1. Fields 3: Electric Potential Energy

2. How does electric potential energy compare to gravitational potential energy? A gravitational field acts between two masses –Work done against a gravitational field Increases PE –Work done by a gravitational field Decreases PE

3. How does electric potential energy compare to gravitational potential energy? _ ++++ + + + + + + + - - - - - - - - - - + + + + An electric field acts between two charges –Work done against an electric field Increases PE –Work done by an electric field Decreases PE

4. For each of the following: does PE increase or decrease? Opposite charges are brought together:

5. For each of the following: does PE increase or decrease? Opposite charges are brought together: Decrease Like charges are moved apart:

6. For each of the following: does PE increase or decrease? Opposite charges are brought together: Decrease Like charges are moved apart: Decrease Like charges are brought together:

7. For each of the following: does PE increase or decrease? Opposite charges are brought together: Decrease Like charges are moved apart: Decrease Like charges are brought together: Increase Opposite charges are moved apart:

8. For each of the following: does PE increase or decrease? Opposite charges are brought together: Decrease Like charges are moved apart: Decrease Like charges are brought together: Increase Opposite charges are moved apart: Increase

9. What is electric potential difference? The change in PE per unit charge. –How can it be calculated?

10. What is a volt? Unit for electric potential energy (potential difference.) Joules of energy required to move 1c between two points in an electric field. Measured with a voltmeter

11. What is a volt? Ex) 27J of work are required to move a charge of 3c, What is the voltage?

12. What is an electron-volt? Another unit for work The energy required to move 1 electron (or proton) through a potential difference of 1 volt. 1ev = 1.60x10 -19 J (in reference table)

13. Electron Volt Ex) What quantity is equivalent to 4.8x10 -17 joules? a)4.8 ev b)4.8x10 -17 ev c)300 ev d)480 ev

14. Electric Potential difference in a Uniform Field

15. The electric field intensity between two large, charged, parallel metal plates is 6000 N/c. The plates are 0.05 m apart. What is the electric potential difference between them?

16. The electric field intensity between two parallel plates is 4.0x10 4 N/c. If the plates are separated by 5.0x10 -3 m, what is the potential difference of the plates? a)3.0x10 4 volts b)200 volts c)8.0x10 6 volts d)120 volts Example

17. Which has the greater Electric Potential Difference - + - +

18. - + - +