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Homework Help: About ohm law can't be applied

  1. Oct 12, 2009 #1
    1. The problem statement, all variables and given/known data
    Given I = Io (exp (V/Vo) -1), Io = 1 A, Vo = 1 V, R = 1 ohm
    (i) Find R when V = 5 Volt
    (ii) Find R when V = 10 Volt
    (iii) Plot the graph of V vs I
    (iv) Explain why the Ohm’s law can’t be applied

    2. Relevant equations
    V = I*R

    3. The attempt at a solution
    (i) Subs. to the equation given, i got I = (e^5 ) - 1. Then R = V / I = 5 / [(e^5 ) - 1] ohm

    (ii) Use the same method as (i), I got R = 10 / [(e^10 ) - 1] ohm

    I'm not sure I can use V=I*R, but I don't know the other way to find R

    (iii) the graph will be exponential curve similar to y = e^x

    (iv) The Ohm's law can't be applied because the relation between V and I is not linear.

    Do I get it right?

  2. jcsd
  3. Oct 12, 2009 #2


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    Homework Helper

    Even in a non-ohmic circuit, you can the ohm's law at a particular instant.
  4. Oct 12, 2009 #3
    Hi Mr. rl.bhat

    Ok then I think my answers are right. Thanks
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