An astronomer is calibrating a spectrometer that uses a diffraction grating to separate light in order of increasing wavelength (A, B, and Ac). She observes three distinct first-order spectral lines at the following respective angles m (where m denotes order 8 = 12.6, 6 = 13.9, e = 14.9 (a) If the grating has 3,700 grooves per centimeter, what wavelength (in nm) describes each of these spectral lines? at 6 = 12.6 at 8 = 13.9 0, at = 14.9 28 = = nm nm nm (b) At what angle (in degrees) would each of these lines be found in the second-order spectrum? for 2 for d for c2