Ray Optics and Optical Instruments Mock Test – Class 12 Physics

1. A student measures the angle between an incident ray and a plane mirror surface as . The reflected ray will make what angle with the normal?

2. For two thin lenses separated by a distance , the equivalent focal length is given by

3. A convex lens is used to project a sharp enlarged image of a slide on a screen. The slide should be placed

4. In a separated-lens calculation, all distances are first written in . The safest way to use is to

5. For light going from glass of refractive index to air, the value of is

6. A comparison of vision defects is shown below:

The acceptable rows are

7. A light ray is inside a liquid with refractive index and approaches the liquid-air surface. The critical angle satisfies

8. A concave lens of focal length is used with a real object in front of it. The image distance is

9. The absolute refractive index has no unit because it is

10. A student's slab diagram shows the emergent ray making a smaller angle with the normal than the incident ray, although the slab is in air on both sides. The main error is that the student has ignored

11. A concave spherical mirror is used with a narrow beam of rays parallel to its principal axis. After reflection, the rays meet near the

12. An object is placed in front of a convex spherical glass surface. Light travels from air into glass , and the radius of curvature of the surface is . The image distance is

13. During refraction at a glass-air boundary, the quantity that remains unchanged for a given light wave is

14. A virtual image formed by a convex mirror lies behind the mirror. If the incident light travels from left to right and the mirror pole is the origin, the image distance is

15. In a compound microscope, the objective lens should have

16. A prism has angle . At minimum deviation, the internal refraction angle at each face is

17. A comparison between dispersion and scattering is made:
I. Dispersion separates colours because refractive index depends on wavelength.
II. Rayleigh scattering redirects shorter wavelengths more strongly.
III. A prism spectrum and the blue sky have exactly the same mechanism.
IV. Rainbow formation includes dispersion, while blue sky mainly involves scattering.
The suitable set is

18. A learner mixes up microscope and telescope formulas. The expression belongs to

19. A result table for refraction at a spherical surface is shown:

The acceptable rows are

20. For a rectangular slab, the lateral displacement is . If and remain fixed while the slab thickness is doubled, the lateral displacement becomes

21. The power of a lens is defined as

22. An object is kept between two plane mirrors inclined at . If the object is on the angle bisector, the number of images is

23. A telescope is mainly used to view

24. An equiconvex lens in air has refractive index , with . Its focal length is

25. Ray optics mainly describes light by treating it as travelling along what kind of path in a uniform medium?

26. In a concave-lens ray diagram, the refracted rays from the top of a real object are diverging. The image point is located by

27. For air to glass refraction at a convex spherical surface, , , and . The object distance for which the image is formed at infinity is

28. In a desert mirage, the lower air layer near the hot ground has

29. A thin prism of angle has , , and . Its angular dispersion and dispersive power are respectively

30. A final comparison of optical instruments is shown below:

The acceptable rows are

31. The eyepiece of a compound microscope mainly acts as

32. A thin lens is described as having negligible thickness compared with its focal length and object distance. This approximation is useful because

33. A prism spectrum and a rainbow both show colour separation. The shared physical cause is

34. A simple microscope has focal length . Taking , its magnifying power for final image at the near point is

35. A microscope and a telescope are both included in ray optics because their working can be started by studying

36. For the convex-lens case , , and , the magnification is

37. A thin-lens combination has equivalent focal length , and a real object is placed in front of it. The image distance and magnification are

38. The image formed by a simple microscope for normal magnifying use is

39. A formula record for two-lens systems is shown below:

The acceptable rows are

40. The same simple microscope has . For relaxed-eye viewing, its magnifying power is

41. A telescope objective of larger aperture is preferred mainly because it

42. A graph is drawn for two fixed convex lenses separated by distance , with on the vertical axis and on the horizontal axis. According to , the graph is

43. At minimum deviation for a prism, the following quantities are recorded:

The correct pair of angles to use in is

44. A transparent slab of thickness and refractive index produces apparent shift . If is increased while is unchanged, the apparent shift

45. A biconvex lens has focal length in air. When immersed in a liquid, its focal length becomes . If the lens material has refractive index , the refractive index of the liquid is

46. A ray travels inside glass and strikes the glass-air boundary at an angle greater than the critical angle. The result is that

47. A convex mirror is preferred as a rear-view mirror in vehicles mainly because it

48. A concave lens receives parallel rays from the left. The refracted rays diverge and appear to come from a focus on the left side of the lens. Under the usual sign convention, the focal length is

49. A comparison between a compound microscope and an astronomical telescope is shown below:

The acceptable rows are

50. A ray is directed through the principal focus of a concave mirror before striking the mirror. After reflection, the ray becomes