How can we decide the direction of electric current in a conductor?

electric-current

#1

We know I = nq$A{{v}_{d}}$. In this n and A are positive. Hence the direction of current is determined by the signs of the charge ‘q’ and drift speed vd.

  1. For electrons, q is negative and vd is positive. Then the product of q and vd is negative. So the direction of electric current is opposite to the flow of negative charge.
  2. For positive charges, the product of q and ${{v}_{d}}$ is positive. Hence, the direction of electric current can be taken as the direction of flow of positive charges.