A Diffraction Grating Is to Be Used to Find the Wavelength

Short Answer

A diffraction grating is to be used to find the wavelength of the emission spectrum of a gas. The grating spacing is not known, but light of a known wavelength of $632.8 \mathrm {~nm}$ is deflected by $43.2 ^ { \circ }$ in the second order by this grating. Light of the wavelength to be measured is deflected by $34.9 ^ { \circ }$ in the second order. What is the wavelength of the light that is to be measured?