Hello, I need help with experimental questions 1 & 2.

Experimental Questions: 1. Why do we use 12' = 2 (known as the Balmer series) in this lab? Why not 12' = 1 (the Lyman series) or n' = 3 (the Paschen series)? 2. Why do we only see 11. = 3 through 12 = 5, and not higher 11.? Part I: Qualitative Observations Plug in your tube and make sure the switch is in the "on" position. Press the button on the handle on the end of the cord; your tube should light up. 1 Put on the diffraction glasses and look at the tube when it is lit up. You should observe a set of colored lines off to the side of the tube (three on either side). 2 3 The rows of lines above and below the tube you can ignore. Hopefully, on the same horizontal axis, you will also observe a second, fainter set of lines, as well; these are the 'm = 2 lines. 4 Answer the questions on the data sheet about your observations from this part. Part II: Measurement of the Rydberg Constant Mount the meter stick on the front of your discharge tube. Put the diffraction grating in the mount, and place the mount about 40cm from the meter stick, oriented facing the tube. Measure and record the distance between 1the front of the meter stick and the gratingl, D. Also note the spacing of the diffraction grating; typically, we use ones that have % 1000, but we also have ones with: 500 hues and; hm. We now want to record the location as of each spectral line (with uncertainties). To dob so, we will makeb use of the LEDs; put one on each side of the meter stick, and turn them on. Look through the diffraction grating, and line up the LED light with the position of the line. 5 Do this on both sides simultaneously for one particular color. Record the position of both the left line and the right line (with uncertainty) for each color. (It is OK if your meter stick moves as you slide around the LEDs, provided both LEDs are in the right place simultaneously for any particular color.) Back to Top _ Part I: Qualitative Interference Behavior In words, explain your observations from this part in terms of formula (4). Part II: Measurement of the Rydberg Constant First, calculate the distance between lines, b. [We had l/b; note that you do not need to include "lines" in your units on b.] Figure out (based on knowledge of how color relates to wavelength, and how wavelength relates to n) which of the lines is 'n, = 3 , which is n = 4, and which is 'n = 5. For each spectral line, calculate the following: - The distance d [as half the separation distance between the two lines], with uncertainty propagated. - The quantity % = tan(9), with uncertainty propagated. - The angle 9 between the tube and the spectral line, then sin(9). (The Google Sheet will do these uncertainty propagations for you. Remember that Sheets, Excel, etc. do all angle measurements in radians.) I The wavelength, A, and the inverse wavelength 1 with uncertainties I A! I The quantity i i (the righthand side of equation (3), except for the Rydberg constant) Make a plot of % vs. "in #. Fit the line through the origin. From the slope, extract the Rydberg constant. Back to Top Measurement of Spectra via Diffraction Recall the formula for the angular location 0m of the mth diffraction peak for light of wavelength 1 passing through a diffraction grating with distance between slits of b: 2 b sin(0m) = md (4) In this lab, we'll be observing the outgoing lines with our eye, and projecting them backwards onto a ruler to observe the angle of diffraction. (Solid lines are real rays of light, dashed lines are projected "virtual" lines of light - the place where you will see the lines coming from.) Meter Stick Hydrogen Tube d Eye ......... Diffraction Grating D Using some basic trigonometry, we can determine that: tan(0) = D (5) By measuring d, we will determine the angle of the m = 1 lines, and thereby the wavelength 1 of each line. We will assume that n' = 2, and that we are seeing the smallest n that turn into n' = 2 (i.e., n = 3, n = 4, and n = 5). This will enable us to relate / to n and thereby determine the Rydberg constant