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## Homework Statement

A common method for finding wavelength is to use diffraction grating. The relationship between wavelength λ and the angle of max intensity θ for first order interference is λ = d*sinθ where d is the spacing between lines on the grating, which is the inverse of the grating line density N (d=1/N). This data was taken on a laser of unknown wavelength:

N = 602 ± 2 lines/mm

θ = 22.4°± 0.4°

## Homework Equations

Δλ = √[ ( Δd*∂λ/(∂d) )

^{2}+ Δθ*∂λ/(∂θ) )

^{2}]

σ

_{x}= (w/2)/√6 ~ pdf uncertainty for analog measurements // I wouldn't think this is needed, since it's for measurements with calibration uncertainty...right?

## The Attempt at a Solution

Well, the above equation is part of the attempt.

The partial with respect to distance (d) is sinθ.

The partial with respect to θ is d*cosθ.

∴ Δλ = √[ ( 2*sin(22.4°) )

^{2}+ 0.4*cos(22.4°)/602 )

^{2}] = 0.762

λ = 6.33 ± 0.762 mm