Download Test Charge - physics1516

Warm Up
1) What is the SI unit for charge?
2) Calculate the electric force
between two electrons that are
1.0 mm apart.
Electric Field Lines
Electric Field
 A measure of the electric force a positive test charge
would feel at any location
 Test Charge – a unit charge used to measure the field
 (There need to be two charges involved – one creating
the electric field, Q, and the other that feels its effects,
q.)
The farther apart the field
lines, the weaker the force
Electric Field
 E = Fe / q
 Units: N/C
 E represents the strength of the electric field
 Q is the charge of the particle FEELING the field
 Ex: A positive charge of 1x10-5 C experiences a force of
0.2 N when located at a certain point in an electric field
created by a point charge of 3.4x10-3C. What is the
electric field strength at that point?
Drawing electric field
lines
Another try:
Copy this view of one positive charge and one negative
charge, and draw the electric field you think they’d
create…
Hint: which one is the field going away from?
And toward which one?
Electric dipole field
Parallel plates that are
oppositely charged
The electric field is the same at all
points between parallel plates
What two things does an
electric field tell us?
 Magnitude
 Direction