Diffraction Grating Formula Interpretation

Steps:

• Recall the standard diffraction grating equation: d sinθ = nλ, where θ is the diffraction angle.
• Rearrange the given equation λ = d sinθ / n to match d sinθ = nλ.
• Identify n as the integer order of the diffraction maximum (n = 1, 2, ...).
• Identify d as the spacing (distance) between adjacent slits in the grating.

Why C is correct:

• In the grating equation d sinθ = nλ, n denotes the order of intensity maxima, and d is the slit separation distance, directly matching the formula's derivation from wave interference.

Why the others are wrong:

• A: n is the order, not the number of slits (which affects resolution but not this equation).
• B: n is the order, not slit number; d is slit spacing, not screen distance (screen distance relates to pattern size via tanθ ≈ x/L).
• D: n is the order, but d is slit spacing, not screen distance.

Final answer: C