Answer: Coloured fringes with white central bright fringe.
- A Coloured fringes with white central bright fringe
- B No fringe pattern forms with white light present
- C Generally black and white alternating fringes with little colour
- D Mainly red-coloured fringes appear across the entire screen
Correct answer: A. Coloured fringes with white central bright fringe
Explanation: White light contains many wavelengths. Each wavelength has different fringe spacing. The central fringe (zero path difference) is white. Away from centre, colours separate and overlap to produce coloured fringes.
Two coherent slits S₁ and S₂ act as secondary sources; at each point on the screen, the path difference between light from S₁ and S₂ determines whether the waves arrive in phase (bright fringe) or out of phase (dark fringe), producing the characteristic alternating fringe pattern.
Concept context
Huygens principle, Young's double slit, diffraction, polarization. Essential for JEE.