JEE Questions for Physics Ray Optics Quiz 6 - MCQExams.com

The resolution limit of the eye is 1 minute. At a distance x km from the eye, two persons stand with a lateral separation of 3 km. For the two persons to be just resolved by the naked eye, x should be
  • 10 km
  • 15 km
  • 20 km
  • 30 km
Ray optics is valid, when characteristic dimensions are
  • of the same order as the wavelength of light
  • much smaller than the wavelength of light
  • of the order of one millimetre
  • much larger than the wavelength of light
The image of a star (effectively a point source) is made by convergent lens of focal length 50 cm and diameter of aperture 5.0 cm. If the lens is ideal, and the effective wavelength in image formation is taken as 5 × 10–5 cm, the diameter of the image formed will be nearest to
  • Zero
  • 10–6 cm
  • 10–5 cm
  • 10–3 cm
Light travels through a glass plate of thickness t and having a refractive index µ. If c is the velocity of light in vacuum, the time taken by light to travel this thickness of glass is
  • t µ c
  • tc/µ
  • t/µc
  • µ t/c
Two thin lenses of focal length f 1 and f2 are placed coaxially in contact. The combination acts as a single lens of focal length

  • Physics-Ray Optics-85533.png
  • 2)
    Physics-Ray Optics-85534.png

  • Physics-Ray Optics-85535.png

  • Physics-Ray Optics-85536.png
A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an inverted image of the object coincident with it?
  • 12 cm
  • 30 cm
  • 50 cm
  • 60 cm
A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be
  • 10 cm
  • 15 cm
  • 20 cm
  • 30 cm
If the refractive index of a material of equilateral prism is √3 , then angle of minimum deviation of the prism is
  • 30º
  • 45º
  • 60º
  • 75º
An object of height 1.5 cm is placed on the axis of a convex lens of focal length 25 cm. A real image is formed at a distance of 75 cm from the lens. The size of image will be
  • 4.5 cm
  • 3.0 cm
  • 0.75 cm
  • 5 cm
An equiconvex lens of glass of focal length 0.1 m is cut along a plane perpendicular to principal axis into two equal parts. The ratio of focal length of new lenses formed is
  • 1 : 1
  • 1 : 2
  • 2 : 1
  • 2 : 1/2
A point source of light B, placed at a distance L in front of the centre of a mirror of width d, hangs vertically on a wall. A man walks in front of the mirror along a line parallels to the mirror at a distance 2 L from it as shown in Fig. The greatest distance over which he can see the image of the light source in the mirror is
Physics-Ray Optics-85543.png
  • d/2
  • d
  • 2d
  • 3d
Magnifying power of telescope can be increased by
  • increasing the length of telescope
  • increasing focal length of objective
  • increasing the diameter of objective
  • increasing the focal length of eye piece

Physics-Ray Optics-86556.png

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  • 2)
    Physics-Ray Optics-86558.png

  • Physics-Ray Optics-86559.png

  • Physics-Ray Optics-86560.png
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination?
  • – 6.5 D
  • – 1.5 D
  • 6.5 D
  • 1.5 D
A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is
  • ∞
  • 3 m
  • 6 m
  • 4 m
Wave lengths of light used in an optical instrument are λ = 4000 Ǻ and λ = 5000 Ǻ. The ratio of their respective resolving power is
  • 16 : 25
  • 5 : 4
  • 4 : 5
  • 9 : 1
The objective of an astronomical telescope has a large aperture to
  • reduce spherical aberration
  • increase span of observations
  • have high resolution
  • have low dispersion
The Cauchy’s dispersion formula is

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  • 2)
    Physics-Ray Optics-85551.png

  • Physics-Ray Optics-85552.png

  • Physics-Ray Optics-85553.png
An observer can see through a pin hole, the top end of a thin rod of height h placed as shown in Fig. The beaker height is 3h and its radius is h. When the beaker is filled with a liquid upto a height 2h, he can see the lower end of the rod. Then the refractive index of the liquid is
Physics-Ray Optics-85555.png
  • 5/2
  • 2)
    Physics-Ray Optics-85556.png
  • 3/2

  • Physics-Ray Optics-85557.png
The image formed by an objective of a compound microscope is
  • virtual and diminished
  • real and diminished
  • real and enlarged
  • virtual and enlarged
A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will
  • become zero
  • become infinite
  • reduce
  • increase
An equiconvex lens is cut into two halves along (i) XOX’ and (ii) YOY’ as shown in Fig. Let f, f’ and f’’ be the focal lengths of complete lens, of each half in case
(i) and of each half in case
(ii) respectively. Choose the correct statement from the following:
Physics-Ray Optics-85560.png
  • f’ = f, f’’ = 2f
  • f’ = 2f, f’’ = f
  • f’ = f, f’’ = f
  • f’ = 2f, f’’ = 2f
The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image.
  • 1.25 cm
  • 2.5 cm
  • 1.05 cm
  • 2 cm
A plane mirror is placed at the bottom of a tank containing a liquid of refractive index µ. P is a small object at a height h above the mirror. An observer O-vertically above P outside the liquid sees P and its image in the mirror. The apparent distance between these two will be
  • 2 µh
  • 2)
    Physics-Ray Optics-85563.png

  • Physics-Ray Optics-85564.png

  • Physics-Ray Optics-85565.png
A ray of light falls on a transparent sphere with centre at C as shown in Fig. The ray emerges from the sphere parallel to line AB. The refractive index of the sphere is
Physics-Ray Optics-85567.png

  • Physics-Ray Optics-85568.png
  • 2)
    Physics-Ray Optics-85569.png

  • Physics-Ray Optics-85570.png

  • Physics-Ray Optics-85571.png
One side of a glass slab is silvered as shown in Fig. A ray of light is incident on the other side at angle of incidence I = 45 0 . Refractive index of glass is 1.5. The deviation of the ray of light from its initial path when it comes out of the slab is
Physics-Ray Optics-85573.png
  • 180º
  • 120º
  • 45º
  • 90º
A watch glass has uniform thickness, and the average radius of curvature of its two surfaces is much larger than its thickness. It is placed in the path of a beam of parallel light. The beam will
  • diverge slightly
  • be completely unaffected
  • converge slightly
  • converge or diverge slightly depending on whether the beam is incident from the concave or the convex side
A beam of light, consisting of red, green and blue colours, is incident on a right – angled prism, as shown in Fig. The refractive indices of the material of the prism for the red, green and blue wavelengths are 1.39, 1.44 and 1.47 respectively. The prism will
Physics-Ray Optics-85575.png
  • separate part of the blue colour from the red and green colours
  • separate all the three colours from one another
  • not separate even partially, any colour from the other two colours
  • separate part of the red colour from the green and blue colours
nth bright fringe of red light (λ1 = 7500 Å ) Coincides with (n + 1)th bright fringe of green light (λ2 = 6000 Å ). The value of n = _____________.
  • 8
  • 4
  • 2
  • 1
The diagram below shows a light ray parallel to the principal axis of a spherical convex (diverging) mirror. point F is the virtual focal point of the mirror and C is the centre of curvature. After the light ray is reflected, it will pass through point
Physics-Ray Optics-85578.png
  • A
  • C
  • D
  • F
Statement I The formula connecting u, v and f for a spherical minor is valid only for mirrors whose sizes are very small compared to their radii of curvature.
Statement II Laws of reflection are strictly valid for plane surfaces, but not for large spherical surfaces.
  • Statement I is correct. Statement II is correct; Statement II is a correct explanation for Statement I
  • Statement I is correct, Statement II is correct; Statement II is not a correct explanation for Statement I
  • Statement I is correct, Statement II is incorrect
  • Statement I is incorrect, Statement II is correct

Physics-Ray Optics-85579.png

  • Physics-Ray Optics-85580.png
  • 2)
    Physics-Ray Optics-85581.png

  • Physics-Ray Optics-85582.png

  • Physics-Ray Optics-85583.png
A green light is incident from the water to the air-water interface at the critical angle (θ). Select the correct statement.
  • The entire spectrum of visible light will come of the water at an angle of 90° to the normal.
  • The spectrum of visible light whose frequency is less than that of green light will come out of the air medium.
  • The spectrum of visible light whose frequency is more than that of green light will come out to the air medium.
  • The entire spectrum of visible light will come out of the water of various angles to the normal.

Physics-Ray Optics-85585.png
  • The ray gets totally internally reflected at face CD
  • The ray comes out through face AD
  • The angle between the incident ray and the emergent ray is 90°
  • The angle between the incident ray and the emergent ray is 120°
  • All 1,2 and 3

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  • 2)
    Physics-Ray Optics-85588.png

  • Physics-Ray Optics-85589.png

  • Physics-Ray Optics-85590.png

Physics-Ray Optics-85592.png
  • 30°
  • 45°
  • 60°

  • Physics-Ray Optics-85593.png
A ray of light travelling 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 reflected ray and no reflected ray
  • a reflected ray and a refracted ray and the angle between then would be less than 180° – 2θ
  • a reflected ray and a refracted ray and the angle between then would be greater than 180° – 2θ
An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and the eye piece is 36 cm and the final image is formed at infinity. The focal length fo of the objective and the focal length fe of the eye piece are
  • fo = 45 cm and fe = – 9 cm
  • fo = – 7.2 cm and fe = 5 cm
  • fo = 50 cm and fe = 10 cm
  • fo = 30 cm and fe = 6 cm
Statement (I) Using Huygen's eye piece measurements can be taken but are not correct.
Statement (II) The cross wires, scale and final image are not magnified proportionately because the image of the object is magnified be two lenses, whereas the cross wire scale is magnified by one lens only.
Identify the correct one of the following
  • Both Statement I and Statement II are correct, Statement II is the correct explanation of Statement I.
  • Both Statement I and Statement II are correct, but Statement II is incorrect explanation of Statement I.
  • Only Statement I is correct, but Statement II is incorrect.
  • Both Statement I and Statement II are incorrect.
At Kavalur in India, the astronomers using a telescope whose objective had a diameter of one metre started using telescope of diameter 2.54 m. This resulted in
  • the increase in the resolving power by 2.54 times for the same λ
  • the increase in the limiting angle by 2.54 times for the same λ
  • decrease in the resolving power
  • no effect on the limiting angle

Physics-Ray Optics-85595.png
  • 45°
  • 60°
  • 75°
  • 30°
The graph between u and v for a convex mirror is

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  • 2)
    Physics-Ray Optics-86563.png

  • Physics-Ray Optics-86564.png

  • Physics-Ray Optics-86565.png
A beaker contains water, up to a height h1 and kerosene of height h2 above water, so that the total height of (water + kerosene) is (h1 + h2 ). Refractive index of water is µ1 and that of kerosene is µ2. The apparent shift in the position of the bottom of the beaker when viewed from above is

  • Physics-Ray Optics-85597.png
  • 2)
    Physics-Ray Optics-85598.png

  • Physics-Ray Optics-85599.png

  • Physics-Ray Optics-85600.png

Physics-Ray Optics-85601.png
  • 6 cm
  • 7 cm
  • 8 cm
  • 9 cm
A, B and C are the parallel sided transparent media of refractive indices n1 , n2 and n3respectively. They are arranged as shown in the figure. A ray is incident at an angle i on the surface of separation of A and B which is as shown in the figure. After the refraction into the medium B, the ray grazes the surface of separation of the media B and C. Then, sin i equal to
Physics-Ray Optics-85602.png

  • Physics-Ray Optics-85603.png
  • 2)
    Physics-Ray Optics-85604.png

  • Physics-Ray Optics-85605.png

  • Physics-Ray Optics-85606.png
A beam of light composed of red and green rays is incident obliquely at a point on the face of a rectangular glass slab. When coming out on the opposite parallel face, the red and green rays emerge from
  • two points propagating in two different non-parallel directions
  • two point propagating in two different parallel directions
  • one point propagating in two different directions
  • one point propagating in the same direction
Four combinations of two thin lenses are given in column I. The radius of curvature of all curved surfaces is r and the refractive index of all the lenses is 1.5. Match lens combinations in column I with their focal length in column II and select the correct answer using the code given below the lists.
Physics-Ray Optics-85607.png
  • P = 1, Q = 2, R = 3, S = 4
  • P = 2, Q = 4, R = 3, S = 1
  • P = 4, Q = 1, R = 2, S = 3
  • P = 2, Q = 1, R = 3, S = 4
A bi-convex lens is formed with two thin plano-convex lenses as shown in the figure. Refractive index n of the first lens is 1.5 and that of the second lens is 1.2. Both the curved surfaces are of the same radius of curvature R = 14 cm. For this bi-convex lens, for an object distance of 40 cm, the image distance will be
Physics-Ray Optics-85608.png
  • – 280.0 cm
  • 40.0 cm
  • 21.5 cm
  • 13.3 cm
A planoconvex lens has a maximum thickness of 6 cm. When placed on a horizontal table with the curved surface in contact with the table surface, the apparent depth of the bottom most point of the lens is found to be 4 cm. If the lens is inverted such that the plane face of the lens is in contact with the surface of the table, the apparent depth of the centre of the plane face is found to be (17/cm. The radius of curvature of the lens is
  • 34 cm
  • 128 cm
  • 75 cm
  • 68 cm

Physics-Ray Optics-85609.png
  • 2/3 < sin θ < 8/9
  • sin θ ≤ 2/3
  • cos θ ≥ 8/9
  • sin θ > 8/ 9
  • cos θ ≤ 8/9
0:0:1


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