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Electric power = I2*R= (0)2*infinity = can be any thing for open circuit?

  1. Nov 5, 2014 #1
    In an open circuit resistance is infinity and therefore current is zero.(voltage 220V)
    power=iv=0*220=0 watt
    power=I2*R=(0)2*infinity=can be any thing (V=IR)
    so,is power consumed zero or any thing?
     
    Last edited by a moderator: Nov 5, 2014
  2. jcsd
  3. Nov 5, 2014 #2

    CWatters

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    A resistor dissipates power in the form of heat (eg it gets warm or even hot). Would an open circuit get hot?
     
  4. Nov 5, 2014 #3

    CWatters

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    power=I2*R

    Consider what happens as R approaches infinity and I approaches zero. Lets say you start with some value of R and then keep doubling it. At each step the current halves but the power changes by how much ? Work it out.
     
  5. Nov 7, 2014 #4
    Here the current does not tend to zero but is exactly 0. Hence, 0*R where R tends to infinity is exactly zero, not just any value. So power dissipated must be zero. if i would have tend to zero, i.e, went very near zero then i*Rwould have taken any value..
     
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