Wavelength of monochromatic light


To Measure the wavelength of monochromatic light




Formula: nλ = d Sinθ.         n=fringe order . d=diffracion grating. θ=angle of diffraction

                        d=500 lines per mm. Then d for formula = 1/500,000 = 2x10-6 m.



Spectrometer setup: Focus telescope on distant object. Ensure base & stage are level, Adjust slit width.


Errors =Crosshairs in centre of ray? Error Vernier scales, diffraction grating not completly perpendicular to stage.


Accuracy = The smaller the gap in the D.G the larger the diffraction and the lower the percentage error when measuring the angles.