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Charges, current, and Electric Field direction?

  1. Dec 5, 2009 #1
    My book says that positive charges drift in the direction of electric field, and negative charges drift in the direction opposite of electric fields

    But wouldn't that depend on if the electric field was generated from a positive or negative charge? How can they just make a generalization like that?

    And it also says that current density is in the direction of current if charge is positive, but opposite if charge is negative...why is that?
  2. jcsd
  3. Dec 6, 2009 #2
    the direction of electric field is from +ve charge to -ve charge
    2nd ans current density=current/area if current is due to +ve charges current is +ve hence current density and vice versa
  4. Dec 6, 2009 #3
    i am also agree with this. also keep in mind that the electric field lines are directed outward in case of +ive charge while directed inward in case of -ive charge
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