this is the procedure of the lab and two questions that I am struggling with are the ones that's been circled.

E2 v X V fx wavelength (mm) A B C D E F 1 Substance 2 Hydrogen colors angle (degrees) angle (radians) wavelength (mm) Wavelength (nm) W Magenta 0 0 0 0 4 Faint Magenta 14.9 0.257132793 0.000428555 428.5546553 UT . Teal 16.8 0.289031797 0.00048172 481.7196616 Red 22.9 0.38912395 0.00064854 648.5399169 8 Mercury colors angle (degrees) angle (radians) wavelength (mm) wavelength (nm) purple 15.5 0.267238376 0.000445397 445.3972935 10 faint green 16.3 0.280666709 0.000467778 467.7778482 11 bright green 19.2 0.328866647 0.000548111 548.1110779 12 yellow 20.5 0.350207381 0.000583679 583.6789688 13 yellow 20.7 0.353474844 0.000589125 589.1247396 14 red 23.6 0.400349033 0.000667248 667.2483876 15 16 Unknown Colors Angle (degrees) angle (radians) Wavelength (mm) wavelength (nm) 17 Orange 0 0 0 0 18 Bright yellow 20.8 0.355106962 0.000591845 591.8449373 19 faint yellow 20.9 0.356737999 0.000594563 594.5633322 20 red orange 21 0.35836795 0.00059728 597.2799159 21 faint red 21.8 0.371367836 0.000618946 618.9463926 22 red 22 0.374606593 0.000624344 624.3443224 23 24 25 d 0.001666667(a) Record the value of the number of lines per mm printed on the grating. For this part of the experiment, use only the first order spectrum. (b) In a table, record the color of the line and the telescope angles (each side of center) for each of the lines in the mercury spectrum. You should be able to resolve several lines: yellow [ green, blue-green (weak) and two violet lines, one considerably weaker than the other (see the table at the end of this lab). There will be a number of other less distinct lines toward the red end of the spectrum. These lines will not be measured. You needn't measure both lines in the yellow doublet. (c) Given the value of d that you were given, check to see if the grating equation is correct. 3. Hydrogen Spectrum (a) Shut off the light source power supply and replace the mercury tube with a hydrogen tube. Measure the telescope angles (each side of center) again for the first order spectrum and record them in a table along with the color of the lines. really a doublet: two lines separated by a narrow gap 14 ce that there has been no cautionary statement made about not disturbing the ition of the grating during this set of measurements. Does it matter if the grating is moved a bit? Can you explain why or why not? (As a test, you can try displacing the grating a bit and then remeasure one of the lines. How does your m value compare with the earlier value?) 4. Unknown Source Obtain a spectrum tube (other than mercury or hydrogen), mount it in the light source power supply and measure the telescope angles (each side of center) several bright lines in the first order spectrum only. If you want, you can be quantitative in this section by calculating the wavelengths of the lines using the grating equation and comparing your wavelengths with the spectrum chart available and attempt to identify the element in the tube. Note that it is vital that your spectrometer has been calibrated to have a very fine and sharp spectral line to make your determination as accurately as possible. However, you can also make a note of all the lines you see and compare to the chart in the room. You will be asked for a qualitative description when you submit your results - and note it need not be perfect! Also note that most of these tubes are different, so you will get different results from other groups. They are unmarked and it is your job to use the spectrometer to determine what the unknown sample is. Analysis 1. Mercury Spectrum For each of the mercury lines observed, calculate a value for the grating spacing d from the grating equation, d sin em = X . Note we set m = 1 since we are only using the first-order spectrum. Tabulate your results. Calculate an average value (and error using the standard deviation!) of d and compare it with the value obtained from the manufacturer's lines/mm printed on the grating. In subsequent analysis, use your average value of d, not the manufacturer's. 2. Hydrogen Spectrum (a) For each of the hydrogen lines, in both orders, calculate the wavelength using your pre- viously determined value of d and the grating equation. Present your results in tabular form. Compare your wavelength values with the accepted values. Be careful about the number of significant figures you report in your results. Is the number consistent with the errors in the measurement process? Comment on these errors. Include your answer to the question posed in part 30 of the procedure. own Source from your examination of the spectrum chart, what is the most likely gas in your unknown source? Are there two that it could be