Ray Optics · JEE Main previous year questions

2026 33 questions

1. Q302026 · 8 Apr 2026 · Shift 2

   A thin biconvex lens is prepared from the glass ($\mu =1.5$) both curved surfaces of which have equal radii of $20\mathrm{cm}$ 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 ____ $\mathrm{cm}$.

   1. A.$10$
   2. B.$12.5$
   3. C.$13$
   4. D.$13.5$
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   Answer: A

2. Q472026 · 8 Apr 2026 · Shift 2· Numerical answer

   Some distant star is to be observed by some telescope of diameter of objective lens $a$, at an angular resolution of $3.0\times 10^{-7}\mathrm{radian}$. If the wavelength of light from the star reaching the telescope is $500\mathrm{nm}$, the minimum diameter of the objective lens of the telescope is ____ $\mathrm{cm}$. (nearest interger)

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   Answer: 203

3. Q412026 · 6 Apr 2026 · Shift 1
   
   1. A.1.66
   2. B.2.33
   3. C.2.66
   4. D.1.33
   Show answer

   Answer: A

4. Q422026 · 6 Apr 2026 · Shift 2

   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 ________.

   1. A.$1.5$
   2. B.$\sqrt{3}$
   3. C.$\sqrt{2}$
   4. D.$1.65$
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   Answer: C

5. Q502026 · 6 Apr 2026 · Shift 2· Numerical answer

   A concave mirror of focal length $10\text{ cm}$ forms an image which is double the size of object when the object is placed at two different positions. The distance between the two positions of the object is ________ $\text{cm}$.

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   Answer: 10

6. Q402026 · 5 Apr 2026 · Shift 1

   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.

   1. A.45
   2. B.30
   3. C.28
   4. D.58
   Show answer

   Answer: B

7. Q422026 · 5 Apr 2026 · Shift 1

   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

   1. A.increased two times
   2. B.increased $\frac{3}{2}$ times
   3. C.decreased two times
   4. D.decreased $\frac{3}{2}$ times
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   Answer: A

8. Q402026 · 5 Apr 2026 · Shift 2

   A thin convex lens and a thin concave lens are kept in contact and are co-axial. Which of the following statements is correct for this combination of two lenses ?

   1. A.behaves as concave lens if $|f_{\mathrm{convex}}|>|f_{\mathrm{concave}}|$
   2. B.behaves as concave lens if $|f_{\mathrm{convex}}|<|f_{\mathrm{concave}}|$
   3. C.behaves as convex lens if $|f_{\mathrm{convex}}|>|f_{\mathrm{concave}}|$
   4. D.Focal length of the lens system will change if the positions of two lenses are interchanged
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   Answer: A

9. Q412026 · 5 Apr 2026 · Shift 2

   An object $AB$ is placed $15\mathrm{cm}$ on the left of a convex lens $P$ of focal length $10\mathrm{cm}$. Another convex lens $Q$ is now placed $15\mathrm{cm}$ right of lens $P$. If the focal length of lens $Q$ is $15\mathrm{cm}$, the final image is ____.

   1. A.virtual, formed at $7.5\mathrm{cm}$ right of lens $Q$, with a size bigger than that of $AB$
   2. B.real, formed at $7.5\mathrm{cm}$ right of lens $Q$, with a size same as that of $AB$
   3. C.formed at infinity.
   4. D.real, formed at $7\mathrm{cm}$ right of lens $Q$, with a size smaller than that of $AB$
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   Answer: B

10. Q392026 · 4 Apr 2026 · Shift 1
    
    1. A.2.5
    2. B.5
    3. C.7.5
    4. D.7
    Show answer

    Answer: B

11. Q442026 · 4 Apr 2026 · Shift 1

    A telescope with objective diameter $R$ is used to observe a distant star emitting light of wavelength $500\text{ nm}$, at a resolution of $5\times 10^{-7}\text{ radian}$. The value of $R$ is ________ $\text{cm}$.

    1. A.61
    2. B.122
    3. C.244
    4. D.305
    Show answer

    Answer: B

12. Q412026 · 4 Apr 2026 · Shift 2

    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 ____.

    1. A.0.5
    2. B.2.5
    3. C.0.8
    4. D.1.25
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    Answer: D

13. Q402026 · 2 Apr 2026 · Shift 1

    For a thin symmetric prism made of glass (refractive index $1.5$), the ratio of incident angle and minimum deviation will be ____

    1. A.$3:4$
    2. B.$3:2$
    3. C.$2:1$
    4. D.$1:2$
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    Answer: B

14. Q412026 · 2 Apr 2026 · Shift 1
    
    1. A.1
    2. B.0.5
    3. C.1.2
    4. D.0.25
    Show answer

    Answer: A

15. Q412026 · 2 Apr 2026 · Shift 2
    
    1. A.$3\sqrt{3}/1.6$
    2. B.$\sqrt{3}$
    3. C.$3.2/\sqrt{3}$
    4. D.$4\sqrt{3}/5$
    Show answer

    Answer: D

16. Q492026 · 2 Apr 2026 · Shift 2· Numerical answer

    If sunlight is focused on a paper using convex lens, it starts burning the paper in shortest time when the lens is kept at $30\mathrm{cm}$ above the paper. If the radius of curvature of the lens is $60\mathrm{cm}$ then the refractive index of the lens material is $\frac{\alpha }{10}$. The value of $\alpha$ is ____.

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    Answer: 20

17. Q362026 · 28 Jan 2026 · Shift 1

    The magnitudes of power of a biconvex lens (refractive index $1.5$) and that of a plano-concave lens (refractive $\text{index}=1.7$ ) are same. If the curvature of planoconcave lens exactly matches with the curvature of back surface of the biconvex lens, then ratio of radius of curvature of front and back surface of the biconvex lens is ____

    1. A.$2:5$
    2. B.$5:2$
    3. C.$12:5$
    4. D.$5:12$
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    Answer: B

18. Q422026 · 28 Jan 2026 · Shift 1

    Given below are two statements : Statement I : A plane wave after passing through prism remains as plane wave but passing through small pin hole may become spherical wave. Statement II : The curvature of a spherical wave emerging from a slit will increase for increasing slit width. In the light of the above statements, choose the correct answer from the options given below :

    1. A.Both Statement I and Statement II are false
    2. B.Both Statement I and Statement II are true
    3. C.Statement I is true but Statement II is false
    4. D.Statement I is false but Statement II is true
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    Answer: C

19. Q492026 · 28 Jan 2026 · Shift 1· Numerical answer

    A convex lens of refractive index $1.5$ and focal length $f=18\mathrm{cm}$ is immersed in water. The difference in focal lengths of the given lens when it is in water and in air is $\alpha \times f$. The value of $\alpha$ is ____ . (refractive index of water $=4/3$ )

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    Answer: 3

20. Q382026 · 28 Jan 2026 · Shift 2
    
    1. A.$-2$
    2. B.$-2.5$
    3. C.$+2.5$
    4. D.$+2$
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    Answer: A

21. Q412026 · 28 Jan 2026 · Shift 2

    For a transparent prism, if the angle of minimum deviation is equal to its refracting angle, the refractive index $n$ of the prism satisfies.

    1. A.$n\ge 2$
    2. B.$\sqrt{2}<n<2$
    3. C.$1<n<2$
    4. D.$\sqrt{2}<n<2\sqrt{2}$
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    Answer: B

22. Q282026 · 24 Jan 2026 · Shift 1

    The exit surface of a prism with refractive index $n$ is coated with a material having refractive index $\frac{n}{2}$. When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is ____ .

    1. A.$60^{\circ }$
    2. B.$30^{\circ }$
    3. C.$15^{\circ }$
    4. D.$45^{\circ }$
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    Answer: A

23. Q352026 · 24 Jan 2026 · Shift 1

    In a microscope of tube length $10\mathrm{cm}$ two convex lenses are arranged with focal length of $2\mathrm{cm}$ and $5\mathrm{cm}$ . Total magnification obtained with this system for normal adjustment is $(5{)}^k$. The value of $k$ is ____ .

    1. A.4
    2. B.5
    3. C.2
    4. D.3.5
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    Answer: C

24. Q402026 · 23 Jan 2026 · Shift 1

    A thin prism with angle $5^{\circ }$ 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 ____ .

    1. A.$5^{\circ }$
    2. B.$4^{\circ }$
    3. C.$4.5^{\circ }$
    4. D.$6^{\circ }$
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    Answer: B

25. Q442026 · 23 Jan 2026 · Shift 1

    Consider light travelling from a medium $A$ to medium $B$ separated by a plane interface. If the light undergoes total internal reflection during its travel from medium $A$ to $B$ and the speed of light in media $A$ and $B$ are $2.4\times 10^8\text{ m/s}$ and $2.7\times 10^8\text{ m/s}$, respectively, then the value of critical angle is :

    1. A.${\cos }^{-1}\left(\frac{8}{9}\right)$
    2. B.${\sin }^{-1}\left(\frac{8}{9}\right)$
    3. C.${\cot }^{-1}\left(\frac{3}{\sqrt{13}}\right)$
    4. D.${\tan }^{-1}\left(\frac{8}{\sqrt{17}}\right)$
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    Answer: D