YOU MUST SHOW ALL CALCULATIONS TO RECEIVE CREDIT FOR THEM!

Calculations:

• Prepare a plot of energy vs. (1/wavelength) for Hg, H₂ and Ne graph by using excel.
• Calculate slope of the best fit line for each gas, show your calculations in your lab report sheet, computer calculated answer will not be accepted.
• • Calculate the Planck’s constant for each gas by using the slope from each graph and following the example shown in the lab manual.

   

   

   

   

  Example calculation of slope from Hg graph:

  X₁ = 1.83 x 10^-3  y₁= 2.30 eV

  X₂ = 2.20 x 10^-3  y₂= 2.70 eV

  Y₂-Y₁   =         2.70 eV– 2.30 eV                         =  1066.7eV nm

  X₂-X₁     (2.20 x 10^-3 nm^-1) – (1.83 x 10^-3 nm^-1)

   

  Unit conversions:

  1067 eV nm  x  1.00 x 10^-9 m  x  1.602 x 10^-19 J  = 1.71 x 10^-25 Jm

  1nm                     1 eV

  h = slope/c = 1.71 x 10^-25 Jm    = 5.70 x 10^-34 Js

•            2.998 x 10⁸ ms^-1

   

  Calculations and Excel Graphs (you can use as much space as needed):

  Discussion questions

   

  1. Show the calculation of Planck’s constant, mentioned in calculations #3 (in your book, page #61, printed version), including the unit conversion for mercury, hydrogen and neon. 
     1. Using Equations 1 and 2 from the introduction (page 57 in lab manual, printed version), derive the equation that will allow you to find Planck’s constant from your graph.

      

      

      

      

      

      

      

      

     2. Average all of the calculated values of Planck’s constants you obtained. Calculate the percent error of this value compared to the accepted value of Planck’s constant.

      

     1. Compare the averaged value of Planck’s constant determined in discussion questions 3 to the accepted value of Plank’s constant. Did you obtain a value of Planck’s constant that was within ±10% of the literature value? If not, explain why. Does averaging many experimental observations create a more accurate constant? Explain.