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Experimental negative work function?

  1. Sep 27, 2011 #1
    1. The problem statement, all variables and given/known data
    I have experimentally determined the work function from the intercepts of a fit line in graph of stopping potential (J) versus frequency (Hz). This is from a photoelectric effect lab. The value of the intercept, which I believe is that of the work function, is returned as negative. (the "a" value in the boxes). I know I am getting hung up mentally on a simple sign issue, but why is this value negative? Is this a sign convention indicating energy must enter the material to knock particles (electrons in my case) off?


    2. Relevant equations
    y= bx +a

    Stopping Potential = h*frequency - work function


    3. The attempt at a solution
    My graph is attached.
     

    Attached Files:

  2. jcsd
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