optics-86867.png
  • 2)
    Physics-Ray Optics-86868.png

  • Physics-Ray Optics-86869.png

  • Physics-Ray Optics-86870.png
The radius of curvature of convex surface of a thin plano convex lens is 15 cm and refractive index of its material is 1.6. The power of the lens will be
  • + 1 D
  • –2 D
  • + 3 D
  • +4 D
A boy is trying to start a fire by focusing Sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the Sun is 1.39 × 109 m and its means distance from the earth is 1.5 × 1011 m. What is the diameter of the Sun\'s image on the paper?
  • 6.5 × 10–5 m
  • 12.4 × 10–4 m
  • 9.26 × 10–4 m
  • 6.5 × 10–4 m
A combination of two thin lenses with focal lengths f1 and f2 respectively forms an image of distant object at distance 60 cm when lenses are in contact. The position of this image shifts by 30 cm towards the combination when two lenses are separated by 10 cm. The corresponding values of f1 and f2 are
  • 30 cm, –60 cm
  • 20 cm, –30 cm
  • 15 cm, –20 cm
  • 12 cm, –15 cm
An achromatic combination of lenses is formed by joining
  • 2 convex lenses
  • 2 concave lenses
  • 1 convex lens and 1 concave lens
  • Convex lens and plane mirror
A plano convex lens (f = 20 cm) is silvered at plane surface. Now f will be
  • 20 cm
  • 40 cm
  • 30 cm
  • 10 cm
The focal length of convex lens is 30 cm and the size of image is quarter of the object, then the object distance is
  • 150 cm
  • 60 cm
  • 30 cm
  • 40 cm
A lens (focal length 50 cm) forms the image of a distant object which subtends an angle of 1 milli radian at the lens. What is the size of the image?
  • 5 mm
  • 1 mm
  • 0.5 mm
  • 0.1 mm
Two thin lenses of focal lengths f1 and f2 are in contact and coaxial. The combination is equivalent to a singlelens of power

  • Physics-Ray Optics-86881.png
  • 2)
    Physics-Ray Optics-86882.png

  • Physics-Ray Optics-86883.png

  • Physics-Ray Optics-86884.png
An equiconvex lens of glass of focal length 0.1 metre is cut along a plane perpendicular to principle axis into two equal parts. The ratio of focal length of new lenses formed is
  • 1 : 1
  • 1 : 2
  • 2 : 1

  • Physics-Ray Optics-86886.png
A achromatic combination is made with a lens of focal length f and dispersive power ω with a lens having dispersive power of 2ω. The focal length of second will be
  • 2 f
  • f/ 2
  • –f/2
  • –2f
When a glass lens with n = 1.47 is immersed in a trough of liquid, it looks to be disappeared. The liquid in the trough could be
  • Water
  • Kerosene
  • Glycerin
  • Alcohol
0:0:1


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