Interference and Diffraction Multiple Choice Questions and Answers

111. A film is said to be thin if its thickness is

1. Much smaller than wavelength of light
2. Comparable with one wavelength of light
3. Of the order of nanometer (10^-9 m)
4. Of the order of Pico meter (10^-12 m)

112. A grating has 6000 lines per cm. How many orders of light of wavelength 4500 A^o can be seen?

1. 1
2. 2
3. 3
4. 4

113. A monochromatic (single frequency, single wavelength) light ray in air (n = 1) enters a glass prism (n = 1.5). In the glass prism

1. Both the frequency and the wavelength are the same as in air
2. The frequency is the same, but the wavelength is greater than in air
3. The frequency is the same, but the wavelength is smaller than in air
4. The wavelength is the same, but the frequency is greater than in air

114. A slit of width a is illuminated by white light. For what value of a will the first minimum for red light fall at an angle of 300 wavelength of red light is 6500 A^o

1. 1.1 x 10^-3cm
2. 1.4 X 10^-4cm
3. 1.3 X 10^-4cm
4. 1.6 X 10^-4 cm

115. A thin film is observed in white light. The color of the film seen at a particular point depends upon

1. Location of observer
2. Width of the source
3. Distance of the source
4. Brightness of the source

116. A wavelength is commonly measured in which one of the following units?

1. Radians
2. Angstroms
3. Electron volts
4. Seconds

117. A wedge shaped thin has

1. Non-uniform thickness
2. Zero thickness at one end and it increasing towards other end
3. Zero thickness at both ends
4. Thickness increase and decrease alternately

118. A wedge shaped thin has

1. Non-uniform thickness
2. Zero thickness at one end and it increasing towards other end
3. Zero thickness at both ends
4. Thickness increase and decrease alternately

119. An index of refraction less than one for a medium would imply

1. That the speed of light in the medium is the same as the speed of light in vacuum
2. That the speed of light in the medium is greater than the speed of light in vacuum
3. Refraction is not possible
4. Reflection is not possible

120. An index of refraction less than one for a medium would imply

1. That the speed of light in the medium is the same as the speed of light in vacuum
2. That the speed of light in the medium is greater than the speed of light in vacuum
3. Refraction is not possible
4. Reflection is not possible