1. As with any tool in the lab, you need to calibrate the instrument using a known reference. For a spectrometer you can use a laser, with a known wavelength as a light source. So for instance if you used a laser with  = 532 nm and you find that the first order maximum for the diffraction grating being used in your spectrometer is observed at  = 25°, what is the spacing, d, between the slits for this diffraction grating? How many slits are there per mm?