1. ELECTRIC FIELDS AND POTENTIALS
THE NEXT STEP

2. ELECTRIC FIELDS THE FORCE FIELD THAT SURROUNDS A CHARGE.
EXAMPLE - VAN DE GRAPH GENERATOR
ANOTHER TYPE OF FIELD IS GRAVITATIONAL FIELD.

3. ELECTRIC FIELD
THE SPACE AROUND EVERY ELECTRIC CHARGE IS FILLED WITH A FORCE DUE TO THE ELECTRIC CHARGE AND WE CALL THIS THE ELECTRIC FIELD.
THIS FORCE CAN BE DESCRIBED BY THE INTERACTION BETWEEN ONE CHARGE AND THE ELECTRIC FIELD SET UP BY THE OTHER.

4. ELECTRIC FIELD LINES
ELECTRIC FIELDS HAVE:
DIRECTION
MAGNITUDE

5. MAGNITUDE MAGNITUDE- MEASURED IN N/C OR V/m
MEASURED BY USING A SMALL TEST CHARGE IN AN ELECTRIC FIELD. THE FORCE IS THE STRONGEST WHERE THE FIELD IS THE STRONGEST AND THE WEAKEST WHERE THE FIELD IS THE WEAKEST.

6. DIRECTION
THE DIRECTION OF THE ELECTRIC FIELD IS FROM POSTIVE TO NEGATIVE.
THE ELECTRIC FIELD JUST OUTSIDE A CHARGED CONDUCTOR IS PERPENDICULSR TO THE CONDUCTOR’S SURFACE.
AN IRREGULARLY SHAPED CONDUCTOR,

7. ELECTRIC FIELD LINES ALSO CALLED LINES OF FORCE
REPRESENT THE STRENGTH OF THE MAGNETIC FIELD.
THE MORE LINES THE STRONGER THE FIELD.
NO TWO FIELD LINES CAN CROSS EACH OTHER. + -

8. OPPOSITE CHARGES
FROM POSITIVE TO NEGATIVE - +

9. LIKE CHARGES
LIKE CHARGES REPELL + +

10. PLATES
POSITIVE TO NEGATIVE -

11. ELECTRIC SHIELDING
ON A HOLLOW OBJECT CHARGE IS DISTRIBUTED EVENLY ON THE OUTSIDE SURFACE.
THE ELECTRIC FIELD IS OUTSIDE THE SPHERE
THE ELECTRIC FIELD INSIDE THE SPHERE IS ZERO.

12. NONSPERICAL OBJECTS
THE ELECTRIC FIELD WILL NOT BE DISTRIBUTED EVENLY. IT TENDS TO BUILD UP AT SHARP TURNS OR CORNER.
THE ELECTRIC FIELD INSIDE WILL STILL BE ZERO.
HOLLOW OBJECTS ARE USED TO SHIELD SENSITIVE ITEMS.

13. CAN YOU SHIELD GRAVITY?
THERE IS NO WAY TO SHIELD GRAVITY BECAUSE GRAVITY ONLY ATTRACTS.
GRAVITY CAN BE CANCELED INSIDE A PLANET OR BETWEEN PLANETS.

14. POTENTIAL ENERGY REMEMBER: WORK = CHANGE IN K.E. F X D = ½ MV2
CHANGE IN P.E. = CHANGE IN K.E.

15. ELECTRIC POTENTIAL ENERGY
CHARGES CAN HAVE P.E. BY VIRTUE OF WHERE THEY ARE LOCATED WITHIN THE ELECTRIC FIELD.
WE CALL IT ELECTRIC POTENTIAL ENERGY.
IF A CHARGE IS HELD STILL IN AN ELECTRIC FIELD IT WILL HAVE ELECTRIC POTENTIAL ENERGY, WHEN IT IS ALLOWED TO MOVE, THE P.E. WILL CONVERT TO K.E.

16. ELECTRIC POTENTIAL
THE TOTAL ELECTRICAL POTENTIAL ENERGY DIVIDED BY THE AMOUNT OF CHARGE.
AT ANY LOCATION THE P.E. PER CHARGE WILL BE THE SAME.
ELECTRIC POTENTIAL IS MEASURED IN VOLTS.
COMMONLY CALLED VOLTAGE FOR ALESSANDRO VOLTA – FAMOUS FOR CREATING BATTERIES.

17. EQUATION ELECTRIC POTENTIAL = ELECTRICAL POTENTIAL ENERGY/CHARGE
V = W/Q
1 VOLT = 1JOULE/COULOMB

18. ELECTRIC POTENTIAL ENERGY V.S. ELECTRIC POTENTIAL
ELECTRIC POTENTIAL ENERGY BUILDS ON THE OUTSIDE OF THE VAN DE GRAFF GENERATOR.
CAN YOU TAKE THE CHARGE OFF OF THE GENERATOR WITHOUT HURTING YOURSELF?
ELECTRIC POTENTIAL PROVIDES THE ELECTRON FLOW TO POWER THE GENERATOR.
CAN YOU TOUCH A BARE WIRE COMING FROM THE OUTLET TO THE GENERATOR WITHOUT BEING HURT?

19. CAPACITANCE ELECTRICAL ENERGY STORAGE STORED IN A CAPACITOR
CAPACITOR – A SET OF PLATES SEPARATED BY A SPACE.
THE CHARGE IS STORED BETWEEN THE PLATES.
THE ENERGY STORED COMES FROM WORK REQUIRED TO CHARGE IT.
DISCHARGE OF A CAPACITOR CAN BE A SHOCKING EXPERIENCE.

20. FOLLOW UP QUESTIONS PHYSICS – PAGE 529; 1-20
PRE AP PHYSICS – PAGE 642, 1-5; 652, 1-5; PAGE 654, 1-10
ANSWER IN COMPLETE SENTENCES