Interference and Diffraction Multiple Choice Questions and Answers

71. Newtons rings experiment is performed and radius (or diameter) is calculated. Now Plano-convex lens is replaced with another Plano-convex lens of greater Radius of curvature. What will be effect on radius (or diameter)?

1. Radius (or diameter) will remain constant but there will be more brightness
2. Radius (or diameter) will increase
3. Radius (or diameter) will decrease
4. There will be no effect

72. Newtons rings experiment is performed with air gap between lens and plate. Now that gap is filled with water. What will be effect on radius (or diameter)?

1. Radius (or diameter) will remain constant but there will be more brightness
2. Radius (or diameter) will increase
3. Radius (or diameter) will decrease
4. There will be no effect

73. On a rainy day, small oil films on water show brilliant colors. This is due to

1. dispersion
2. interference
3. diffraction
4. Polarization

74. Optical fiber works on the

1. principle of refraction
2. total internal reflection
3. scattering
4. interference

75. Radio telescopes are better than optical telescopes because

1. they can detect faint galaxies which no optical telescope can
2. they can work even in cloudy conditions
3. they can work during the day and night
4. All of the above

76. Rainbow is due to

1. absorption of sunlight in minute water droplets
2. diffusion of sunlight through water droplets
3. ionization of water deposits
4. refraction and reflection of sunlight by water droplets

77. Second glass plate in Michelson s Interferometer is known as

1. Extra glass plate
2. Compensating glass plate
3. Simple Glass Plate
4. None of these

78. significant diffraction of X ray can be obtained

1. By a single slit
2. By a double slit
3. By diffraction
4. By Atomic crystal

79. The angle of incidence for a wave

1. can be measured between the incident ray and the normal
2. can be measured between the incident wave front and the boundary
3. is equal to the angle of reflection
4. all of the above

80. The characteristic that distinguishes a laser beam from an ordinary light beam is

1. The greater frequency of the laser beam
2. The coherence of the laser beam
3. The color of the laser beam
4. The greater polarization of the laser beam