Interference and Diffraction Multiple Choice Questions and Answers

121. Whose principle or law states that each point on a wave front may be considered a new wave source? Is it

1. Snells Law
2. Huygenss Principle
3. Youngs Law
4. Hertzs Law

122. Why in Newtons rings setup, the beam splitter (mirror) is kept at 450?

1. It allows light rays to incident at 450 over the top surface of Planoconvex lens
2. It allows light rays to incident uniformly over the top surface of Planoconvex lens
3. It allows light rays to incident parallel over the top surface of Planoconvex lens
4. It allows light rays to incident at 900 over the top surface of Planoconvex lens

123. Why in Newtons rings the center spot is always dark?

1. The thickness of the film is zero at center
2. The path difference between incident ray and reflected ray is 1/2 wavelength
3. The incident ray and reflected ray undergo destructive interference
4. All of above

124. X-ray diffraction can be observed by using

1. Diffraction Grating
2. Rock salt crystal
3. Convex lens
4. Michelsons interferometer