Interference and Diffraction Multiple Choice Questions and Answers

101. Two sources of light are said to be coherent if

1. they produce waves of the same wave length
2. they have the same amplitude of vibration
3. they produce waves in the medium simultaneously
4. they produce waves of the same amplitude

102. What is the effect of increasing the number of slits on the intensity of Central maxima of diffraction pattern of a diffraction grating?

1. Intensity of central maxima will decrease
2. Intensity of central maxima will increase
3. There will not be any effect
4. Diffraction pattern will disappear

103. What is the highest order spectrum which may be seen with monochromatic light of wavelength 5000 A^o by means of diffraction grating with 5000 lines/cm?

1. 2
2. 4
3. 8
4. 16

104. What is the name of the process whereby waves travel around corners and obstacles in their paths?

1. Reflection
2. Refraction
3. Interference
4. Diffraction

105. What is the nature of interference pattern at the contact edge of wedge shaped film

1. Always bright
2. Always dark
3. Bright or dark depending upon the thickness of other end
4. Bright or dark depending upon the wavelength of the light

106. What is the nature of interference pattern for thin film of wedge shaped

1. Concave outside
2. Convex outside
3. Equally spaced
4. Concave inside

107. What is the nature of interference pattern for thin film of wedge shaped

1. Concave outside
2. Convex outside
3. Equally spaced
4. Concave inside

108. What is the speed of light in glycerin (n = 1.47) expressed in terms of the speed of light in a vacuum?

1. 2.04c
2. 1.47c
3. 0.680c
4. 1.00c

109. What is true for intensity of scattered light according to Rayleighs law?

1. The intensity for scattering for light of largest wavelength more
2. The light of smallest wavelength will be scattered more
3. All the wavelengths are scattered equally
4. Intensity of light is not affected by scattering

110. When a light ray travelling in glass is incident on an air surface

1. it will refract away from the normal
2. some of the light may be reflected
3. all of the light may be reflected
4. all of A, B, and C