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Proportionality relationship and how to convert using it

  1. May 20, 2015 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    Please see below.

    3. The attempt at a solution

    The idea is to find Bmin. We know: $$
    \tau \frac{eB}{m}\gg 1 \\ \\

    \rightarrow \frac{eB}{m}\gg \tau$$


    [1] We are given $$\tau \propto \frac{1}{T^{2}}$$ .

    [2] We are also given a conversion factor $$\tau =10ns \ at \ 1K$$.

    Now, how would you use [1] and [2] to convert 300K?

    I'm assuming you can't just use [2] and do $$300K\cdot \frac{10ns}{1K} = 3X10^{-7}s$$ because of the non-linear relation given in [1].

    Am I just confusing things?

  2. jcsd
  3. May 20, 2015 #2


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    Homework Helper

    You are told that [itex]\tau = CT^{-2}[/itex] for some constant [itex]C[/itex], and are given sufficient information to determine [itex]C[/itex].
  4. May 21, 2015 #3
    Ahhh, don't know why I didn't think of it like that! Many thanks!!
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