JEE Questions for Physics Ray Optics Quiz 29 - MCQExams.com

Assertion In optical fibre, the diameter of the core is kept small.
Reason This smaller diameter of the core ensures that the fibre should have incident angle more than the critical angle required for total internal reflection.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The mirrors used in search lights are parabolic and not concave spherical.
Reason In a concave spherical mirror the image formed is always virtual.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The cloud in sky generally appear to be whitish.
Reason Diffraction due to cloud is efficient in equal measure at all wavelengths.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Just before setting, the sun may appear to be elliptical. This happens due to refraction.
Reason Refraction of light ray through the atmosphere may cause different magnification in mutually perpendicular directions.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Critical angle of light passing from glass to air is minimum for violet colour.
Reason The wavelength of violet light is greater than the light of other colours
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion We cannot produce a real image by plane or convex mirrors under any circumstances.
Reason The focal length of a convex mirror is always taken as positive.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Diamond glitters brilliantly.
Reason Diamond does not absorb sunlight.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Within a glass slab, a double convex air bubble is formed. This air bubble behaves like a converging lens.
Reason Refractive index of air is more than the refractive index of glass.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
AAssertion The images formed by total internal reflections are much brighter than those formed by mirrors or lenses.
Reason There is no loss of intensity in total internal reflection.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The focal length of lens does not change when red light is replaced by blue light.
Reason The focal length of lens does not depends on colour of light used.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion There is no dispersion of light refracted through a rectangular glass slab.
Reason Dispersion of light is the phenomenon of splitting of a beam of white light into its constituent colours.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion All the materials always have the same colour, whether viewed by reflected light or through transmitted light.
Reason The colour of material does not depend on nature of light.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion By roughening the surface of a glass sheet its transparency can be reduced.
Reason Glass sheet with rough surface absorbs more light.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion By increasing the diameter of the objective of telescope, we can increase its range.
Reason The range of a telescope tells us how far away a star of some standard brightness can be spotted by telescope.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion For the sensitivity of a camera, its aperture should be reduced.
Reason Smaller the aperture, image focusing is also sharp.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If objective and eye lenses of a microscope are interchanged then it can work as telescope.
Reason The objective of telescope has small focal length.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The resolving power of a telescope is more if the diameter of the objective lens is more.
Reason Objective lens of large diameter collects more light.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
A ray of light makes an angle of 10° with the horizontal above it and strikes a plane mirror which is inclined at an angle θ to the horizontal. The angle θ for which the reflected ray becomes vertical is
  • 40°
  • 50°
  • 80°
  • 100°
Assertion The resolving power of an electron microscope is higher than that of an optical microscope.
Reason The wavelength of electron is more than the wavelength of visible light.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If the angles of the base of the prism are equal, then in the position of minimum deviation, the refracted ray will pass parallel to the base of prism.
Reason In the case of minimum deviation, the angle of incidence is equal to the angle of emergence.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Dispersion of light occurs because velocity of light in a material depends upon its colour.
Reason The dispersive power depends only upon the material of the prism, not upon the refracting angle of the prism.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An empty test tube dipped into water in a beaker appears silver, when viewed from a suitable direction.
Reason Due to refraction of light, the substance in water appears silvery.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The refractive index of a prism depends only on the kind of glass of which it is made of and the colour of light
Reason The refractive index of a prism depends upon the refracting angle of the prism and the angle of minimum deviation
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion It is impossible to photograph a virtual image.
Reason The rays which appear diverging from a virtual image fall on the camera and a real image is captured.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The speed of light in a rarer medium is greater than that in a denser medium
Reason One light year equals to 9.5 × 1012 km
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
In an astronomical telescope in normal adjustment, a straight black line of length L is drawn on the objective lens. The eyepiece forms a real image of this line. The length of this image is I. The magnification of the telescope is

  • Physics-Ray Optics-87302.png
  • 2)
    Physics-Ray Optics-87303.png

  • Physics-Ray Optics-87304.png

  • Physics-Ray Optics-87305.png
Three lenses L1, L2, L3are placed co-axially as shown infigure. Focal length\'s of lenses are given 30 cm, 10 cm and 5 cm respectively. If a parallel beam of light falling on lens L1, emerging L3as a convergent beam such that it converges at the focus of L3. Distance between L1 and L2 will be
Physics-Ray Optics-87307.png
  • 40 cm
  • 30 cm
  • 20 cm
  • 10 cm
An object is placed at a point distant x from the focus of a convex lens and its image is formed at Ias shown in the figure. The distances x, x\' satisfy the relation
Physics-Ray Optics-87309.png

  • Physics-Ray Optics-87310.png
  • 2)
    Physics-Ray Optics-87311.png

  • Physics-Ray Optics-87312.png

  • Physics-Ray Optics-87313.png
In a thin spherical fish bowl of radius 10 cm filled with water of refractive index 4/3 there is a small fish at a distance of 4 cm from the centre C as shown in figure. Where will the image of fish appear, if seen from E
Physics-Ray Optics-87316.png
  • 5.2 cm
  • 7.2 cm
  • 4.2 cm
  • 3.2 cm

Physics-Ray Optics-87318.png
  • A distance of 0.2 m from the water surface
  • A distance of 0.6 m from the water surface
  • A distance of 0.3 m from the water surface
  • The same location of fish
Which of the following ray diagram show physically possible refraction
Physics-Ray Optics-87325.png
  • (i)
  • (ii)
  • (iii)
  • None of these
Following figure shows the multiple reflections of a light ray along a glass corridor where the walls are either parallel or perpendicular to one another. If the angle of incidence at point P is 30°, what are the angles of reflection of the light ray at points Q R, S and T respectively
Physics-Ray Optics-87327.png
  • 30°, 30°, 30°, 30°
  • 30°, 60°, 30°, 60°
  • 30°, 60°, 60°, 30°
  • 60°, 60°, 60°, 60°
When the rectangular metal tank is filled to the top with an unknown liquid, as observer with eyes level with the top of the tank can just see the corner E; a ray that refracts towards the observer at the top surface of the liquid is shown. The refractive index of the liquid will be
Physics-Ray Optics-87329.png
  • 1.2
  • 1.4
  • 1.6
  • 1.9
A concave mirror and a converging lens (glass with µ = 1.both have a focal length of 3 cm when in air.When they are in water (µ = 4/their new focal lengths are
  • fLens = 12 cm, fMirror = 3 cm
  • fLens = 3 cm, fMirror = 12 cm
  • fLens = 3 cm, fMirror = 3 cm
  • fLens = 12 cm, fMirror = 12 cm
A ray of light strikes a plane mirror Mat an angle of 45° as shown in the figure. After reflection, the ray passes through a prism of refractive index 1.5 whose apex angle is 4°. The total angle through which the ray is deviated is
Physics-Ray Optics-87331.png
  • 90°
  • 91°
  • 92°
  • 93°
A point source of light S is placed at the bottom of a vessel containing a liquid of refractive index 5/3. A person is viewing the source from above the surface. There is an opaque disc D of radius 1 cm floating on the surface of the liquid. The centre of the disc lies vertically above the source S. The liquid from the vessel is gradually drained out through a tap. The maximum height of the liquid for which the source cannot be seen at all from above is
Physics-Ray Optics-87334.png
  • 1.50 cm
  • 1.64 cm
  • 1.33 cm
  • 1.86 cm
A point object is placed mid-way between two plane mirrors distance \'a\' apart. The plane mirror forms aninfinite number of images due to multiple reflection. The distance between the nth order image formed in the two mirrors is
  • na
  • 2 na
  • na/2
  • n2 a
PQR is a right angled prism with other angles as 60° and 30°. Refractive index of prism is 1.5. PQ has a thin layer of liquid. Light falls normally on the face PR. For total internal reflection, maximum refractive index of liquid is
Physics-Ray Optics-87338.png
  • 1.4
  • 1.3
  • 1.2
  • 1.6
In a given direction, the intensities of the scattered light by a scattering substance for two beams of light are in the ratio of 256: 81. The ratio of the frequency of the first beam to the frequency of the second beam is
  • 64 : 127
  • 4 : 3
  • 64 : 27
  • 2 : 1
A telescope using light having wavelength 5000 Å and using lenses of focal 2.5 and 30 cm. If the diameter of the aperture of the objective is 10 cm, then the resolving limit and magnifying power of the telescope is respectively
  • 6.1 × 10–6 rad and 12
  • 5.0 × 10–6 rad and 12
  • 6.1 × 10–6 rad and 8.3 × 10–2
  • 5.0 × 10–6 rad and 8.3 × 10–2
A lens when placed on a plane mirror then object needle and its image coincide at 15 cm. The focal length of the lens is
  • 15 cm
  • 30 cm
  • 20 cm
  • ∞
When sunlight is scattered by minute particles of atmosphere, the intensity of light scattered away is proportional to
  • (wavelength of light)4
  • (frequency of light)4
  • (wavelength of light)–2
  • (frequency of light)2
A glass slab consists of thin uniform layers of progressively decreasing refractive indices RI (see figure) such that the RI of any layer is μ — m∆μ. Here, μ and ∆µ denote the RI of zeroth layer and the difference in RI between any two consecutive layers, respectively. The integer m = 0, 1, 2, 3,... denotes the numbers of the successive layers.
A ray of light from the zeroth layer enters the first layer at an angle of incidence of 30°. After undergoing the mth refraction, the ray emerges parallel to the interface. If μ = 1.5 and ∆μ = 0.015, the value of m is
Physics-Ray Optics-87347.png
  • 20
  • 30
  • 40
  • 50

Physics-Ray Optics-87349.png

  • Physics-Ray Optics-87350.png
  • 2)
    Physics-Ray Optics-87351.png

  • Physics-Ray Optics-87352.png

  • Physics-Ray Optics-87353.png
A right angled prism of refractive index μ1 is placed in a rectangular block of refractive index μ2, which is surrounded by a medium of refractive index μ3 , as shown in the figure, A ray of light e enters the rectangular block at normal incidence. Depending upon the relationships between μ1 , μ2 and μ3 , it takes one of the four possible paths ef, eg, eh or ei.
Physics-Ray Optics-87355.png
  • P = 2, Q = 3, R = 1, S = 4
  • P = 1, Q = 2, R = 4, S = 3
  • P = 4, Q = 1, R = 2, S = 3
  • P = 2, Q = 3, R = 4, S = 1
Two thin lenses, one of focal length + 60 cm and the other of focal length -20 cm are put in contact. The combined focal length is
  • + 15 cm
  • – 15 cm
  • + 30 cm
  • – 30 cm
P1, P2 are powers of two lenses and ω1, ω2 are dispersive powers of their materials. The condition for the combination to be achromatic is
  • P1 = P2
  • ω1 = ω2

  • Physics-Ray Optics-87357.png

  • Physics-Ray Optics-87358.png
A man’s near point is 0.5 m and for point is 3 m. Power of spectacle lenses required for (i) reading purposes, (ii) seeing distant objects, respectively, are
  • -2 D and +3 D
  • +2 D and -3 D
  • +2 D and -0.33 D
  • -2 D and +0.33 D
Resolving power of reflecting type telescope increases with
  • decrease in wavelength of incident light
  • increase in wavelength of incident light
  • increase in diameter of objective mirror
  • None of these
  • Both 1 and 3
A Sound wave travels from air to water. the angle of incidence is 1 α and the angle of reflection is 2 α If the Snell\'s Law is valid then,___________________.
  • α1 ≥ α2
  • α1 = α2
  • α1 > α2
  • α1 < α2
0:0:1


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