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

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

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

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

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

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

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

Q.7. Mirage is a phenomenon due to

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).

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

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

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

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

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

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

Q.15. The field of view is maximum for

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

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

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

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

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

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

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:

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

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 :

Question 25. Which of the following cannot be polarised?

Question 26. Light year is the unit of:

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

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:

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

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:

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:

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

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:

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

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

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

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

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:

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

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

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

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

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

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

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 :

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:

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:

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 :

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:

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