Answer: θ_min = 1.22λ/D.
- A θ_min = 1.22λ/D
- B θ_min = λ/D
- C θ_min = D/λ
- D θ_min = 2λ/D
Correct answer: A. θ_min = 1.22λ/D
Explanation: Rayleigh criterion: two objects are just resolved when the central maximum of one falls on the first minimum of the other. θ_min = 1.22λ/D.
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.