Answer: Comparable to the wavelength of light.
- A Comparable to the wavelength of light
- B Much larger than the wavelength
- C Much smaller than the wavelength
- D Exactly twice the wavelength
Correct answer: A. Comparable to the wavelength of light
Explanation: Diffraction is significant when the obstacle or aperture size is comparable to the wavelength. For visible light (~500 nm), slits of this order show clear diffraction patterns.
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.