Interference and Diffraction Objective Question and Answer
Interference and Diffraction MCQ Multiple Choice Questions - Page 2 for Practice
31. If you look perpendicular at thin film and move yourself away from the film (staying perpendicular to the film), you will notice
Correct Answer is: Reflected light alternates between darker and brighter
32. In a longitudinal wave
Correct Answer is: The particles move parallel to the direction of the wave motion.
33. In a Youngs double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in the distance they travel by a multiple of
Correct Answer is: a wavelength
34. In case of thin film of non-uniform thickness, when illuminated with white light, the film appears colored. This is due to change of what factor?
Correct Answer is: All of above
35. In diffraction Fraunhofer diffraction pattern due to single slit central maxima is formed at center because
Correct Answer is: Light rays focused at the centre of the screen undergo constructive interference
36. In diffraction pattern of monochromatic light the bright bands formed are
Correct Answer is: of uniform intensity
37. In Fraunhofer diffraction pattern for single slit, a central maximum is obtained when angle of diffraction q is equal to zero. What it actually indicates?
Correct Answer is: All the diffracted rays are parallel and focused by slit at a single point on screen
38. In Fraunhofer diffraction wave front used is
Correct Answer is: Plane
39. In Fraunhofer diffraction, the incident wave front should be
Correct Answer is: Plane
40. In Fresnel diffraction
Correct Answer is: source of light is kept at finite distance from the aperture
41. In interference experiment, by keeping all other parameters constant, if you see the thin film interference from different angles, you will observe
Correct Answer is: Few colored bands and then general illumination
42. In interference experiment, monochromatic light is replaced by white light, we will see
Correct Answer is: Few colored bands and then general illumination
43. In Michelson interferometer semi silvered mirror is used to obtain
Correct Answer is: Phase coherence
44. In Michelson s interferometer 100 fringes cross the field view when the movable mirror is displaced through 0.0248 mm. Calculate the wavelength of monochromatic light used
Correct Answer is: 5890 Ao
45. In Newtons ring experiment, the diameter of the 15 th ring was found to be 0.590 and that of the 5th ring was 0.336 cm. If the radius of Plano convex lens is 100 cm, compute the wavelength of light used
Correct Answer is: 5880 Ao
46. In Newtons Ring experiments, the diameter of bright rings is proportional to
Correct Answer is: Square root of Odd Natural numbers
47. In Newtons Ring experiments, the diameter of dark rings is proportional to
Correct Answer is: Square root of natural number
48. In Newtons rings experiment, if monochromatic source of light is replaced by another monochromatic source of higher wavelength. What will be the effect on radius (or diameter)?
Correct Answer is: Radius (or diameter) will increase
49. In Newtons rings experiment, if we reduce the radius of curvature of Plano convex lens to zero, what will be effect on Newtons rings?
Correct Answer is: They will disappear
50. In Newtons rings experiment, if we reduce the radius of curvature of PlanoConvex lens to zero, what will be effect on Newtons rings?
Correct Answer is: They will disappear
51. In Newtons rings the central spot is
Correct Answer is: can be bright or dark
52. In plane transmission grating, the angle of diffraction for second order maxima for wavelength 5 x 10-5 cm is 30 degree. Calculate the number of lines in one centimeter of the grating surface
Correct Answer is: 5000 lines/cm
53. In reference with antireflection coating which of the following statement is true?
Correct Answer is: Thickness of the film should be increased for light of same wavelength but higher intensity
54. In reflected light the central fringes of Newtons ring is
Correct Answer is: dark
55. In thin film of wedge shaped, by keeping all other parameters constant, if only wavelength of incident light is increased. What will be the effect on bandwidth?
Correct Answer is: Bandwidth increases
56. In wedge shaped film the interference pattern has nature
Correct Answer is: Parallel to contact edge
57. Interference in thin film is mainly because of
Correct Answer is: Division amplitude
58. Interference in thin film is mainly because of
Correct Answer is: Division amplitude
59. Interference of light is evidence that
Correct Answer is: Light is a wave phenomenon
60. Interference pattern is observed in wedge-shaped film and bandwidth is noted. Now the angle of wedge is reduced to zero. What will be the effect on Bandwidth?
