You are a researcher in a top UBC lab, and find yourself needing a monochromator. You borrow an old one from Dr. Zeuss' lab, but find out that the wavelength selector control is broken. The 'hundreds' digit has been dissolved! If, for example, it reads X18nm, it could mean any of 218, 318, 418, ... , 718 nm! On top of that, you don't know the line spacing of the grating. Even so, you really need to do your experiment, so you decide to calibrate the monochromator. You set the wavelength selector to a value, shine in a white light source, and determine that for an incidence angle of 50.13 degrees, you observe first-order diffraction at -10 degrees. Then, you decrease the wavelength selector down to the next hundred mark (ie. 100 nm less than the previous value used), and, using the same light source, determine that for an incidence angle of 52.19 degrees, you observe first-order diffraction at -18.68 degrees. Determine the line spacing of the grating in nm