The accurateness of electricity laws

[MHD93]

Are the mathematical electrical laws as accurate as mechanics laws, if the input is perfect enough, or they're just good approximations??

I mean ohm's law and potential difference = electric field times length of wire (in wires), and alike laws.

 

[Mu naught]

All of maxwells equations are fantastically accurate - more than the precision of our measurements.

Depending on your philosophy on this subject, you can say that maxwells laws describe exactly electromagnetic behavior, but that we are never able to input the exact parameters needed for an exact answer.

 

[MHD93]

Well, that was helpful, but I am more concerned to the laws mentioned in post #1

 

[Dale]

Maxwell's equations are approximations to quantum electrodynamics (QED) which are suitable whenever quantum effects are not important. AFAIK, there are no known EM phenomena which are not correctly modeled by QED.

Ohm's law is essentially just the definition of resistance, so it is true by definition.

 

[MHD93]

Ohm's law is essentially just the definition of resistance, so it is true by definition.

OK, for the sake of making the question clearer, Do ohmic materials have perfectly linear relationships of V/I

 

[Dale]

No. The resistance is always V/I, but the resistance may itself be a function of voltage or current or temperature or pH or illumination or many other factors.