1. Electric Field
Physics
Mr. Dellamorte

2. Analogy The electric field is the space around an electrical charge
just like
a gravitational field is the space around a mass.

3. Electric Field
Space around a charge.

4. What is the difference?

5. Electric Field Lines

6. Electric Field Lines of two Positive Charges

7. Rule #1 From positive to negative
Electric fields always move away from positive charges.
Electric fields always move towards negative charges
From positive to negative

8. Rule #2
More field lines mean increased field strength.

9. Rule #3
Electric Field Lines NEVER cross.

10. Rule #4
There is a region between 2 like charges that will have no electrical field. (looks like a diamond.)

11. Electric Field Lines Review
Electric fields always move away from positive charges.
More field lines mean increased field strength.
Electric Field Lines NEVER cross.
There is a region between 2 like charges that will have no electrical field. (shaped like a diamond)

12. Which field is stronger?
A B

13. Electric Field Strength, E
E = F/ q
q , positive test charge
E is a vector quantity
Unit: N/C
E is analogous to the gravitational field, g, where g=F/m

14. Electric Field Strength, E
E = kQ/d2
This is a combination of Coulomb’s Law and the Electrical Field equation.
It allows us to find the electrical field of a charge at different distances.
K = 8.99 x 109 Nm2/C2
Q = charge In Coulombs (C)
D = distance from charge in meters (m)

15. Example 1
A charge of 3µC is used to test the electric field of a central charge of 6C that causes a force of 800N. What is the magnitude of the electric field?
Answer: 2.7 x108 N/C