Title 09. RAY OPTICS AND OPTICAL INSTRUMENTS.pdf ✅

09. RAY OPTICS AND OPTICAL INSTRUMENTS NEET PREPARATION (MEDIUM PHYSICS PAPER) Date: March 12, 2025 Dura on: 1:00:00 Total Marks: 180 INSTRUCTIONS INSTRUCTIONS PHYSICS 1. A ray of light is incident on a right angle prism of refractive index as shown in the figure. The ray of light is reflected and refracted at the surface of the prism. The angle between the reflected and refracted rays at the surface is : (1) 120° (2) 90° (3) 45° (4) 150° 2. Two lenses of power and are combined to form a compound lens. Its focal length in will be - (1) (2) (3) (4) 3. Assertion : A concave mirror and convex lens both have the same focal length in air. When they are sub‐ merged in water, they will have same focal length. Reason : The refractive index of water is smaller than the refractive index of air. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Both Assertion and Reason are incorrect. 4. A fish in water (refractive index ) looks at a bird vertically above in the air. If is the height of the bird and is the depth of the fish from the surface, then the distance of the bird as estimated by the fish is (1) (2) (3) (4) 5. A layer of ice lies on a glass plate . A ray of light makes an angle of inci‐ dence on the surface of ice as shown in the figure below. Match column I with column II Column I Column II A P B Q C . Refractive index of ice with respect to glass R (1) A - P, B - Q, C - R (2) A - Q, B - P, C - R (3) A - Q, B - R, C - P (4) A - Q, B - R, C - P √3 AC +2.50 D −3.75 D cm 40 −40 −80 160 n y x x + y (1 + ) 1 n y + x (1 − ) 1 n x + y (1 − ) 1 n x + ny (μ = 1.33) (μ = 1.5) 60 ∘ sin r1 (1/√3) sin r2 (3/√3) /8 8/9
6. The refractive index of water, glass and diamond are 1.33, 1.50, 2.40 respectively. The refractive index of diamond relative to water and refractive index of glass relative to diamond, respectively are nearly (1) 0.554, 0.625 (2) 1.80,0.625 (3) 0.554, 1.6 (4) 1.80, 1.6 7. A man can see the objects between and He uses the lens to see the far objects. Then due to the lens used, the near point will be at (1) (2) (3) (4) 8. A certain far-sighted person cannot see object closer to the eye than . The power of the lens which will enable him to read at a distance of will be (1) (2) (3) (4) 9. The angle of minimum deviation measured with a prism is and the angle of prism is . The refractive index of prism material is- (1) (2) 2 (3) (4) 10. Angle of minimum deviation for a prism of re‐ fractive index 1.5 is equal to the angle of prism. Then the angle of prism is (1) (2) (3) (4) 11. A convex lens is made up of three different ma‐ terial as shown in the figure, for a point object placed on its axis the number of image are: (1) 1 (2) 5 (3) 4 (4) 3 12. A ray of light falls on a transparent sphere with centre at as shown in figure. The ray emerges from the sphere parallel to line . The refrac‐ tive index of the sphere is (1) (2) (3) (4) 13. The velocity of light in a medium is half its ve‐ locity in air. If ray of light emerges from such a medium into air, the angle of incidence, at which it will be totally internally reflected, is (1) (2) (3) (4) 14. Assertion : Just before setting the sun may. appear to be oval (ellipse like).This happens due to refraction. Reason : Due to refraction of light, ray through the atmos‐ phere causes different magnification. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 15. The final image formed by an astronomical telescope is (1) real, erect and diminished (2) virtual, inverted and diminished (3) real, inverted and magnified (4) virtual, inverted and magnified 16. Calculate the focal length of a reading glass of a person if his distance of distinct vision is . (1) (2) (3) (4) 17. The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is . The focal length of lenses are (1) (2) (3) (4) 18. An object is kept at a distance of from a thin lens and the image formed is real. If the ob‐ ject is kept at a distance of from the same lens, the image formed is virtual. If the sizes of the image formed are equal the focal length of the lens will be (1) (2) (3) (4) 15 cm 30 cm 30 cm cm 10 3 cm 100 3 15 cm 100 cm 25 cm 3 D 1 D 5 D 2 D 30 ∘ 60 ∘ √2 3 2 4 3 (sin 48 036 ′ = 0.75) 80 ∘ 41 ∘24 ′ 82 ∘48 ′ A = 60 ∘ C AB 3/2 1/2 √2 √3 30 ∘ 15 ∘ 60 ∘ 45 ∘ 75 cm 37.5 cm 100.4 cm 25.6 cm 75.2 cm 20 cm 11 cm, 9 cm 15 cm, 5 cm 10 cm, 10 cm 18 cm, 2 cm 16 cm 6 cm 11 cm 21 cm 17 cm 15 cm
19. The curve of angle of incidence versus angle of deviation shown has been plotted for prism. The value of refractive index of the prism used is : (1) (2) (3) (4) 20. Considering normal incidence of ray, the equiv‐ alent refractive index of combination of two slabs shown in figure is (1) 1.43 (2) 1.8 (3) 2.5 (4) 1.8 21. Radii of curvature of a converging lens are in the ratio 1: 2. Its focal length is and refrac‐ tive index is 1.5. Then its radii of curvature are ________respectively. (1) (2) (3) (4) 22. If represents refractive index medium w.r.to medium . Then the product is equal to (1) (2) (3) (4) 23. A ray of light is incident at on one face of a prism of angle and the emergent ray makes with the incident ray. The refractive index of the prism is: (1) 1.732 (2) 1.414 (3) 1.5 (4) 1.33 24. When a lens of refractive index is placed in a liquid of refractive index , the lens looks to be disappeared only if (1) (2) (3) (4) 25. A coin is present on the bottom of a water tank of depth If the refractive index of the wa‐ ter is 1.5 then shift in the position of the coin as seen by an observer standing in air is (1) (2) (3) (4) 26. For a point object, which of the following al‐ ways produces virtual image in air? (1) Convex mirror (2) Biconvex lens (3) Concave mirror (4) Plano-convex lens 27. A hollow prism is filled with water and placed in air. It will deviate the incident rays (1) Towards the base (2) Away from base (3) Parallel to base (4) Towards or away from base depending on the location 28. A short pulse of white light is incident from air to glass slab at normal incidence. After travelling through the slab, the first colour to emerge is :- (1) Green (2) Blue (3) Red (4) Violet 29. A ray of light passes from vacuum into a medium of refractive index , the angle of inci‐ dence is found to be twice the angle of refrac‐ tion. Then the angle of incidence is (1) (2) (3) (4) 30. Assertion : By increasing the diameter of the objective of telescope, we can increase image brightness. Reason : A telescope is used to provide angular magnifi‐ cation of distant objects. (1) Both Assertion and Reason are true and Reason is correct explanation of the Assertion. (2) Both Assertion and Reason are true but Reason is not the correct explanation of the Assertion. (3) Assertion is true but Reason is false. (4) Assertion is false but Reason is true. 31. An astronomical telescope with magnification 50 is to be designed in normal adjustment. Length of the tube is . The powers of ob‐ jective and eyepiece are respectively. (1) 2D, 50 D (2) 1.5D, 20 D (3) 1D, 40 D (4) 1D, 50 D 32. A beam of light from a source is incident nor‐ mally on a plane mirror fixed at a certain dis‐ √3 √3 √2 2 √3 √2 6 cm 9 cm and 18 cm 6 cm and 12 cm 3 cm and 6 cm 4.5 cm and 9 cm jμi i j 2μ1 × 3μ2 × 4μ3 3μ1 3μ2 1 1μ4 4μ2 60 ∘ 30 ∘ 30 ∘ n1 n2 n1 = n2/2 n1 = 3n2/2 n1 = n2 n1 = 5n2/2 30 cm. 10 cm 20 cm 5 cm 2 cm μ 2 cos−1( ) μ 2 sin −1 (μ) sin −1( ) μ 2 cos −1( ) μ 2 102 cm L