Previous Years Questions of Physics of AHSEC class 12 : Unit 9- Ray Optics

1:-The critical angles for glass (μ_g =1.5), water ( μw=1.33) , diamond ( μ_D =2.42) are θg , θw and θD respectively. Arrange the angles in descending order. (2026)

2:– Mention the condition where Snell’s law of refraction cannot be satisfied. (2025)

3:- If the critical angle of water with respect to air is 48.75 and sin 48.75=0.75, cos 48.75 =0.65 and tan 48.75=1.14 approximately, what will be the refractive index of water ?(2024)

4:- A plane mirror lies on x-y plane. If the incident ray is on y-z plane then the reflected ray and the normal will lie on ————-(i) x-y and y-z plane  (i) y-z and z-x plane  (iii) z-x and x-y plane (Choose the correct option)    (2023)

5:- Mirage is an optical phenomenon related to ——-(i) scattering (ii) total internal reflection (iii) total internal refraction (Choose the correct option).  (2023)

6:- In a prism except the position of minimum deviation there are_______ values of angle of incidence producing same angle of deviation.(Fill in the blank).    (2022)

7:- Name the equipment which can transmit optical signal through it and are used as ‘light pipe’. (2020)

8:-The sparkle of a diamond can be explained by which phenomenon of light ? (2019)

9:- A pair of stars of actual separation one minute of arc is observed with an astronomical telescope of magnifying power 100. What will be the separation of the image of the pair in degree?  (2018)

10:-An object is placed at the focus of a Convex lens. Where will the image be formed?(2017)

11:-State Snell’s law of refraction of light.(2014)

2-Mark Questions ( Section – SA-Short Answer)

1:- Double convex lenses are to be manufactured from a glass of refractive index 1.50 with both faces of the same radius of curvature. What is the radius of curvature if the focal length is to be 20 cm? (2026)

2:- Draw a neat ray diagram of formation of image by a refracting telescope. If f_e =1 cm, f_o = 100 cm, what is the magnification of the telescope?  1½+½=2    (2026)

3:- Show that in the case of spherical mirrors f= R/2. (2025)

4:- What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm. Is the system a converging or diverging lens?  1½+½=2. (2025)

5:- A magician makes a glass lens with n= 1.47 which disappears in a trough of liquid. What is the refractive index of the liquid ? Could the liquid be water? 1+1=2 (2024)

6:- A tank is filled with water to a height of 12.5 cm. The apparent depth of needle lying at the bottom of the tank is measured by. a microscope to be 9.4 cm. What is the refractive index of water ? (2023)

7:- Draw a ray diagram to make someone understand how a virtual and many times magnified image of an object is formed in a compound microscope. (2023)

8:- Rays parallel to each other but not parallel to the principal axis of a concave mirror will meet after reflection at the______ . Draw a diagram in support of your answer. ½+1½=2.  (2022)

9:- Write two conditions for a ray to suffer total internal reflection. 1+1=2 (2022)

10:- A concave mirror of focal length 18cm produces 3 times magnified errect image of an object. Find the position of the object. 2.  (2020)

11:- In a combination of lenses in contact, the power of the first lens is +2.5D and the focal length of the second lens is -25cm. Calculate the power or focal length of the lens combination. 2 (2020)

11:- Draw a neat diagram to show lateral shift of a ray refracted through a parallel-sided slab. Indicate the lateral shift in the diagram by a double-headed arrow.     1½+½=2 (2019)

12:- Establish the relation between the focal length (f) and radius of curvature (R) for a spherical mirror. 2 (2019)

13:- Draw the schematic diagram of a Cassegrain telescope.  2 (2018)

14:- Draw the ray diagram to show the location of the principal focus of a Convex mirror. Identify the pole and Centre of Curvature.  2 (2017)

15:- A square loop of side 3cm is placed 25cm away from a Concave mirror of focal length 10cm. The axis of the mirror passes through the intersecting point of the diagonals of the loop and is perpendicular to the plane of the loop. What is the. area enclosed by the image of the loop?  2 (2017)

16:- A man stands on vertical tower of height 20m. Calculate the distance upto which he will be able to see the surface of the earth. Given radius of earth is 6.4×10³ km.    2 (2016)

17:- Draw a ray diagram to show the formation of final image at least distance of distinct vision by a compound microscope.  2. (2015)

18:- Two lenses of powers +5D and -3D are in contact. Find the focal length of the combination. 2.  (2014)

3-Mark Questions ( Section – LA :- Long Answer)

1:-Draw a ray diagram showing the formation of a real image of an object by a concave mirror and establish the mirror equation. 1+2=3 (2026)

2:- Draw a ray diagram showing the passage of light ray through a triangular prism. What angle deviation? Find an expression for the angle of deviation in terms of angle of incidence i, angle of emergence e and prism angle A.  1+½+1½=3 (2026)

3:- A ray of light is suffering refraction at a spherical surface of radius of curvature R and separating two media of refractive indices n₁ (lighter) and n₂ (denser). Show that ,    3.  (2025)

4:- Find the position of the image formed by the lens combination given below. 1½+1½=3.         .    (2025)

5:- A convex lens of focal length fin an instrument is producing a virtual and magnified image at the near point (D). If the object distance is u show that its magnification is .  Name the instrument. 2½+½=3.  (2024)

Or ,    In the above question if the lens produces a virtual and many times magnified image at infinity show that its magnification is  . Where is the object situated ?  2½+½=3. (2024)

6:- Write the mirror equation. Define magnification and find the expression for magnification m from the mirror equation.   1+1+1=3   (2023)

7:– A beam of light converges at a point P. If a lens is placed in the path of convergent beam at a distance of 12 cm from P, at what point does the beam converge if the lens is a convex lens of focal length 20cm? Draw a neat diagram of it. 2+1=3. (2022)

8:- In a prism r₁ +r₂ = A and δ = i + e -A. When the prism is at the position of minimum deviation Dm, show that, refractive index of the material of the prism is . Also derive the expression for D_m for small angled prism. 2+1=3. (2020)

9:- Draw a ray diagram of a compound microscope forming an inverted and magnified image of an object. Which lens in the compound microscope acts as a simple microscope? If f_o = 1cm, f_e = 2cm and L=20 cm respectively, calculate the total magnification of the microscope. 1½+½+1=3   (2020)

10:- Deduce the equivalent focal length of two convex lenses of focal lengths F₁ and F₂ when placed in contact.  3. (2018)

11:- A Convex lens and a Concave lens of focal length 0.1m each are placed co-axially 0.03m. apart. Find the position of the image of an object placed 0.15m in front of the Convex lens.      3 (2017)

12:- You are given a prism in which the two refracting surfaces are at 90° with each other. Draw ray diagrams using this prism so that (i) the image of an object is rotated by 90° and (ii) the image of the object is rotated by 180°  .   3 (2017)

13:- Draw the ray diagram for the formation of image by a compound microscope. What is its magnification ?2+1=3. (2016)

14:- Establish the lens maker’s formula for a biconvex lens.3.  (2016)

15:- Two identical equiconvex lenses of refractive index 3/2 and focal length 16cm are kept in contact. The space between the lenses is filled with water of refractive index 4/3 . What is the focal length of the combination ? 3. (2016)

16:- Derive the expression for the equivalent focal length of a combination of two thin convex lenses in contact.  3 (2015)

17:- Deduce the relation for a convex lens producing virtual image.    3. (2015)

18:- An image is placed 30cm away from a concave lens of focal length 15cm. Find the position, size and nature of the image.  3 (2014)

19:- Deduce the relation  for a concave lens producing virtual image.    3. (2014)

20:- Find the value of angle of minimum deviation of a prism. [Given μ  = √2, A= 60°].     3 (2014)

5:- For refraction at a convex spherical surface of radius of curvature R from a medium of refractive index n₁ to a medium of refractive index n₂ (n₂>n₁), establish the relation-                   What will be the behaviour of a convex lens of refractive index 1.47 when it is immersed in a liquid of refractive index 1.47 ?   4+1=5 (2019)

6:- What are the main considerations in the construction of an astronomical telescope and how are they achieved? Why are mirror objectives rather than lens objectives used in modern telescope? Clarify giving schematic diagram how the problem of partial obstruction of ray of light by the eyepiece and observer is overcome in the improved version of reflection telescope.  2+1+2=5  (2017)

7:- The focal lengths of objective and eyepiece of a telescope are 200 cm and 10 cm respectively. It is used to get an image of the Sun on a screen placed 40cm behind the eyepiece. The diameter of the image is 6cm. What is the diameter of the Sun? Given, the distance from earth to the Sun is 1.5×10¹¹ m. 5 (2017)

8:- Establish the following relation-  5 (2014)