1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lab Exercise: How do I make a logarithmic curve linear?

  1. Jan 28, 2011 #1
    1. The problem statement, all variables and given/known data
    In a certain experiment, the power (P) radiated by a light bulb filament was measured as a function of the filament's absolute temperature (T).

    Data:
    P(W)
    0.45
    0.95
    1.8
    3.5
    5.6

    T(K)
    1000
    1200
    1500
    1800
    2000

    (a) Plot the data (Done)

    (b) Assume a power function and re-plot the data.

    2. Relevant equations

    Unsure.

    3. The attempt at a solution

    I plotted the data and it looks like a natural logarithm. I'm not sure what to do next. Raising each T value to the power of 2 straightens out the curve a bit but not completely. Is that what it means to assume a power function? If a power function is y=kx^a, how do I know which exact a to take and where do I get k from? Thanks.
     
  2. jcsd
  3. Jan 28, 2011 #2

    Delphi51

    User Avatar
    Homework Helper

    Suppose P = T^n.
    Then ln(P) = ln(T^n) = n*ln(T).
    If you graph your data as ln(P) vs ln(T), (and the data is perfect) you will get a straight line with slope n. Imperfect data (isn't it always?), the slope of a trend line is the best value for n.
     
  4. Feb 1, 2011 #3
    Thank you. That was what my professor was looking for.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Lab Exercise: How do I make a logarithmic curve linear?
  1. How do i make a FAN? (Replies: 2)

Loading...