Interference

The principle of superposition states that:

• Light behaves only as a particle
  

• Total displacement is the algebraic sum of individual displacements
  

• Two light waves cannot pass through the same point
  

• The energy of a wave is always conserved

Interference of light occurs due to:

• Reflection of light
  

• Polarization of light

• Diffraction of light
  

• Superposition of coherent waves
  

Two light sources are said to be coherent if they have:

• Constant phase difference
  

• Same amplitude
  

• Different frequencies

• Same intensity
  

Fresnel's biprism is used to:

• Measure angle of diffraction
  

• Produce interference fringes from a single source
  

• Measure refractive index

• Split light into components
  

The fringe width in Fresnel’s biprism experiment is directly proportional to:

• Refractive index
  

• Distance between virtual sources
  

• Thickness of the prism

• Wavelength of light used
  

When light reflects from a denser medium, it undergoes a phase change of:

• No phase change

• 270°

• 180°
  

• 90°
  

Colors of thin films (like soap bubbles) are due to diffraction

• True

• False

The condition for constructive interference in a thin film (air film) is:

• μt=λ/4

• 2μt=(2n+1)λ/2

• 2μt=nλ

• 
  μt=nλ

In Newton’s rings, the rings are:

• Square
  

• Rectangular
  

• Concentric circles
  

• Irregular shapes

Michelson Interferometer is mainly used to:

• Focus laser beams

• Measure intensity of light
  

• Determine frequency of light
  

• Measure very small distances or wavelengths