Q95 / 180 · AIIMS 2007 · Physics

Assertion : A white source of light during interference forms only white and black fringes. Reason : Width of fringe is inversely proportional to the wavelength of the light used.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • C
    If assertion is true but reason is false
  • Correct answer
    D
    If both assertion and reason are false.

Solution

Fringe width \(\beta=\frac{\lambda D}{d}\). This depends on the wavelength. Diffraction depends on the wavelength of light. Therefore if a white source of light is used, only the central fringe will be white. All the rest have different wavelengths and some orders will also overlap for different colours.

Hence, the correct answer is option: 'D'.

Relevant Questions