Wave Optics Mock Test – Class 12 Physics

1. For a double-slit experiment with , , and , the distance of the first dark fringe from the central bright fringe is

2. A record of overlapping waves is shown below.

The row that needs correction is

3. A graph description is given below.

The slope of the graph represents

4. A graph is described below.

The dark points occur at

5. A small circular opening and a large circular opening are used with the same light. If denotes the opening diameter, the statement that best expresses the ray-to-wave transition is

6. A transparent material has polarising angle . If the angle of incidence is not equal to , the reflected light is generally

7. A formula card for a monochromatic wave contains the relation between angular frequency and ordinary frequency. The suitable relation is

8. Two coherent beams have amplitudes and . Another pair has amplitudes and . Assuming the same phase stability, the first pair gives better dark-bright contrast mainly because

9. A data sheet gives the following pairs for a monochromatic light wave in one medium.

The row that does not fit the usual meaning of the quantity is

10. Plane-polarised light of intensity first passes through an analyser at to its vibration direction and then through a second analyser at to the original vibration direction. The final intensity is

11. A narrow opening produces a bright region with blurred edges instead of a perfectly sharp geometrical shadow. The best wave-optics explanation is that

12. In a single-slit diffraction pattern, the secondary maxima are much less intense than the central maximum mainly because

13. Bright fringes appear symmetrically on both sides of the central bright fringe because

14. A pair of ideal polarising sheets is arranged with their transmission axes parallel. A second trial is made with the axes perpendicular. The correct comparison of transmitted intensity after the second sheet is

15. A telescope objective diameter is doubled while the wavelength of light remains the same. The minimum resolvable angular separation becomes

16. A graph of fringe width versus screen distance is drawn for fixed and . The graph should be

17. Fraunhofer diffraction is most closely associated with a situation in which the source and screen are effectively at very large distances, or lenses are used so that the incident and diffracted waves are treated as

18. A graph of intensity versus screen position in a Young's double-slit experiment has the central bright fringe at . The nearest dark fringes should appear at

19. In single-slit diffraction, if the first minimum occurs at angle and the second minimum at angle , then for small angles

20. Consider the following statements about wavefronts.
Statement I: A wavefront is a same-phase surface.
Statement II: A ray is normal to the wavefront in an isotropic medium.
Statement III: A spherical wavefront becomes more curved as it travels far away from a point source.

21. Two monochromatic waves reach a point with phase difference . The closest phase classification is

22. Consider the following statements about fringe width in Young's double-slit experiment.
Statement I: The spacing between consecutive bright fringes is equal to the spacing between consecutive dark fringes.
Statement II: The distance between a bright fringe and its nearest dark fringe is .
Statement III: Increasing while keeping and fixed increases .

23. In Newton's rings in reflected light, the radius of the th dark ring is given by . If , , and , the radius of the fourth dark ring is

24. An analyser is used after a polariser mainly to

25. A point source emits light in a uniform medium. After time , the radius of the spherical wavefront is

26. Use the construction record below.

The equality of the wavelet radii occurs because

27. A screen receives two coherent waves of equal intensity . At a point where , the intensity is

28. Colours seen in a thin soap film are mainly produced because light waves reflected from the upper and lower surfaces of the film

29. A polariser is an optical device that

30. A light wave has path difference between two points. The corresponding phase difference is

31. At a point, two equal-amplitude coherent waves have phase difference . If increasing by one wavelength changes by , the interference condition there

32. A Young's double-slit setup is changed by increasing the screen distance while keeping and fixed. The immediate geometrical effect is that the small-angle description becomes

33. A point has path difference for two coherent waves of equal amplitude. The point is

34. A student applies directly to unpolarised light incident on the first polariser. The correction is that

35. The distance between two consecutive plane wavefronts of the same monochromatic light in a medium is . If the frequency is , the speed of light in that medium is

36. Consider the following statements about phase and path difference.
Statement I: A path difference of , where is an integer, gives a phase difference of .
Statement II: A path difference of gives an odd multiple of .
Statement III: The sign of can show which path is longer, but the interference condition depends on the relative phase.

37. A light beam of unpolarised intensity passes through an ideal polariser and then an analyser at to the polariser axis. The transmitted intensity after the analyser is

38. A Young's double-slit experiment uses , , and . The fringe width is

39. A student draws the electric field vibration of reflected light at Brewster angle along the reflected ray. The drawing is incorrect because

40. Two independent ordinary bulbs do not usually produce a stable interference pattern on a screen because

41. In a polariser-analyser experiment, the transmitted intensity is maximum . When the analyser is rotated by an angle , the intensity becomes . The value of may be

42. A double-slit experiment has , , and . The second dark fringe from the central bright fringe is located at

43. A single-slit diffraction pattern and a Young's double-slit pattern are produced with the same , the same screen distance , and with slit width equal to slit separation . The ratio of the single-slit central maximum width to the double-slit fringe width is

44. A source used for a clear double-slit pattern is changed from monochromatic light to a broad mixture of wavelengths. The pattern becomes less sharply defined away from the centre mainly because

45. A point in Young's double-slit experiment has path difference . For equal slit intensities, is

46. Polarisation of light means that the vibrations of the light wave are

47. A microscope is used first with air and then with an oil-immersion medium of higher refractive index, keeping the objective geometry suitable. The resolution improves mainly because

48. In a single-slit diffraction pattern, the first minimum is observed at a distance from the central point on a screen at distance . For small angles, the slit width is approximately

49. Unpolarised light of intensity passes through a polariser and then an analyser whose axis makes with the polariser axis. The final intensity is

50. In a Young's double-slit experiment, two setups use the same light. Setup P has and . Setup Q has and . The ratio of fringe widths is