1.  There is both a left and a right position for each order of the sodium lines, and you should average these angles for a given order in cells D13:D16. With eqn. (5) and the known wavelength of the sodium yellow lines, use this average angle value to calculate d (mm/line) for each order and enter in cells E13:E16. Then average the values of d from all orders obtained and enter in cell E17. Calculate the standard deviation in this value and enter this value as the uncertainty Δd in cell G17.

2.  Calculate the value of 1/d (lines/mm) for the grating, and enter the result in cell E19. Find the percentage difference between your measurement and the nominal value of 300, and enter the result in cell E21.

3.  Use the average d-value just obtained and the averaged angular data from the hydrogen spectrum to determine the wavelengths of the hydrogen lines. Enter the results where indicated in the Table in cells F27:F29 and F33:F35. Estimate the uncertainty in these values and record the results in the table. Compare to the "accepted" values given, and compute the percentage error in each case in cells G27:G29 and G33:G35.

4.  ♦♦♦ OPTIONAL ♦♦♦
Repeat the above analysis for the helium spectrum. Enter the results for the measured wavelengths in cells F42:F50 and F54:F62. Compute the percentage error and enter in the Table in cells G42:G50 and G54:G62.

5.  On a separate sheet of paper, draw a sketch of the hydrogen spectrum with colored pencils. This series of lines is the result of transitions from energy levels with n > 2 to the n = 2 level. Not all such transitions are in the visible part of the spectrum.