Why eletric charge in Dimensional Analysis and not eletric current?

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SUMMARY

In dimensional analysis, electric charge is classified as a fundamental physical dimension rather than electric current because the Coulomb (unit of charge) is more stable across different reference frames compared to the Ampere (unit of current). The International Committee for Weights and Measures (CIPM) is considering redefining some SI base units based on fundamental constants, such as Avogadro's number and Planck's constant. This discussion highlights the advantages of using charge over current, particularly in relation to relativistic effects, where charge remains invariant while current is frame-dependent.

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  • Understanding of SI base units, specifically Coulomb and Ampere.
  • Familiarity with dimensional analysis concepts.
  • Knowledge of fundamental physical constants, including Avogadro's number and Planck's constant.
  • Basic principles of relativity and its impact on physical measurements.
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  • Research the implications of the proposed SI unit revisions by the CIPM.
  • Study the relationship between electric charge and relativistic effects in physics.
  • Explore the significance of fundamental constants in redefining measurement units.
  • Learn about the historical context and evolution of the SI system.
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Physicists, educators, and students interested in the foundations of measurement in physics, particularly those focused on the implications of dimensional analysis and the SI unit system.

ksio.amaral89
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2 questions,actually:

1-Why in Dymensional Analysis is eletric charge a basic physical dimension instead of eletric current(as Ampere is a SI base unit and Coulomb isn't)?

2-I've read CIPM(or International Committee for Weights and Measures in English) is proposing new definitions for some of the current 7 base units,in which the supporters want to set some of the current definitons based on fundamental constants such as Avogadro or Planck constants.For further information:

http://www.bipm.org/cc/CIPM/Allowed/98/CIPM2009_49_TIMING_THE_NEW_SI.pdf

What's your opinion?Do you consider that the current SI definitions need revisions?
 
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As you know, current is the rate of flow of charge and therefore the unit of charge is simpler than the unit of current. Relativity has a lot to do with charge being a more convenient unit than current as charge is not affected by time dilation so the Coulomb remains the Coulomb whereas the Ampere depends on your frame of reference.
 

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