Physic Labs

Problem 3

Monochromatic light of wavelength λ\lambda strikes normally a grating of spacing dd. Find the condition for order kk maxima and the first-order angle. (a) State the assumptions and establish the governing equation for the requested quantity. (b) Solve it in terms of the given symbols, identifying the direction, sign, or physical nature of the result. (c) Check a simple limiting case and state when the model remains valid. Use SI units consistently, retain the symbols in the setup, and enforce all geometric constraints and initial conditions.
dsin⁡θ=kλ,sin⁡θk=kλ/d,∣k∣≤d/λ,θ1=arcsin⁡(λ/d)\boxed{d\sin\theta= k\lambda,\quad \sin\theta_k=k\lambda/d,\quad |k|\le d/\lambda,\quad \theta_1=\arcsin(\lambda/d)}
problems.proof.analysis

The results are listed in the order requested and use one consistent sign convention. Their dimensions, initial conditions, and model constraints must all agree.