Another Wave Length question

1. Nov 23, 2006

quickslant

Lights with wavelengths of 520 nm and 630 nm passess through a diffraction grating that contains 6000 lines/cm or 600000 lines/m

what is the lowest value of m for which the 520 nm line no longer exists?

2. Nov 23, 2006

quickslant

3. Nov 23, 2006

Kurdt

Staff Emeritus
Do you know any equations relating to diffraction gratings?

4. Nov 23, 2006

quickslant

sin theta(m) = m(wavelength)/ d

5. Nov 23, 2006

Kurdt

Staff Emeritus
Well all you have to do is find out how many orders you can get for that wavelength. You know when it disappears when $$\theta_m$$ is greater than 90 degrees.

6. Nov 24, 2006

quickslant

thank you very much..