Answer:
The light’s wavelength is 500 nm
Explanation:
mλ = d*sin(θm)
where;
λ is the visible light wavelength (nm) = ?
d is the groove (slit) spacing (mm/lines) = 1/500mm
θm is the angle of refraction
m is is the diffraction order, for visible light range, m = 2
λ = [d*sin(θm)]/m
λ = (sin30)/(500*2) = (0.5)/(1000) = 0.0005 mm = 500 nm
Therefore, for a diffraction grating having 500 lines/mm and diffracts visible light at 30°. The light’s wavelength is 500 nm