A laser shined through a diffraction grating with lines that are 1/500 mm apart creates a spectra on a screen. The distance from the center bar to the first side bar is 66 mm. The distance from the diffraction grating to the first side bar is 187 mm. Calculate the wavelength of light (in nanometers) that is being emitted by the laser.

Question

aaronq · Answer

$$n \lambda= d (\frac{ X }{ L })$$

λ = wavelength in nanometers (nm)
d = distance between the lines on the
diffraction grating
n = the order of the image (most often n = 1, this being the first bar/spot to one side of the center spot on the screen)
X = the di stance between the center spot and the first side spot
L = the distance from the diffraction grating to the first side spot