The accurateness of electricity laws

  • Context: Undergrad 
  • Thread starter Thread starter MHD93
  • Start date Start date
  • Tags Tags
    Electricity Laws
Click For Summary

Discussion Overview

The discussion revolves around the accuracy of electrical laws, particularly Ohm's law and Maxwell's equations, in comparison to mechanical laws. Participants explore whether these laws are exact or merely approximations, considering ideal conditions and the implications of quantum mechanics.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether electrical laws are as accurate as mechanical laws under perfect conditions or if they are just good approximations.
  • Another participant asserts that Maxwell's equations are highly accurate, potentially more precise than current measurement capabilities, suggesting that the limitations arise from our inability to input exact parameters.
  • A different participant expresses a focus on the laws mentioned in the initial post, indicating a desire for clarification on those specific laws.
  • It is noted that Maxwell's equations serve as approximations to quantum electrodynamics (QED), applicable when quantum effects are negligible, with no known electromagnetic phenomena that QED cannot accurately model.
  • One participant states that Ohm's law is fundamentally a definition of resistance, implying its inherent truth.
  • A follow-up question is raised about whether ohmic materials maintain perfectly linear relationships between voltage and current.
  • Another participant clarifies that while resistance is defined as V/I, it can vary based on multiple factors such as voltage, current, temperature, pH, and illumination.

Areas of Agreement / Disagreement

Participants express differing views on the nature of electrical laws, with some asserting their accuracy and others highlighting their limitations and dependencies on various factors. The discussion remains unresolved regarding the extent to which these laws can be considered exact.

Contextual Notes

Participants acknowledge that the accuracy of electrical laws may depend on specific conditions and definitions, and there are unresolved questions about the linearity of relationships in ohmic materials.

MHD93
Messages
93
Reaction score
0
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.
 
Physics news on Phys.org
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.
 
Well, that was helpful, but I am more concerned to the laws mentioned in post #1
 
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.
 
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
 
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.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 11 ·
Replies
11
Views
921
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 29 ·
Replies
29
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K