The picture above shows the measurement method based on the diffraction formula
nl = d sin q
Students measure x (distance between the central and the first maximum) and L (distance between the diffraction grating and the screen). Despite very simple methods, the results are accurate. The table below presents the results. Percent error is calculated between the experimental value and the 680 nm red diode laser.
Table by Nicole, Marya, and Rudemy.
