Ray Optics and Optical Instruments
92 JEE Physics previous year questions on Ray Optics and Optical Instruments — options free on every question; 9 include the answer & explanation free, the rest unlock with PYQ Pass.
A thin biconvex lens is prepared from the glass \((\mu =1.5)\) both curved surfaces of which have equal radii of 20 cm each. Left side surface of the lens is silvered from outside to make it reflecting. To have the position of image and object at the same place, the object should be placed, from the lens at a distance of _________ cm .
[JEE Main 2026, 8 Apr (Shift 2)]
10
For the biconvex lens:
\({f}_{L}=\frac{R}{2(\mu -1)}=\frac{20}{2(1.5-1)}=20cm\)
For the silvered left surface, the mirror focal length is
\({f}_{m}=\frac{R}{2}=-10cm\)
For lens plus mirror combination:
\(\frac{1}{f}=\frac{1}{{f}_{m}}-\frac{2}{{f}_{L}}\)
\(\frac{1}{f}=-\frac{1}{10}-\frac{2}{20}=-\frac{1}{5}\)
\(f=-5cm\)
For the image to coincide with the object, the object must be at the center of curvature of the equivalent mirror system:
\(u=2|f|=10cm\)
A convex lens made of glass (refractive index = 1.5 ) has focal length 24 cm in air. When it is totally immersed in water (refractive index = 1.33 ), its focal length changes to:
\(96cm\)
The focal length in air is given by the lens formula:
\(\frac{1}{f}=\left({\mu }_{l}-1\right)\left(\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}\right)\)
where \(\mu\), is the refractive index of the lens material ( 1.5 for glass), and \({R}_{1}\) and \({R}_{2}\) are the radii of curvature of the lens surfaces. For air, the focal length f = 24 cm, So, \(\frac{1}{24}=(1.5-1)\cdot \left(\frac{2}{R}\right)\)
When immersed in water.
\(\frac{1}{{f}^{'}}=\left(\frac{{\mu }_{l}}{{\mu }_{s}}-1\right)\left(\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}\right)\)
Substituting the values for \({\mu }_{l}=1.5\), \({\mu }_{s}=1.33\) and the same \({R}_{1},{R}_{2}\) from before:
\(\frac{1}{{f}^{'}}=\left(\frac{1.5}{1.33}-1\right)\left(\frac{2}{R}\right)\)
Dividing the two equations for the focal lengths in air and in water, we get:
\(\frac{{f}^{'}}{24}=\frac{\left(1.5-1\right)}{\left(\frac{1.5}{1.33}-1\right)}\\ f'=96cm\)
Thus, the new focal length in water is:
\({f}^{'}=96cm\)
A lens having refractive index 1.6 has focal length of 12 cm, when it is in air. Find the focal length of the lens when it is placed in water. (Take refractive index of water as 1.28)
[JEE Main 2025, 7 Apr (Shift 1)]
\(288\mathrm{mm}\)
As we know the lens maker formula in a medium is given by
\(\frac{1}{f}=[\frac{{\mu }_{L}}{{\mu }_{m}}-1][\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}]\)
For air, refractive index of medium is unity
\({\mu }_{m}=1\)
Substituting values for air
\(\frac{1}{12}=[1.6-1][\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}]\)
Simplifying
\(\frac{1}{12}=\frac{6}{10}[\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}]\)
Hence
\([\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}]=\frac{10}{72}\)
For water as surrounding medium
\(\frac{1}{f}=[\frac{1.6}{1.28}-1][\frac{10}{72}]\)
Simplifying refractive index term
\(\frac{1}{f}=\frac{32}{128}\times \frac{10}{72}\)
\(\frac{1}{f}=\frac{1}{4}\times \frac{10}{72}\)
\(f=28.8\) cm
\(f=288\) mm
What is the relative decrease in focal length of a lens for an increase in optical power by 0.1 D from 2.5D? ['D' stands for dioptre]
[JEE Main 2025, 24 Jan (Shift 1)]
0.04
The focal length F is the reciprocal of optical power P :
\(F=\frac{1}{P}\)
When P =2.5 D,
\(F=\frac{1}{2.5}=\frac{2}{5}\)
When P increases to 2.6 D ,
\({F}^{'}=\frac{1}{2.6}=\frac{5}{13}\)
Relative decrease in focal length:
\(\frac{F-{F}^{'}}{F}=\frac{\frac{2}{5}-\frac{5}{13}}{\frac{2}{5}}\)
Simplifying:
\(=\frac{26-25}{26}=\frac{1}{26}\approx 0.04\)
the correct answer is 0.04 .
Given is a thin convex lens of glass (refractive index \(\mu\) ) and each side having radius of curvature \(R\). One side is polished for complete reflection. At what distance from the lens, an object be placed on the optic axis so that the image gets formed on the object itself ?
\(R/(2\mu -1)\)
\(\text{ (b) }{P}_{eq}=2{P}_{l}+{P}_{m}\\ -\frac{1}{{f}_{eq}}=\frac{2}{{f}_{ℓ}}-\frac{1}{{f}_{m}}\\ =\frac{4(\mu -1)}{R}-\frac{2}{-R}=\frac{1}{R}(4\mu -4+2)\\ -\frac{1}{{f}_{eq}}=\frac{1}{R}(4\mu -2)\\ \Rightarrow \frac{1}{{f}_{eq}}=\frac{-1}{R}(4\mu -2)\\ {f}_{eq}=\frac{R}{2}\\ R=2{f}_{eq}=2\left(\frac{R}{4\mu -2}\right)=\frac{R}{(2\mu -1)}\)
A plano-convex lens having radius of curvature of first surface 2 cm exhibits focal length of \({f}_{1}\) in air. Another plano-convex lens with first surface radius of curvature 3 cm has focal length of \({f}_{2}\) when it is immersed in a liquid of refractive index 1.2 . If both the lenses are made of same glass of refractive index 1.5 , the ratio of \({f}_{1}\) and \({f}_{2}\) will be:
\(1:3\)
Using the lens maker's formula
\(\frac{1}{{f}_{1}}=\left({n}_{\text{glass }}-{n}_{\text{air }}\right)\left(\frac{1}{{R}_{1}}-\frac{1}{{R}_{2}}\right)\)
Since one surface is flat, \({R}_{2}\) is infinity, so
\(\frac{1}{{R}_{2}}=0\)
For the first lens in air (with refractive index 1.5 and radius of curvature 2 cm ):
\(\frac{1}{{f}_{1}}=(1.5-1)\left(\frac{1}{2}\right)\\ {f}_{1}=4cm\)
For the second lens:
\(\frac{1}{{f}_{2}}=\left(\frac{1.5}{1.2}-1\right)\left(\frac{1}{3}-0\right)\\ {f}_{2}=12cm\)
Ratio of focal lengths:
\({f}_{1}:{f}_{2}=4:12=1:3\)
A thin convex lens of focal length 5 cm and a thin concave lens of focal length 4 cm are combined together (without any gap) and this combination has magnification m1 when an object is placed 10 cm before the convex lens. Keeping the positions of convex lens and object undisturbed, a gap of 1 cm is introduced between the lenses by moving the concave lens away, which lead to a change in magnification of total lens system to m2. The value of \(\left|\frac{{m}_{1}}{{m}_{2}}\right|\) is ____.
\(\frac{5}{6}\)
In Case-1: image is formed at \(\frac{20}{3}\) cm from combination
\(\Rightarrow \left|{m}_{1}\right|=\frac{20/3}{10}=\frac{2}{3}\)
In Case-2: Image formed at \(\frac{36}{5}\) cm from concave lens
\(\Rightarrow \left|{m}_{\text{concave}}\right|=\frac{36/5}{9}=\frac{4}{5}\)
\(\left|{m}_{\text{convex}}\right|=1\)
\(\Rightarrow \left|{m}_{2}\right|=\frac{4}{5}\)
\(\frac{\left|{m}_{1}\right|}{\left|{m}_{2}\right|}=\frac{5}{6}\)
A concave mirror of focal length \(f\) in air is dipped in a liquid of refractive index \(\mu\). Its focal length in the liquid will be:
[JEE Main 2025, 23 Jan (Shift 2)]
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Given a convex lens of refractive index \({\mu }_{2}\) in a liquid of refractive index \({\mu }_{1},{\mu }_{1}<{\mu }_{2}\) having radii of curvature \({\mathrm{R}}_{1},{\mathrm{R}}_{2}\mathrm{and}{\mathrm{R}}_{2}\) surface is silver polished. Where should an object be placed on the optical axis so that the real and inverted image is formed at the same place.
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A thin prism with angle 5° of refractive index 1.72 is combined with another prism of refractive index 1.9 to produce dispersion without deviation. The angle of second prism is____.
[JEE Main 2026, 22 Jan (Shift 2)]
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For a concave mirror, the distance between the object and image is 20 cm , and the magnification is -3 . Find the focal length of the mirror.
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Angle of minimum deviation is equal to the half of the angle of prism in an equilateral prism. The refractive index of the prism is _______.
[JEE Main 2026, 6 Apr (Shift 2)]
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The refractive index of the material of a glass prism is \(\sqrt{3}\). The angle of minimum deviation is equal to the angle of the prism. What is the angle of the prism?
[JEE Main 2025, 23 Jan (Shift 2)]
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If angle of prism is equal to the angle of minimum deviation. Given \(\mu =\sqrt{3}\), then find the angle of prism.
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When an object is placed 40 cm away from a spherical mirror an image of magnification \(\frac{1}{2}\) produced. To obtain an image with magnification of \(\frac{1}{3}\), the object is to be moved :
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A bi-convex lens has radius of curvature of both the surfaces same as\(1/6\mathrm{cm}\). If this lens is required to be replaced by another convex lens having different radii of curvatures on both sides \(\left({\mathrm{R}}_{1}\neq {\mathrm{R}}_{2}\right)\), without any change in lens power then possible combination of \({R}_{1}\) and \({R}_{2}\) is :
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A bi-convex lens has radius of curvature of both the surfaces same as\(1/6\mathrm{cm}\). If this lens is required to be replaced by another convex lens having different radii of curvatures on both sides \(\left({\mathrm{R}}_{1}\neq {\mathrm{R}}_{2}\right)\), without any change in lens power then possible combination of \({R}_{1}\) and \({R}_{2}\) is :
[JEE Main 2025, 2 Apr (Shift 2)]
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A convex lens is made from glass material having refractive index of 1.4 with same radius of curvature on both sides. The ratio of its focal length and radius of curvature is _______.
[JEE Main 2026, 4 Apr (Shift 2)]
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Distance between an object and three times magnified real image is 40 cm. The focal length of the mirror used is ____cm.
[JEE Main 2026, 24 Jan (Shift 2)]
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At the interface between two materials having refractive indices \({n}_{1}\) and \({n}_{2}\), the critical angle for reflection of an em wave is \({\theta }_{1C}\). The \({n}_{2}\) material is replaced by another material having refractive index \({n}_{3}\) such that the critical angle at the interface between \({n}_{1}\) and \({n}_{3}\) materials is \({\theta }_{2C}\). If \({n}_{3}>{n}_{2}>{n}_{1};\frac{{n}_{2}}{{n}_{3}}=\frac{2}{5}\) and \(\sin {\theta }_{2C}-\sin {\theta }_{1C}=\frac{–1}{2}\), then \({\theta }_{1C}\) is
[JEE Main 2025, 29 Jan (Shift 1)]
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A thin convex lens and a thin concave lens are kept in contact and co-axially. Which statement is correct?
[JEE Main 2026, 5 Apr (Shift 2)]
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What is the relative decrease in focal length of a lens for an increase in optical power by 0.1 D from 2.5D? ['D' stands for dioptre]
[JEE Main 2025, 24 Jan (Shift 1)]
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A monochromatic light of frequency \(5\times {10}^{14}\mathrm{Hz}\) travelling through air, is incident on a medium of refractive index '2'. Wavelength of the refracted light will be:
[JEE Main 2025, 3 Apr (Shift 2)]
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Given below are two statements :
Statement (I) : When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side.
Statement (II) : Concave lens always forms a virtual and erect image.
In the light of the above statements, choose the correct answer from the options given below :
[JEE Main 2024, 09 Apr (Shift 1)]
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Given below are two statements :
Statement (I) : When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side.
Statement (II) : Concave lens always forms a virtual and erect image.
In the light of the above statements, choose the correct answer from the options given below :
[JEE Main 2024, 09 Apr (Shift 1)]
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A thin prism \({P}_{1}\) with angle 4° made of glass having refractive index 1.54 , is combine with another thin prism \({P}_{2}\) made of glass having refractive index 1.72 to get dispersion without deviation. The angle of the prism \({P}_{2}\) in degrees is
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Given a thin convex lens (refractive index \(\mu_2\) ), kept in a liquid (refractive index \({\mu }_{1},{\mu }_{1}<{\mu }_{2}\) ) having radii of curvatures \(\left|{\mathrm{R}}_{1}\right|\) and \(\left|{\mathrm{R}}_{2}\right|\). Its second surface is silver polished. Where should an object be placed on the optic axis so that a real and inverted image is formed at the same place?
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A telescope with objective diameter R is used to observe a distant star emitting light of wavelength 500 nm , at a resolution of \(5\times {10}^{-7}\) radian. The value of R is_____ cm.
[04 April, 2026 (Shift-I)]
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At the interface between two materials having refractive indices \({n}_{1}\) and \({n}_{2}\), the critical angle for reflection of an em wave is \({\theta }_{1C}\). The \({n}_{2}\) material is replaced by another material having refractive index \({n}_{3}\) such that the critical angle at the interface between \({n}_{1}\) and \({n}_{3}\) materials is \({\theta }_{2C}\). If \({n}_{3}>{n}_{2}>{n}_{1};\frac{{n}_{2}}{{n}_{3}}=\frac{2}{5}\) and \(\sin {\theta }_{2C}-\sin {\theta }_{1C}=\frac{–1}{2}\), then \({\theta }_{1C}\) is:
[JEE Main 2025, 29 Jan (Shift 1)]
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If angle of prism is equal to the angle of minimum deviation. Given \(\mu =\sqrt{3}\), then find the angle of prism.
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Consider following statements for refraction of light through prism, when angle of deviation is minimum.
(A) The refracted ray inside prism becomes parallel to the base.
(B) Larger angle prisms provide smaller angle of minimum deviation.
(C) Angle of incidence and angle of emergence becomes equal.
(D) There are always two sets of angle of incidence for which deviation will be same except at minimum deviation setting.
(E) Angle of refraction becomes double of prism angle.
Choose the correct answer from the options given below.
[JEE Main 2025, 24 Apr (Shift 1)]
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Five persons \({P}_{1},{P}_{2},{P}_{3},{P}_{4}\) and \({P}_{5}\) recorded object distance (u) and image distance (v) using same convex lens having power +5 D as \((25,96),(30,62),(35,37),(45,35)\) and \((50,32)\) respectively. Identify correct statement.
[JEE Main 2026, 24 Jan (Shift 2)]
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A convex refracting surface curved towards medium A separates two media A and B, where medium A has a refractive index of 1.3 and medium B has a refractive index of 1.4. An object is placed 26 cm in medium A along the principal axis. If the image is formed at infinity, find the radius of curvature of the surface.
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A thin plano convex lens made of glass of refractive index 1.5 is immersed in a liquid of refractive index 1.2. When the plane side of the lens is silver coated for complete reflection, the lens immersed in the liquid behaves like a concave mirror of focal length 0.2 m. The radius of curvature of the curved surface of the lens is:
[JEE Main 2011]
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A plano-convex lens has a radius of curvature of 2 cm and a refractive index of 1.5. Its focal length is \({f}_{1}\) in air and \({f}_{2}\) in a medium with a refractive index of 1.2. Calculate the ratio \(\frac{{f}_{1}}{{f}_{2}}\).
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A plano-convex lens having radius of curvature of first surface 2 cm exhibits focal length of \({f}_{1}\) in air. Another plano-convex lens with first surface radius of curvature 3 cm has focal length of \({f}_{2}\) when it is immersed in a liquid of refractive index 1.2 . If both the lenses are made of same glass of refractive index 1.5 , the ratio of \({f}_{1}\) and \({f}_{2}\) will be
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A ray of light passing through an equilateral prism is having velocity \(2.12\times {10}^{8}\) m/s in the prism material, then the minimum angle of deviation is degrees.
[JEE Main 2026, 5 Apr (Shift 1)]
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A mirror is used to produce an image with magnification of \(\frac{1}{4}\). If the distance between object and its image is 40 cm , then the focal length of the mirror is ________ .
[JEE Main 2025, 7 Apr (Shift 2)]
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For a concave mirror, the distance between the object and image is 20 cm , and the magnification is -3 . Find the focal length of the mirror.
(Shift - II Memory Based)
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A convex lens of focal length 30 cm is placed in contact with a concave lens of focal length 20 cm . An object is placed at 20 cm to the left of this lens system. The distance of the image from the lens in cm is _____.
[JEE Main 2025, 8 Apr (Shift 1)]
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Distance between an object and three times magnified real image is 40 cm. The focal length of the mirror used is ____cm.
[JEE Main 2026, 24 Jan (Shift 2)]
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Critical angle of incidence for a pair of optical media is \(45^{\circ}\). The refractive indices of first and second media are in the ratio:
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For a thin symmetric prism made of glass (refractive index 1.5), the ratio of incident angle and minimum deviation will be______.
[JEE Main 2026, 2 Apr (Shift 1)]
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A convex refracting surface curved towards medium A separates two media A and B, where medium A has a refractive index of 1.3 and medium B has a refractive index of 1.4. An object is placed 26 cm in medium A along the principal axis. If the image is formed at infinity, find the radius of curvature of the surface.
(Shift - II Memory Based)
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A spherical surface of radius of curvature \(R\), separates air from glass (refractive index \(=1.5\) ). The centre of curvature is in the glass medium. A point object ' O ' placed in air on the optic axis of the surface, so that its real image is formed at ' I ' inside glass. The line OI intersects the spherical surface at P and \(\mathrm{PO}=\mathrm{PI}\). The distance PO equals to:
[JEE Main 2025, 23 Jan (Shift 1)]
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A concave-convex lens of refractive index \(1.5\) and the radii of curvature of its surfaces are \(30\) cm and \(20\) cm , respectively. The concave surface is upwards and is filled with a liquid of refractive index \(1.3\). The focal length of the liquid-glass combination will be:
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The wavelength of light, while it is passing through water is 540 nm. The refractive index of water is \(\frac{4}{3}\). The wavelength of the same light when it is passing through a transparent medium having refractive index of \(\frac{3}{2}\) is_______nm.
[JEE Main 2026, 22 Jan (Shift 2)]
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A concave mirror of focal length \(f\) in air is dipped in a liquid of refractive index \(\mu\). Its focal length in the liquid will be:
[JEE Main 2025, 23 Jan (Shift 2)]
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The wavelength of light, while it is passing through water is 540 nm. The refractive index of water is \(\frac{4}{3}\). The wavelength of the same light when it is passing through a transparent medium having refractive index of \(\frac{3}{2}\) is_______nm.
[JEE Main 2026, 22 Jan (Shift 2)]
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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A) : Refractive index of glass is higher than that of air.
Reason (R) : Optical density of a medium is directly proportionate to its mass density which results in a proportionate refractive index.
In the light of the above statements, choose the most appropriate answer from the options given below:
[JEE Main 2025, 7 Apr (Shift 2)]
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Given a thin convex lens (refractive index \(\mu_2\) ), kept in a liquid (refractive index \({\mu }_{1},{\mu }_{1}<{\mu }_{2}\) ) having radii of curvatures \(\left|{\mathrm{R}}_{1}\right|\) and \(\left|{\mathrm{R}}_{2}\right|\). Its second surface is silver polished. Where should an object be placed on the optic axis so that a real and inverted image is formed at the same place?
[JEE Main 2025, 23 Jan (Shift 1)]
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A plano-convex lens has a radius of curvature of 2 cm and a refractive index of 1.5. Its focal length is \({f}_{1}\) in air and \({f}_{2}\) in a medium with a refractive index of 1.2. Calculate the ratio \(\frac{{f}_{1}}{{f}_{2}}\).
(Shift - I Memory Based)
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Five persons P1, P2, P3, P4 and P5 recorded object distance (u) and image distance (v) using same convex lens having power +5D as (25, 96), (30, 62), (35, 37), (45, 35) and (50, 32) respectively. Identify correct statement.
[JEE Main 2026, 24 Jan (Shift 2)]
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What is the lateral shift of a ray refracted through a parallel-sided glass slab of thickness ' \(h\) ' in terms of the angle of incidence ' \(i\) ' and angle of refraction ' \(r\) ', if the glass slab is placed in air medium?
[JEE Main 2025, 23 Jan (Shift 1)]
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A thin prism \({P}_{1}\) with angle \(4^\circ\) made of glass having refractive index 1.45 , is combined with another thin prism \({P}_{2}\) made of glass having refractive index 1.60 to get dispersion without deviation. The angle of the prism \({P}_{2}\) in degrees is:
[JEE Main 2025, 28 Jan (Shift 1)]
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A compound microscope is designed with two symmetric biconvex lenses. The objective lens is cut vertically, creating two identical plano-convex lenses. One of them is used in place of original objective lens. To retain same magnification keeping the object distance unchanged, the tube length has to be:
[JEE Main 2026, 5 Apr (Shift 1)]
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A thin prism with angle 5° of refractive index 1.72 is combined with another prism of refractive index 1.9 to produce dispersion without deviation. The angle of second prism is____.
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Given a convex lens of refractive index \({\mu }_{2}\) in a liquid of refractive index \({\mu }_{1},{\mu }_{1}<{\mu }_{2}\) having radii of curvature \({\mathrm{R}}_{1},{\mathrm{R}}_{2}\mathrm{and}{\mathrm{R}}_{2}\) surface is silver polished. Where should an object be placed on the optical axis so that the real and inverted image is formed at the same place.
(Shift - I Memory Based)
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A concave-convex lens of refractive index \(1.5\) and the radii of curvature of its surfaces are \(30\) cm and \(20\) cm , respectively. The concave surface is upwards and is filled with a liquid of refractive index \(1.3\). The focal length of the liquid-glass combination will be:
[JEE Main 2025, 8 Apr (Shift 1)]
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A thin prism \({P}_{1}\) with angle 4° made of glass having refractive index 1.54 , is combine with another thin prism \({P}_{2}\) made of glass having refractive index 1.72 to get dispersion without deviation. The angle of the prism \({P}_{2}\) in degrees is
(Shift - I Memory based)
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Given is a thin convex lens of glass (refractive index \(\mu\)) and each side having radius of curvature \(R\). One side is polished for complete reflection. At what distance from the lens, an object be placed on the optic axis so that the image gets formed on the object itself?
[JEE Main 2025, 22 Jan (Shift 1)]
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For a transparent prism, if the angle of minimum deviation is equal to its refracting angle, the refractive index n of the prism satisfies.
[JEE Main 2026, 28 Jan (Shift 2)]
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The optical power of a lens is increased from \(0.1\text{ }\text{D}\) to \(2.5\text{ }\text{D}\). What is the relative shift in the focal length of the lens?
(Shift I Memory Based)
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A thin convex lens of focal length 5 cm and a thin concave lens of focal length 4 cm are combined together (without any gap) and this combination has magnification m1 when an object is placed 10 cm before the convex lens. Keeping the positions of convex lens and object undisturbed, a gap of 1 cm is introduced between the lenses by moving the concave lens away, which lead to a change in magnification of total lens system to m2. The value of \(\left|\frac{{m}_{1}}{{m}_{2}}\right|\) is ____.
[JEE Main 2026, 22 Jan (Shift 1)]
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The optical power of a lens is increased from \(0.1\text{ }\text{D}\) to \(2.5\text{ }\text{D}\). What is the relative shift in the focal length of the lens?
(Shift I Memory Based)
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A spherical surface of radius of curvature \(R\), separates air from glass (refractive index \(=1.5\) ). The centre of curvature is in the glass medium. A point object ' O ' placed in air on the optic axis of the surface, so that its real image is formed at ' I ' inside glass. The line OI intersects the spherical surface at P and \(\mathrm{PO}=\mathrm{PI}\). The distance PO equals to
[JEE Main 2025, 23 Jan (Shift 1)]
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Two thin convex lenses of focal lengths 30 cm and 10 cm are placed coaxially, 10 cm apart. The power of this combination is :
[JEE Main 2025, 7 Apr (Shift 1)]
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For a transparent prism, if the angle of minimum deviation is equal to its refracting angle, the refractive index n of the prism satisfies.
[JEE Main 2026, 28 Jan (Shift 2)]
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A thin prism \(P_1\) with an angle \(6^{\circ}\) and made of glass of refractive index 1.54 is combined with another prism \(P_2\) made from glass of refractive index 1.72 to produce dispersion without average deviation. The angle of prism \(P_2\) is:
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Car B overtakes another car A at a relative speed of \(40m{s}^{-1}\). How fast will the image of car B appear to move in the mirror of focal length 10 cm fitted in car A, when the car B is 1.9 m away from the car A ?
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When a beam of white light is allowed to pass through convex lens parallel to principal axis, the different colours of light converge at different point on the principle axis after refraction. This is called:
[JEE Main 2023, 24 Jan (Shift 2)]
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A monochromatic light wave with wavelength \(\lambda_1\) and frequency \({\nu }_{1}\) in air enters another medium. If the angle of incidence and angle of refraction at the interface are \(45^{\circ}\) and \(30^{\circ}\) respectively, then the wavelength \(\lambda_2\) and frequency \({\nu }_{2}\) of the refracted wave are:
[JEE Main 2023, 6 Apr (Shift 1)]
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The light rays from an object have been reflected towards an observer from a standard flat mirror, the image observed by the observer are:
A. Real
B. Erect
C. Smaller in size then object
D. Laterally inverted
Choose the most appropriate answer from the options given below:
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The critical angle for a denser-rarer interface is \(45^{\circ}\). The speed of light in rarer medium is \(3 \times 10^8 \mathrm{~m} / \mathrm{s}\). The speed of light in the denser medium is:
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Car B overtakes another car A at a relative speed of \(40{\mathrm{ms}}^{-1}\). How fast will the image of car B appear to move in the mirror of focal length 10 cm fitted in car A, when the car B is 1.9 m away from the car A?
[JEE Main 2021, 26 Aug (Shift 1)]
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Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her non-uniform and distorted. The doctor diagnosed the problems as:
[JEE Main 2021, 18 Mar (Shift 1)]
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Car B overtakes another car A at a relative speed of \(40m{s}^{-1}\). How fast will the image of car B appear to move in the mirror of focal length 10 cm fitted in car A, when the car B is 1.9 m away from the car A ?
[JEE Main 2021, 26 Aug (Shift 1)]
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Green light of wavelength \(5460\overset{\mathrm{o}}{\mathrm{A}}\) is incident on an air-glass interface. If the refractive index of glass is \(1.5\), the wavelength of light in glass would be \(\left(\mathrm{c}=3 \times 10^8 \mathrm{~ms}^{-1}\right)\)
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The thickness at the centre of a plano- convex lens is \(3 \mathrm{~mm}\) and the diameter is \(6 \mathrm{~cm}\). If the speed of light in the material of the lens is \(2 \times 10^8 \mathrm{~ms}^{-1}\). The focal length of the lens is:
[JEE Main 2021, 17 Mar (Shift 1)]
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A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index \(\frac{5}{3}\) is poured inside the bucket, then microscope has to be raised by \(30 \mathrm{~cm}\) to focus the object again. The height of the liquid in the bucket is:
[JEE Main 2023, 31 Jan (Shift 2)]
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.
Reason (R): The wavelengths of waves are different in different media.
In the light of the above statements, choose the most appropriate answer from the options given below.
[JEE Main 2023, 6 Apr (Shift 2)]
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An object is placed beyond the centre of curvature \(C\) of the given concave mirror. If the distance of the object is \(d_1\) from \(C\) and the distance of the image formed is \(d_2\) from \(C\), the radius of curvature of this mirror is:
[JEE Main 2021, 27 Aug (Shift 2)]
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A prism of refractive index \(\mu\) and angle of prism \(A\) is placed in the position of minimum angle of deviation. If minimum angle of deviation is also \(A\), then in terms of refractive index value of \(A\) is:
[JEE Main 2021, 25 Jul (Shift 2)]
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The light rays from an object have been reflected towards an observer from a standard flat mirror, the image observed by the observer are:
A. Real
B. Erect
C. Smaller in size than object
D. Laterally inverted
Choose the most appropriate answer from the options given below:
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A person has been using spectacles of power -1.0 diopter for distant vision and a separate reading glass of power 2.0 diopters. What is the least distance of distinct vision for this person:
[JEE Main 2023, 30 Jan (Shift 1)]
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The critical angle for a denser-rarer interface is \(45^{\circ}\). The speed of light in rarer medium is \(3 \times 10^8 \mathrm{~m} / \mathrm{s}\). The speed of light in the denser medium is:
[JEE Main 2023, 11 Apr (Shift 1)]
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A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index \(\frac{5}{3}\) is poured inside the bucket, then microscope have to be raised by \(30\mathrm{cm}\) to focus the object again. The height of the liquid in the bucket is:
[JEE Main 2023, 31 Jan (Shift 2)]
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The refractive index of converging lens is 1.4 . What will be the focal length of this lens, if it is placed in a medium of same refractive index? Assume the radii of curvature of the faces of lens are \(R_1\) and \(R_2\) respectively.
[JEE Main 2021, 16 Mar (Shift 2)]
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The magnifying power of a telescope with tube length \( 60 \mathrm{~cm} \) is 5 . What is the focal length of its eye piece ?
[JEE Main 2020, 2 Sep (Shift 2)]
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An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is \(12 \mathrm{~cm}\). when viewed from the opposite side, the apparent distance of the bubble is observed as \(4 \mathrm{~cm}\). If the side of the ice cube is \(24 \mathrm{~cm}\), the refractive index of the ice cube is:
[JEE Main 2023, 12 Apr (Shift 1)]
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