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Homework Help: Photoelectric Effect Graphing, HELP

  1. Aug 9, 2011 #1
    1. The problem statement, all variables and given/known data


    Part 6

    1. Set the cathode metal to copper and light intensity to 50 %.

    2. Tabulate eight values for frequency and photoelectron energy in Joule.

    3. Draw a graph of frequency and photoelectron energy.

    4. Use the graph to calculate a value of Planck’s constant h. On the graph, show the points that you used in the calculation. Include the units.

    5. On the graph, label the threshold frequency and the work function.

    2. Relevant equations

    Run the Java.

    3. The attempt at a solution

    1. done

    2.i have calculated 8 frequences, not sure how i would go about converting ev to joules for this problem. I know you devide by (ev) (1.6x10^19), this will give me Joules.

    3. cant do without (2)..

    4. i have gathered information from the text books on how i would go on about calculating the value of plancks constant. Coming to the conclusion that it invloves obtaining the slope from the graph (3) nad using the slope.

    Energy = hf - W
    Vs x e =hf -W
    Vs = (h/e)f - W/e

    5. Threshold Function -This is where the function comes into contact with the X Axis.
    Work Function - y int.

    I thank you in advance, any advice on obtaining the graph would be greatly appreaciated.

  2. jcsd
  3. Aug 9, 2011 #2


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    Homework Helper

    The conversion factor eV to Joules is in fact 1.6 x 10 ^ (-19) [ie minus 19]

    Since the Joule answer is smaller [much, much smaller] that the eV value - how would you use that factor to get a smaller answer? multiply or divide?

    EDIT: everything else you said was fine.
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