Hydrogen Emission Spectra Wavelength

[carrico]

Homework Statement

A transmission diffraction grating with 528 lines/mm is used to study the line spectrum of the light produced by a hydrogen discharge tube. The grating is 1.3m from the source (behind a hole in the center of a meter stick). An observer sees the first-order red line at a distance y=0.481063m from the hole.

Calculate the wavelength of the red line in the hydrogen spectra. (do not use small angle approximation) answer in units of m.

Homework Equations

dsin\theta=m\lambda

The Attempt at a Solution

I'm missing the d and the \lambda.So I have two variables and I really don't see any way to sub in for them.

 

[ideasrule]

You have 528 lines in 1 mm, so what's the distance between two lines?