This preview shows pages 1–10. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Chapter 18 Electric Potential and Electric Energy Electric Potential Energy The electrostatic force is a conservative force It is possible to define an electrical potential energy function with this force Work done by a conservative force is equal to the negative of the change in potential energy Work and Potential Energy There is a uniform field between the two plates As the charge moves from A to B, work is done on it W = Fd=q E x (x f x i ) PE =  W =  q E x (x f x i ) only for a uniform field Potential Difference The potential difference between points A and B is defined as the change in the potential energy (final value minus initial value) of a charge q moved from A to B divided by the size of the charge V = V B V A = PE / q Potential difference is not the same as potential energy Potential Difference, cont. Another way to relate the energy and the potential difference: PE = q V Both electric potential energy and potential difference are scalar quantities Units of potential difference V = J/C A special case occurs when there is a uniform electric field V = V B V A = E x x Gives more information about units: N/C = V/m Energy and Charge Movements A positive charge gains electrical potential energy when it is moved in a direction opposite the electric field If a charge is released in the electric field, it experiences a force and accelerates, gaining kinetic energy As it gains kinetic energy, it loses an equal amount of electrical potential energy A negative charge loses electrical potential energy when it moves in the direction opposite the electric field Energy and Charge Movements, cont When the electric field is directed downward, point B is at a lower potential than point A A positive test charge that moves from A to B loses electric potential energy It will gain the same amount of kinetic energy as it loses in potential energy Summary of Positive Charge Movements and Energy When a positive charge is placed in an electric field It moves in the direction of the field It moves from a point of higher potential to a point of lower potential Its electrical potential energy decreases Its kinetic energy increases Summary of Negative Charge Movements and Energy When a negative charge is placed in an electric field It moves opposite to the direction of the field It moves from a point of lower potential to a point...
View Full
Document
 Spring '08
 GOMEZ
 Electric Potential, Energy, Force, Potential Energy, Work

Click to edit the document details