1. QUARTER 4
Electric Fields

2. Reminder:
Remind me about the idea of ELECTRIC FORCE, with equations, variables, etc.

3. Find the:
Magnitude of electric force between 16 protons and 7 electrons that are .44 meters away.

4. A negative charge of -6C exerts an attractive force of 65N on a second charge .05m away.
What is the magnitude of the second charge in coulombs?

5. A charge that is ‘fixed’

6. A field that is ‘fixed’

7. Electric Fields By definition, the are “LINES OF FORCE”
Some important facts:
An electric field is a vector
Always is in the direction that a POSITIVE “test” charge would move
The amount of force PER “test” charge
If you placed a 2nd positive charge (test charge), near the positive charge shown above, it would move AWAY.
If you placed that same charge near the negative charge shown above it would move TOWARDS.

9. The -2Q has a force LEFT (against the field), the +Q has a force RIGHT (with the field). Therefore this thing is going to rotate, but since the fields are the same amount at each charge, the forces cancel out and the net force is zero. Is this correct/incorrect/partially correct?

10. An explanation

12. Lets Draw…Two Positives

13. How would 2 negatives look?

15. Now try…

16. Proportions…
A +4C and a -2C charge

17. If A is +9C, what is the sign and amount for B?