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Is Ohm's Law applicable for only DC or for both?

  1. Dec 12, 2014 #1
    Is ohm's law (V=IR) works for both AC and DC. PLz explain in details

    Also let me know which formula is right for power calculation for AC and DC circuits. (P=VI or P=VICos)
  2. jcsd
  3. Dec 12, 2014 #2
    ohms law is valid for both ac and dc . but the v=ir form is not actually the ohms law . this form is only valid for dc .
    in AC we use the actual expression ..
    J is current density
    sigma is conductivity
    E is electrif field

    for dc p=vi=v^2/r=i^2*r can be used
    the other one mentioned by you is for ac.

  4. Dec 12, 2014 #3
    dc: V = I*R, R = resistance
    ac: V = I*Z, where Z = R + jX, X = reactance, Z = impedance

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