1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Why is charge a derived quantity

  1. Feb 4, 2013 #1
    Why is charge a derived quantity????
     
  2. jcsd
  3. Feb 4, 2013 #2
    Re: Charge!

    convention. Current was measured before charge.
     
  4. Feb 4, 2013 #3
    Re: Charge!

    There are seven base units from which all other units are derived.


    -meter (length)
    -kilogram (mass)
    -second (time)
    -ampere (electric current)
    -kelvin (temperature)
    -candela (luminous intensity)
    -mole (concentration of substance)

    Electric charge is measured in Coulombs, or Amperes seconds.
     
    Last edited: Feb 4, 2013
  5. Feb 4, 2013 #4

    jtbell

    User Avatar

    Staff: Mentor

    In SI, current is a fundamental unit (ampere) and charge is a derived unit (coulomb = ampere ยท second) for practical reasons. It's easier to implement the standard for current precisely, by measuring the force between two current-carrying wires, than it would be to implement a standard for charge precisely, involving something like measuring the force between two charges, or counting electrons.
     
  6. Feb 4, 2013 #5

    AlephZero

    User Avatar
    Science Advisor
    Homework Helper

    Re: Charge!

    Ampere seconds, not amperes per second.
     
  7. Feb 4, 2013 #6
    Re: Charge!

    My apologies.
    Edited and corrected.
     
  8. Feb 4, 2013 #7
    No prob. Thanks for that. Really cleared it up
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Why is charge a derived quantity
Loading...