A diffraction grating has 500 lines per millimeter. What is the angle of the second-order maximum for light of wavelength 500 nm?
Correct: A
The grating spacing d = 1 / (500 lines/mm) = 2 x 10⁻⁶ m. The grating equation is d sin(θ) = nλ. For n = 2, sin(θ) = (2 * 500 x 10⁻⁹ m) / (2 x 10⁻⁶ m) = 0.5. Thus, θ = sin⁻¹(0.5) = 30 degrees.