Problem 5: A diffraction grating has 5000 lines per centimeter. At what angle does the second order spectrum of the sodium yellow light of wavelength 589 nm occur?
No of lines = N = 5000/cm = 500000/m
Grating element = d = 1/500000 = 0.2 * 10-5 = 2 * 10-6
No of order = m =2
Wavelength of the light used = 589 nm = 589 * 10-9 m
Put the values,