# Differences

This shows you the differences between two versions of the page.

Though not to 13 digits of precision (!), you are going to measure the Rydberg constant by plotting $\Large{\frac{1}{\lambda_n}}$ vs. $\Large{\frac{1}{2^{2}}-\frac{1}{n^{2}}}$ .  Though not to 13 digits of precision (!), you are going to measure the Rydberg constant by plotting $\Large{\frac{1}{\lambda_n}}$ vs. $\Large{\frac{1}{2^{2}}-\frac{1}{n^{2}}}$ .
-The Lab pretest asks you to calculate the value of  $d$  because you need it for the analysis of your data. You obtain the value of  $d$  from knowing that the number of grooves per inch for the diffraction grating is 13,​400. ​ Calculate the spacing in meters between the grating grooves to get your value of  $d$ .  Be careful with units! ​ Not only do you have to convert from inches to meters, but you also must notice that the units of grooves per inch is one over length, in //SI units//, m$^{-1}$.  ​+The Lab pretest asks you to calculate the value of  $d$  because you need it for the analysis of your data. You obtain the value of  $d$  from knowing that the number of grooves per inch for the diffraction grating is 13,​400. ​ Calculate the spacing in meters between the grating grooves to get your value of  $d$ .  Be careful with units! ​ Not only do you have to convert from inches to meters, but you also must notice that the units of grooves per inch is one over length, in //SI units//, m$^{-1}$.  ​
Move the diffraction grating to ~ 60 cm from the discharge tube. This is the distance ​ $y$ in the earlier figure that defines the geometry of your setup. Record ​ $y$  accurately along with an estimate of its uncertainty. Move the diffraction grating to ~ 60 cm from the discharge tube. This is the distance ​ $y$ in the earlier figure that defines the geometry of your setup. Record ​ $y$  accurately along with an estimate of its uncertainty.