1. The field lines for a positive point charge
The field lines for a positive point charge.   The lines flow out from the positive charge
The field lines for a negative point charge.   The lines flow in towards the charge
The field lines for two positive point charges.   The field lines flow away from both charges.
The field lines for one positive point charge and one negative point charge.  The field lines flow out of the positive charge and into the negative charge

2. Electric field lines never cross.
The electric field can be represented by field lines. These lines start on a positive charge and end on a negative charge.
The number of field lines starting (ending) on a positive (negative) charge is proportional to the magnitude of the charge. E
The electric field is stronger where the field lines are closer together. A B C E
Electric field lines never cross.
Electric field lines are drawn perpendicular to a surface outside of a conductor.

3. To double the force on a given particle…

4. Electric field of two charges:
The electric field between two closely spaced, oppositely charged parallel plates is constant.

5. Summary of field lines:
Field lines start on positive charges and end on negative charges; the number is proportional to the magnitude of the charge.
The magnitude of the field is proportional to the density of the lines.
Field lines indicate the direction of the field; the field is tangent to the line.

6. Electric Fields and Conductors

7. Electric Fields and Conductors
The electric field is perpendicular to the surface of a conductor
The electric field is zero inside a conductor (hollow or solid) E=0
Any net charge on a good conductor is distributed equally on the surface.

8. Why do you think this happens?
Charged Conductors
Any excess charge ends up on the surface of a conductor, independent of its shape
Why do you think this happens?
© Laura Fellman

10. the Electric Field at any point within a conducting material is zero.
What happens to a neutral conductor placed in an external electric field?
E = 0
“Shielding”
the Electric Field at any point within a conducting material is zero.
© Laura Fellman