Electric Potential Energy Electric Potential Energy results when we move, push, or force charged particles against their will. + + We have to do work to move a charge against its will. Work done by me = Energy gained by particle SI Unit for Energy: Joules (J)

Electric Potential Energy Electric Potential Energy results when we move, push, or force charged particles against their will. + + Work done by me = Energy gained by particle Acts like a spring EPE Kinetic Energy KE = ½ mv 2

Electric Potential Energy Examples of Work done by me/Energy gained by the particle…..

Example 7 A proton gains 3.50 x J of electric potential energy in an electric field. What will be the maximum velocity of the proton once it is free to move? *Give a scenario in which a proton would be able to gain EPE.

Equipotential Lines How can we capture the ‘steepness’? Mount Everest *Lines represent changes in elevation *What does it mean if you stay on one line?

Equipotential Lines Equipotential Lines - Line on which all points have the same electric potential Equipotential lines - always perpendicular to electric field lines

Electric Potential Difference Test charges placed near a point source will move from one electric potential to another Positive Test Charges - Naturally move from high to low electric potentials Negative Test Charges - Naturally move from low to high electric potentials

Example 8 A.What is the change in electric potential energy when a negative charge (-8.60  C) is moved from an electric potential of 0.0 v to an electric potential of 75.0 v? B.What is the change in electric potential energy when a positive charge (8.60  C) is moved from an electric potential of 0.0 v to an electric potential of 75.0 v?

Example 9 A.What is the change in electric potential energy if an electron is moved from a point with an electric potential of v to a point with an electric potential of v? B.How much work does it take to move this electron from an electric potential of v to v?