Answer: Different wavelengths diffract at different angles.
- A Different wavelengths diffract at different angles
- B All wavelengths diffract at the same angle in typical laboratory settings
- C Light is absorbed selectively under usual circumstances
- D The grating polarizes light according to most researchers
Correct answer: A. Different wavelengths diffract at different angles
Explanation: For a grating: d sinθ = nλ. Different wavelengths satisfy this condition at different angles θ, producing a spectrum.
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.