Ray Optics and Optical Instruments

CBSE Class 12 Physics · every board question from this chapter, 2022–2026 · 61 of them repeated across years

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A ray of monochromatic light travelling in air is incident on a glass slab and is partly reflected and partly refracted. Both the…2026
An equiconvex lens of focal length 15 cm is cut into two equal plano-convex halves. The focal length of each half will be: 30 cm…2026
A thin plano-convex lens and a thin equi-concave lens are kept coaxially in contact as shown in the figure. Assuming both the…2026asked 3×
A concave lens of focal length 40 cm is coaxially in contact with two convex lenses, each of focal length 20 cm, on each side.…2026
A plano-convex lens, made of glass (n=1 · 5) has a curved surface whose radius is 40 cm. The image formed of an object is of the…2026
A telescope has an objective lens of focal length 144 cm and an eyepiece of focal length 6.0 cm. The magnifying power and the…2026
Light from a small object in air falls on a spherical glass surface (n=1.5) of radius of curvature R. A real image of the object…2026
In which of the following, total internal reflection does not occur?2026
A concave lens of focal length 10 cm is cut into two identical plano-concave lenses. The focal length of each lens will be2026
A ray of yellow light undergoes total internal reflection when it is incident at the interface of two media. This ray is…2026
Assertion: When a convex lens made of glass is immersed in water, its converging power increases. Reason (R): The focal length of…2026asked 3×
A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled…2026
A small bulb is placed at the bottom of a tank, containing a transparent liquid of refractive index √2, to a depth of 1 m.…2026
A ray of light is incident on the face of a triangular prism of refracting angle 60° and it just suffers total internal…2026
A tank is filled with a liquid to a height of 12 · 5 m. The apparent depth of a needle lying at the bottom of the tank is…2026
A ray of light in air is incident at angle ∠i on a face of an equilateral glass prism and is refracted through the prism. As ∠ i…2026
When monochromatic light is incident on a surface separating two media, the refracted and reflected light both have the same…2026
A concave mirror of radius of curvature 16 cm produces two-times enlarged real image of an object kept in front of it. Find the…2026
A convex lens of refractive index 1.5 has a focal length of 20 cm in air. Find its nature and focal length when it is immersed in…2026
Two thin lenses of focal length f 1 and f 2 are placed in contact with each other coaxially. Prove that the focal length f of the…2026
Draw a labelled ray diagram of an astronomical telescope when final image is formed at infinity. Write the expression for its…2026
A point source, in air, is placed at a distance of 6 cm in front of a convex spherical surface ( n=1 · 5 and radius of curvature…2026
A 5 cm long pencil is placed along the principal axis of a concave mirror of focal length 20 cm such that its nearest end is at a…2026asked 3×
A ray of light is incident at an angle 2A on one of the faces of a glass prism of refracting angle A. After refraction from this…2026
A ray of light is incident at angle of 45° on one face of a prism with an equilateral triangular base. If it passes symmetrically…2026
Define the term 'critical angle'. A small bulb is placed at the bottom of a tank containing a liquid of refractive index μ at a…2026
A ray of light is travelling through a rectangular glass slab (refractive index 3/2 ) and is incident on the horizontal glass-air…2026
Draw the ray diagram to show the image formation by a refracting telescope and write the expression for angular magnification for…2026
Why does one prefer to view the image formed at infinity than that formed at near point in microscope/telescope? Consider lenses…2026
State the two conditions under which total internal reflection occurs. A transparent container contains layers of three…2026asked 3×
Draw a labelled ray diagram showing the formation of image by a compound microscope when final image is formed at least distance…2026
An astronomical telescope consists of two converging lenses. One of them of large aperture and large focal length is called…2026asked 3×
In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves…2026asked 3×
(i) Define refractive index of a medium in terms of speed of light. (ii) Derive the relation for the refractive index ( μ ) of a…2026asked 3×
Using the relation for refraction at a curved spherical surface, derive the expression for lens maker's formula. Three lenses L…2026asked 3×
(i) A point object is kept in front of a convex spherical surface of radius of curvature R. Draw the ray diagram to show the…2026asked 3×
(i) A parallel beam of monochromatic light falls normally on a single slit of width 'a' and a diffraction pattern is observed on…2026asked 3×
A beaker is filled with water (refractive index 4/3 ) upto a height H. A coin is placed at its bottom. The depth of the coin,…2025
The speed of light in two media' 1 'and' 2 'are v 1 and v 2( v 1) respectively. For a ray of light to undergo total internal…2025
A point source is placed at the bottom of a tank containing a transparent liquid (refractive index n ) to a depth H. The area of…2025
The magnification produced by a spherical mirror is -2 · 0. The mirror used and the nature of the image formed will be2025asked 3×
A tub is filled with a transparent liquid to a height of 30.0 cm. The apparent depth of a coin lying at the bottom of the tub is…2025
The focal length of a concave mirror in air is f. When the mirror is immersed in a liquid of refractive index 5/3, its focal…2025
The plane face of a planoconvex lens is silvered. The refractive index of material and radius of curvature of the curved surface…2025
A compound microscope has an objective and an eyepiece of focal lengths f 0 and f e, respectively. To obtain a large…2025
A glass slab (μ=1 · 5) of thickness 6 cm is placed over a paper. The shift in the letters printed on the paper will be:2025
Assertion: In a reflecting telescope, the image does not have chromatic aberration. Reason (R): Chromatic aberration occurs only…2025asked 3×
Assertion: A ray of light is incident normally on the face of a prism. The emergent ray will graze along the opposite face of the…2025asked 3×
A point object is placed in air at a distance R / 3 in front of a convex surface of radius of curvature R, separating air from a…2025asked 3×
Using the mirror equation and the formula of magnification, deduce that "the virtual image produced by a convex mirror is always…2025asked 3×
Two convex lenses A and B, each of focal length 10.0 cm, are mounted on an optical bench at 50.0 cm and 70.0 cm respectively. An…2025
The two surfaces of a biconvex lens are of radius of curvature ' R ' each. Obtain the condition under which its focal length ' f…2025
Find the focal length of plano-convex lens of refractive index 1.5 and radius of curvature 10 cm when it is immersed in a liquid…2025
A spherical convex surface of radius of curvature R separates glass (refractive index 1.5) from air. Light from a point source…2025
A transparent solid cylindrical rod (refractive index 2/(√3) ) is kept in air. A ray of light incident on its face travels along…2025
An equiconvex lens is made of glass of refractive index 1.55. If the focal length of the lens is 15 · 0 cm, calculate the radius…2025
Two concave lenses A and B, each of focal length 8.0 cm are arranged coaxially 16 cm apart as shown in figure. An object P is…2025
A double convex lens of glass has both faces of the same radius of curvature 17 cm. Find its focal length if it is immersed in…2025
A light beam converges at a point O. In the path of this beam, a concave lens of focal length 15 cm is placed at a distance of 10…2025
A right angled isosceles glass prism ABC is kept in contact with an equilateral triangular prism DBC as shown in the figure. Both…2025
A ray of light is incident on face AB of a prism ABC with angle of prism A and emerges out from face AC. The prism is set in the…2025
A tank is filled with a liquid of refractive index √2, up to a height of 30 cm. A tiny bulb is glowing at the bottom of the tank.…2025
A ray of light is incident at an angle i on a parallel sided glass slab of thickness' d 'and gets refracted into the slab at…2025
A right-angled prism ABC (refractive index √2 ) is kept on a plane mirror as shown in the figure. A ray of light is incident…2025
A concave mirror has radius of curvature 20 cm. Calculate the distance of an object from the mirror so as to form an image of…2025
An air bubble is trapped at point P(CP=1 · 75 cm) in a spherical glass ball ( n=1 · 5 ) of radius 7 cm as shown in the figure.…2025
When a parallel beam of light enters water surface obliquely at some angle, what is the effect on the width of the beam? With the…2025asked 3×
Draw a ray diagram showing the image formation when a concave mirror produces a real, inverted and magnified image of an object…2025
A rectangular glass slab ABCD (refractive index 1.5) is surrounded by a transparent liquid (refractive index 1.25) as shown in…2025
A thin lens is a transparent optical medium bounded by two surfaces, at least one of which should be spherical. Applying the…2025
When light travels from an optically denser medium to an optically rarer medium, at the interface it is partly reflected back…2025
When light travels from an optically denser medium to an optically rarer medium, at the interface it is partly reflected back…2025asked 2×
(i) An object is placed 30 cm from a thin convex lens of focal length 10 cm. The lens forms a sharp image on a screen. If a thin…2025asked 3×
(i) Draw a ray diagram to show the image formation by a compound microscope. Obtain the expression for the total magnification of…2025asked 3×
(i) Draw a ray diagram of a reflecting telescope (Cassegrain) and explain the formation of image. State two important advantages…2025asked 3×
(i) Explain with the help of a labelled ray diagram the formation of final image by an astronomical telescope at infinity. Write…2025asked 3×
(i) A thin pencil of length ( f / 4 ) is placed coinciding with the principal axis of a mirror of focal length f. The image of…2025asked 3×
The focal lengths of the objective and the eyepiece of a compound microscope are 1 cm and 2 cm respectively. If the tube length…2024asked 3×
A point object is kept 60 cm in front of a spherical convex surface ( n=1.5, radius of curvature 40 cm ). The image formed is2024
Assertion: A convex lens, when immersed in a liquid, disappears. Reason ( R ): The refractive indices of material of the lens and…2024asked 3×
Assertion: The magnifying power of a compound microscope is negative. Reason (R): The final image formed is erect with respect to…2024asked 3×
Assertion: Plane and convex mirrors cannot produce real images under any circumstance. Reason ( R ): A virtual image cannot serve…2024asked 3×
The magnifying power of an astronomical telescope is 24. In normal adjustment, distance between its two lenses is 150 cm. Find…2024asked 3×
Monochromatic light of frequency 5.0 × 10^14 Hz passes from air into a medium of refractive index 1 · 5. Find the wavelength of…2024asked 3×
A convex lens (n = 1.52) has a focal length of 15.0 cm in air. Find its focal length when it is immersed in liquid of refractive…2024asked 3×
A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm. Calculate its magnifying power in…2024
A thin converging lens of focal length 10 cm is placed coaxially in contact with a thin diverging lens of focal length 15 cm. How…2024
Explain the following: For a simple microscope, the angular size of the object equals the angular size of the image. Yet it…2024
A ray of light is incident normally on one face of an equilateral glass prism of refractive index μ. When the prism is completely…2024asked 3×
The radius of curvature of a convex mirror is 30 cm. It forms an image of an object which is half the size of the object. Find…2024
An object is placed 30 cm in front of a concave mirror of radius of curvature 40 cm. Find the (i) position of the image formed…2024asked 3×
An air bubble is trapped at point B(CB=20 cm) in a glass sphere of radius 40 cm and refractive index 1.5 as shown in figure. Find…2024asked 3×
A lens is a transparent medium bounded by two surfaces, with one or both surfaces being spherical. The focal length of a lens is…2024asked 3×
A lens is a transparent optical medium bounded by two surfaces; at least one of which should be spherical. Applying the formula…2024asked 3×
A prism is an optical medium bounded by three refracting plane surfaces. A ray of light suffers successive refractions on passing…2024asked 3×
When a ray of light propagates from a denser medium to a rarer medium, it bends away from the normal. When the incident angle is…2024asked 3×
(i) Draw a ray diagram for the formation of the image of an object by a convex mirror. Hence, obtain the mirror equation. (ii)…2024asked 3×
(i) Trace the path of a ray of light showing refraction through a triangular prism and hence obtain an expression for angle of…2024asked 3×
(i) A ray of light passes through a triangular prism. Show graphically, how the angle of deviation varies with the angle of…2024asked 3×
The minimum distance between an object and its real image formed by a convex lens of focal length f is:2023
A ray of monochromatic light propagating in air, is incident on the surface of water. Which of the following will be the same for…2023asked 3×
A beam of light travels from air into a medium. Its speed and wavelength in the medium are 1.5 × 10^8 ms^-1 and 230 nm…2023
For a concave mirror of focal length ' f ', the minimum distance between the object and its real image is:2023
A plane wavefront is incident on a concave mirror of radius of curvature R. The radius of the refracted wavefront will be:2023asked 3×
A ray of light travels a distance of 12.0 m in a transparent sheet in 60 ns. The refractive index of the sheet is2023
Which of the following pairs of media has the least value of critical angle?2023
A ray of light of wavelength 600 nm propagates from air into a medium. If its wavelength in the medium becomes 400 nm, the…2023
The radii of curvature of the faces of a double-convex lens are 20 cm and 30 cm. Its power is 25/6 D. What is the refractive…2023
Using Huygens' principle, draw a ray diagram showing the propagation of a plane wave refracting at a plane surface separating two…2023asked 3×
In the given figure the radius of curvature of curved face in the plano- convex and the plano-concave lens is 15 cm each. The…2023
The refractive indices of two media A and B are 2 and √2 respectively. What is the critical angle for their interface?2023asked 3×
The power of a thin lens is +5 D. When it is immersed in a liquid, it behaves like a concave lens of focal length 100 cm.…2023
A double-convex lens of power 4 D is manufactured from a glass of refractive index 1 · 5. What is the radius of curvature of each…2023
A point object in air is placed symmetrically at a distance of 60 cm in front of a concave spherical surface of refractive index…2023
A ray of light is refracted by a glass prism. Obtain an expression for the refractive index of the glass in terms of the angle of…2023
A ray of light is incident on a glass prism of refractive index μ and refracting angle A. If it just suffers total internal…2023
Define critical angle for a given pair of media and total internal reflection. Obtain the relation between the critical angle and…2023
(i) (1) Write two points of difference between an interference pattern and a diffraction pattern. (2) Name any two factors on…2023asked 3×
(i) Draw a ray diagram to show how the final image is formed at infinity in an astronomical refracting telescope. Obtain an…2023asked 3×
(i) Draw a ray diagram to show the working of a compound microscope. Obtain the expression for the total magnification for the…2023asked 3×
(i) Draw a ray diagram showing the formation of a real image of an object placed at a distance ' u ' in front of a concave mirror…2023asked 3×
(i) State Huygen's principle. With the help of a diagram, show how a plane wave is reflected from a surface. Hence verify the law…2023asked 3×
A lens is a transparent optical medium bounded by two surfaces; at least one of which should be spherical. Considering image…2023asked 3×
Strontium titanate is a rare oxide - a natural mineral found in Siberia. It is used as a substitute for diamond because its…2023asked 3×
The lens maker's formula is useful to design lenses of desired focal lengths using surfaces of suitable radii of curvature. The…2023asked 3×
A point source in air is kept 24 cm in front of a concave spherical glass surface ( a μ g=1.5) and radius of curvature 60 cm.…2022
State the conditions for total internal reflection to take place. A tank is filled with a transparent liquid to height 'H'. A…2022
With the help of a ray diagram, show how a compound microscope forms a magnified image of a tiny object, at least distance of…2022
Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal adjustment.…2022asked 3×
An equiconvex lens forms a two times enlarged real image when an object is kept 16 cm from it. The lens is cut into two identical…2022
Explain with the help of a suitable diagram, the phenomenon on which an optical fibre works. Mention any two uses of optical…2022asked 2×
A ray is incident on a prism of material of refractive index √2 at point M such that it grazes along NC after emerging from the…2022
A converging lens made of glass (μ=1 · 5) has its spherical faces of radii of curvature 10 cm and 20 cm. Find its focal length in…2022
(i) Draw a labelled ray diagram showing the formation of the image at infinity by an astronomical telescope. (ii) A telescope…2022asked 3×
Write two necessary conditions for total internal reflection. Two prisms ABC and DBC are arranged as shown in figure. The…2022asked 3×
(i) Define SI unit of power of a lens. (ii) A plano convex lens is made of glass of refractive index 1.5. The radius of curvature…2022asked 3×
Find the two possible positions of an object kept in front of a lens of +5.0 D, so that the image formed in both cases is four…2022
A ray of light passes through a prism of refractive index √2 as shown in the figure. Find: (i) The angle of incidence (∠ r 2) at…2022asked 3×
A ray of light is incident on a prism at an angle of 45° and passes symmetrically as shown in the figure. Calculate: the angle of…2022
Is the speed of light in glass independent of the colour of light? Give reason. A small bulb is placed at the bottom of a tank…2022
The figure shows a water column BCFE surrounded by two media (1) and (3) of the same refractive index √2. A ray of light from a…2022
A diver looking up through water (μ=4/3) sees the outside world contained in a circular area on the surface of water. If the…2022
The refractive index of an equilateral triangular prism kept in air is √2. Calculate: the angle of minimum deviation. the…2022
For a glass prism of refractive index √3, the value of angle of minimum deviation δ is equal to the angle of prism A. Find the…2022
(i) Monochromatic light is incident on a surface separating two media. The frequency of the light after refraction remains…2022asked 3×
Two transparent media of refractive indices n 1 and n 2 are separated by a spherical transparent surface. The rays of light…2022asked 3×
A ray of light travels from a denser to a rarer medium. After refraction, it bends away from the normal. When we keep increasing…2022asked 3×
A compound microscope consists of two converging lenses. One of them, of smaller aperture and smaller focal length is called…2022asked 3×

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