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Fractional uncertainty and propagation of uncertainties

  1. Mar 5, 2010 #1
    erm, ok lets say i have a value, with uncertainty, like y = 10 ± 3

    so lets say i multiply y by 2, then it becomes 20

    but does the uncertainty becomes 3 x 2 = 6? , hence y = 20±6 ?

    what about divide? does it becomes 1.5?

    i roughly understand fractional uncertainty and propagation of uncertainties, but what if i multiply the value of y with a constant as in the case above. what will become of the uncertainty?

    thanks for help!
     
  2. jcsd
  3. Mar 6, 2010 #2

    Vanadium 50

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    Re: Uncertainty

    Yes, in that case the uncertainty scales.

    Think about it this way - if you know the radius of a circle is 10 ± 3, you don't know the diameter any better than ± 6, right?
     
  4. Mar 6, 2010 #3
    Re: Uncertainty

    ah i see thanks a lot!!!
     
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