Answer to Question #237722 in Optics for hassan ihtisham

Question

light of wavelength 450 nm is incident on a diffraction grating on which 5000 lines can ruled out determine the angle corresponding to third order

Answer 1

$5000 \;lines/cm = 500000 \;lines/m \\ d = \frac{1}{500000}=2 \times 10^{-6} \\ d \times sin θ = m \times λ$

for third order m = 3

$sin θ = \frac{3λ }{d} \\ sin θ = \frac{3 \times 450 \times 10^{-9}}{2 \times 10^{-6}} \\ sin θ = 0.675 \\ θ = 71.67°$