Halliday, Resnick & Walker — Diffraction: Problem 32

32 With light from a gaseous discharge tube incident normally on a grating with slit separation \(1.87\ \mu\text{m}\), sharp maxima of green light are experimentally found at angles \(\theta = \pm 17.6^{\circ}, 37.3^{\circ}, -37.1^{\circ}, 65.2^{\circ}\), and \(-65.0^{\circ}\). Compute the wavelength of the green light that best fits these data.