Electric Forces and Fields/Electric Potential

1. Electric Potential Energy

1.1. Energy stored in an electric field

1.2. Ue=k(q1*q2)/r

1.3. Signs of Charges determine sign of PE

2. Electric Potential

2.1. Electric potential energy per unit charge

2.2. V=U/q

2.3. 1V=1 J/C

2.4. Potential Difference: change in electric potential energy/unit charge

3. Electric Field and Potential:

3.1. Equipotential Surface

3.1.1. Same potential at every point on the surface

3.1.2. perpendicular to electric field lines at all points

4. Coulomb's Law

4.1. F= k(q1xq2)/r2

4.1.1. k=8.99e9

4.2. F=electrical force each charge exerts on the other

5. Properties of Charge

5.1. *Law of Conservation of Charge*: net charge of a closed system never changes.

5.2. Like Charges repel one another, unlike charges attract one another

6. Means of Charging/Discharging

6.1. Conduction: some charge can move easily

6.2. Charging a conductor: Rubbing

6.3. Semiconductor: intermediate between insulator/conductor

6.3.1. Photoconductor: uses light--no light=insulator, light=conductor

6.4. Insulator: charge does not move easily

6.4.1. Glass, plastic, rubber, wood

6.5. Grounding: process of discharging a conductor

7. Calculations

7.1. Electrical Field(E)=Electric force(F)/q

7.2. F=(k*q*Q)/r2

7.2.1. Q=single point charge

7.3. Electric Force(F)=Electrical Field(E)xq

8. Electric Field Lines

8.1. Postive Charge: Lines go away from center

8.2. Negative Charge: Lines go toward center