1. AP Physics L07_current Effects of moving charges
Electric Current
Effects of moving charges

2. Objectives Relate current, potential and resistance using Ohm’s Law.
Determine the power in a current flow.
Describe the flow of current in a circuit.

3. Electric Current Current = charge flux / time =Dq Dt
Current = charge flux / time =
current
Unit: C / s = ampere = A

4. Question What is the direction of the electric current? A. right
B. left + -

5. Current Density
Vector J
Units: A/m2
I = ∫J·dA

6. Drift Speed Charge carriers are electrons
They move thermally really, really fast
Net velocity giving current (drift speed) is much less than average thermal speed