# Ray Optics and Optical Instruments MCQs Mock Test of Class 12th Physics

Welcome to your Ray Optics and Optical Instruments MCQs Mock Test of Class 12th Physics

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Q.1. If a glass prism is dipped in water, its dispersive power

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Q.2. The objective of a telescope must be of large diameter in order to

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Q.3. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is

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Q.4. To increase the angular magnification of a simple microscope, one should increase

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Q.5. Which of the following colour of white light deviated most when passes through a prism?

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Q.6. For a total internal reflection, which of the following is correct?

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Q.7. Mirage is a phenomenon due to

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Q.8. Critical angle of glass is θ2 and that of water is θ2. The critical angle for water and glass surface would be (μg = 3/2, μw = 4/3).

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Q.9. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then

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Q.10. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will

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Q.11. Which of the following forms a virtual and erect image for all positions of the object?

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Q.12. Two lenses of focal lengths 20 cm and – 40 cm are held in contact. The image of an object at infinity will be formed by the combination at

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Q.13. Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be

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Q.14. An under-water swimmer cannot see very clearly even in absolutely clear water because of

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Q.15. The field of view is maximum for

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Q.16. A person is six feet tall. How tall must a plane mirror be if he is able to see his entire length?

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Q.17. The image formed by a concave mirror is

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Q.18. When light is refracted into a medium,

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Q.19. Which of the following phenomena is used in optical fibres ?

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Q. 20. Critical angle of light passing from glass to water is minimum for

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Question 21. Which of-the following is not a property of light?

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Question 22. Two points P and q are situated at the same distance from a source of light but on opposite sides. The plane difference between the light waves passing through P and q will be:

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Question 23. The phase difference between the electric and the magnetic field vectors in electromagnetic waves is

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Question 24. A ray of light travelling in air is incident of a glass slab. The ray gets partly reflected and partly refracted. The phase difference between the reflected and the refracted waves is :

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Question 25. Which of the following cannot be polarised?

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Question 26. Light year is the unit of:

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Question 27. If a mirror is approaching you at a speed of 10 ms^1, the speed with which your image approach you is:

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Question 28. The refractive indices (R.I.) of glass and water with respect to air are 3/2 and 4/3 respectively. The R.I. of glass w.r. to w ater is:

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Question 29. The angle of minimum deviation for an equilateral glass prism is 30°. Refractive index of the prism is:

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Question 30. A beam of light is incident at 60° to a plane surface. The reflected and refracted rays are perpendicular to each other. What is the R.I. of the surface:

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Question 31. A concave mirror of focal length f produces an image n times the size of the object. If the image is real then the distance of the object is:

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Question 32. A convergent lens will become less convergent in :

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Question 33. A thin glass (RI = 32) lens has optical power of – 5D in air. Its optical power in a liquid medium with RI = 1.6 will be:

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Q 34. On reflection from a denser medium, a light wave suffers a phase difference of:

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Question 35. The branch of optics dealing with the formation of images using the concept of straight line propagation of light is called:

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Question 36. When light travels from one medium to another, which of the following does not change?

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Question 37. Two lens of power -15 D and +5 D are placed in contact co-axially. The focal length of equivalent lens is:

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Question 38. Refractive index of water and glass are 43 and 53. A light ray is going to water from glass. Then, its critical angle will be:

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Question 39. A blue cross on the white background is illuminated with white light and is observed through red filter. What is seen?

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Question 40. The angle of deviation for a prism is greatest for:

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Question 41. A double convex air bubble in water behaves as:

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Q 42.The air bubble inside water shine due to:

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Question 43. When a ray of light (white) enters a lens, undergoes a change is:

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Question 44. Radio waves from an antenna travel with the velocity of:

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Question 45. A point object is placed at the centre of a glass sphere of radius 6 cm 3 and RI = 32. The distance of virtual image from the surface of the sphere is :

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Question 46. The RI. of the material of a prism is √2 and its refracting angle is 30°. One of the refracting surface of the prism is made a mirror. A beam of monochromatic light entering the prism from the other face retraces its path, after reflection from mirror surface. The angle of incidence on prism is:

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Question 47. A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when seen in the light of mean λ = 5000 A is of the order of:

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Question 48. When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is :

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Question 49. A convex lens is dipped in a liquid, whose R.I. is equal to that of R.I. of material of the lens. Then its focal length will:

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The velocity of light in vacuum is 3 × 1010 cms-1. The velocity of light in a medium (µ = 1.5) is: