JEE Questions for Physics Ray Optics Quiz 2 - MCQExams.com

The angle of a prism is 42° and refractive index of its material is 3/2. Then, angle of minimum deviation for this prism is
  • 63°
  • 42°
  • 28°
  • 21°
Object is placed at a distance 10 cm from a convex mirror of focal length 20 cm. Image distance is
  • 20/3 cm
  • 3/20 cm
  • 4 cm
  • 4.5 cm
The image of an electric bulb fixed in a wall is to be obtained on the wall opposite to it at a distance of 3 m. The maximum possible focal length of the convex lens is
  • 3.25 cm
  • 1.55 cm
  • 0.75 cm
  • 0.25 cm
When monochromatic red light is used instead of blue light in a convex lens. its focal length will
  • does not depend on colour of light
  • increase
  • decrease
  • remain same
Two thin lenses of focal length 20 cm and 25 cm are placed in contact. The effective power of the combination is
  • 9 D
  • 2 D
  • 3 D
  • 7 D
A convex lens of focal length 30 cm produces 5 times magnified real image of an object. What is the object distance?
  • 36 cm
  • 25 cm
  • 30 cm
  • 150 cm
A plano-concave lens is made of glass of refractive index 1.5 and the radius of curvature of its curved face is 100 cm. What is the power of the lens?
  • + 0.5 D
  • – 0.5 D
  • – 2 D
  • + 2 D
A thin convex lens of crown glass having refractive index 1.5 has power 1 D. What will be the power of similar convex lens refractive index 1.6?
  • 0.6 D
  • 0.8 D
  • 1.2 D
  • 1.6 D
A convex lens made of glass has focal length 0.15 m in air. If the refractive index of glass is 3/2 and that of water is 4/3, the focal length of lens when immersed in water is
  • 0.45 m
  • 0.15 m
  • 0.30 m
  • 0.6 m
60° prism has μ = √2 . Angle of incidence for minimum deviation is
  • 45°
  • 30°
  • 60°
  • 90°
For a prism of refractive index 1.732, the angle of minimum deviation is equal to the angle of prism. Then, the angle of the prism is
  • 50°
  • 60°
  • 70°
  • None of these
A convex lens is immersed in a liquid, whose refractive index is equal to the refractive index of the material of the lens. Then its focal length will
  • decrease
  • become zero
  • become infinite
  • increase
When the light enters from air to glass, for which colour the angle of deviation is maximum?
  • Red
  • Yellow
  • Blue
  • Violet
A thin lens of glass (μ = 1.of focal length +10 cm is immersed in water (μ =1.33). The new focal length is
  • 20 cm
  • 40 cm
  • 48 cm
  • 12 cm
The refractive index of a material of a planoconcave lens is 5/3, the radius of curvature is 03 m. The focal length of the lens in air is
  • – 0.45 m
  • – 0.6 m
  • – 0.75 m
  • – 1.6 m
A convex and a concave lens separated by distance d are then put in contact. The focal length of the combination
  • decreases
  • increases
  • becomes zero
  • remains the same
Two lenses of power –15 D and + 5 D are in contact with each other. The focal length of the combination is
  • – 20 cm
  • – 10 cm
  • + 20 cm
  • + 10 cm
Two thin equiconvex lenses each of focal length 0.2 m are placed coaxially with their optic centres 0.5 m apart. Then, the focal length of the combination is
  • – 0.4 m
  • 0.4 m
  • – 0.1 m
  • 0.1 m
Two thin lenses of focal length 20 cm and 25 cm are in contact. The effective power of the combination is
  • 4.5 D
  • 18 D
  • 45 D
  • 9 D
The plano-convex lens of focal length 20 cm and 30 cm are placed together to form a double convex lens. The final focal length will be
  • 12 cm
  • 60 cm
  • 20 cm
  • 30 cm
A convex lens of focal length 10 cm and image formed by it, is at least distance of distinct vision then, the magnifying power is
  • 3.5
  • 2.5
  • 1.5
  • 1.4
If two +5 D, lenses are mounted at some distance apart, the equivalent power will always he negative, if the distance is
  • greater than 40 cm
  • equal to 10 cm
  • equal to 10 cm
  • less than 10 cm
An object is placed at 20 cm in front of a concave mirror produces three times magnified real image. What is the focal length of the concave mirror?
  • 15 cm
  • 6.6 cm
  • 10 cm
  • 7.5 cm
A concave mirror has a radius of curvature of 35 cm. It is positioned so that the (upright) image of the object is 2.5 times, the size of the object. How far is the mirror from the object?
  • 10.5 cm
  • 9.2 cm
  • 8.7 cm
  • 6.7 cm
The diagram below shows a ray of light travelling parallel to the principal axis of a concave spherical mirror. Point F is the principal focus and point C is the centre of curvature. After striking the minor, the ray of light will be reflected through. point
Physics-Ray Optics-85353.png
  • A
  • D
  • C
  • F
An experiment is performed to find the refractive index of glass using a travelling microscope. In this experiment distance are measured by
  • a vernier scale provided on the microscope
  • a standard laboratory scale
  • a meter scale provided on the microscope
  • a screw gauge provided on the microscope
When a student looks into a plane mirror, she sees a virtual image of herself. However, when she looks into a sheet of paper, no such image forms. Which light phenomenon occurs at the surface of the paper?
  • Regular reflection
  • Diffuse reflection
  • Polarization
  • Resonance
A concave mirror of focal length f produces a real image n times the size of the object. The distance of the object from the mirror is
  • (n –f
  • (n +f
  • (n +f/n
  • (n –f/n

Physics-Ray Optics-85355.png
  • 30°
  • 45°
  • 60°
  • 75°
A light ray travelling in glass medium is incident on glass-air interface at an angle of incidence θ. The reflected (R) and transmitted (T) intensities, both as function of θ, are platted. The correct sketch is

  • Physics-Ray Optics-85357.png
  • 2)
    Physics-Ray Optics-85358.png

  • Physics-Ray Optics-85359.png

  • Physics-Ray Optics-85360.png
A car is fitted with a convex side view mirror of focal length 20 cm. A second car 2.8 m behind the first car is overtaking the first car is a relative speed of 15 m/s. The speed of the image of the second car as seen in the mirror of the first one is
  • 1/15 m/s
  • 10 m/s
  • 15 m/s
  • 1/10 m/s

Physics-Ray Optics-85362.png
  • 3
  • 4
  • 5
  • 6
A square wire of side 1 cm is placed perpendicular to the principle axis of a concave mirror of focal length 15 cm at a distance of 20 cm. The area enclosed by the image of the wire is
  • 4 cm2
  • 6 cm2
  • 2 cm2
  • 8 cm2
  • 9 cm2
An object moving at a speed of 5 m/s towards a concave mirror of focal length f = 1 m is at a distance of 9 m. The average speed of the image is

  • Physics-Ray Optics-85364.png
  • 2)
    Physics-Ray Optics-85365.png

  • Physics-Ray Optics-85366.png

  • Physics-Ray Optics-85367.png
A person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face, the image becomes inverted. What type of mirror he is using?
  • Plane mirror
  • Convex mirror
  • Concave mirror
  • None of these
The radius of curvature of concave mirror is 24 cm and the image is magnified by 1.5 times. The object distance is
  • 20 cm
  • 8 cm
  • 16 cm
  • 24 cm
An object is placed at a distance of 40 cm in front of a concave mirror of focal length 20 cm. The nature of image is
  • real and inverted and of same size
  • virtual and erect and of same size
  • real and erect and of same size
  • virtual and inverted and of same size
An object is placed in front of a convex mirror of focal length f. Find the maximum and minimum distance of two object from the mirror such that the image is real and magnified.
  • 20 and ∞
  • f and 2f
  • f and 0
  • None of these
A ray of light is incident at 50° on the middle of one of the two mirrors arranged at an angle of 60° between them. The ray then touches the second mirror, gets reflected back to the first mirror, making an angle of incidence
  • 50°
  • 60°
  • 70°
  • 80°
Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror and parallel to the second is reflected from the second mirror parallel to the first mirror. The angle between the two mirrors is
  • 30°
  • 45°
  • 60°
  • 75°
In the figure, a ray of light is perpendicular to the face AB of a glass prism (µ =1.52). Find the value of θ, so that the ray is totally reflected at face AC, if the prism is immersed in water.
Physics-Ray Optics-85370.png
  • 45°
  • 30°
  • 15°
  • None of these
The refractive index of water is 4/3 and that of glass is 5/3. What will be critical angle for the ray of light entering water from the glass?

  • Physics-Ray Optics-85371.png
  • 2)
    Physics-Ray Optics-85372.png

  • Physics-Ray Optics-85373.png

  • Physics-Ray Optics-85374.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 (tan i )
  • tan-1 (sin i )
  • sin-1 (cot i )
  • cos-1 (tan i )
The refractive index of water and glycerine are 1.33 and 1.47 respectively. What is the critical angle for a light ray going from the latter to the former?
  • 60°48'
  • 64°48'
  • 74°48'
  • None of these
Assertion (A) Propagation of light through an optical fibre is due to total internal reflection taking place at the core-clad interface.
Reason (R) Refractive index of the material of the core of the optical fibre is greater than that of air.
  • Both A and R are correct and R is the correct explanation of A
  • Both A and R are correct but R is not the correct explanation of A
  • A is correct but R is incorrect
  • A is incorrect but R is correct
Blue colour of sea water is due to
  • interference of sunlight reflected from the water surface
  • scattering of sunlight by the water molecules
  • image of sky in water
  • refraction of sunlight
If the ratio of amounts of scattering of two light waves is 1 : 4, the ratio of their wavelengths is
  • 1 : 2
  • √2 : 1
  • 1 : √2
  • 1 : 1
  • 2 : 1
An achromatic combination of lenses produces
  • images in black and white
  • coloured images
  • images unaffected by variation of refractive index with wavelength
  • highly enlarged images are formed
Rising and setting sun appears to be reddish because
  • diffraction sends red rays to earth at these times
  • scattering due to dust particles and air molecules are responsible
  • refraction is responsible
  • polarisation is responsible
Red colour is used for danger signals because
  • it causes fear
  • it undergoes least scattering
  • it undergoes maximum scattering
  • it is in accordance with international convention
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