ch18_pm

 = = == CHAPTER 18 ==

 =Section 1 =

**A uniform electric field is a field where all of the lines are parallel and equidistant to each other. When there is an electric field caused by a very distant carge, it is uniform over a smal area considering the field lines are near parallel and the difference in field strentgh is neglible over a small dastance. A uniform electric field will always exer a constant force on an object that is charged. If said object is displaced, work will need to be done and energy accumulated to create a force to move it.** Electric Potential Energy can be determine by taking the product of the force by the field and its position in said field. Mathematically, in a uniform electric field with a strength of E with a displacement d measured in the direction of E. math \displaystyle PE_{electric}=-qEd math The negative sign is required because the displacement of a positive charge to increase the potential energy should come from the opposite direction of the the field. If the initial and final positions are taken before and after a displacement, the change in potential energy can be found thusly. math \displaystyle\Delta PE_{electric}=-qE\Delta d math

=Section 2= Electric potential(V) is defined as the electric potential energy per unit charge math \displaystyle V=\frac{\Delta PE_{electric}}{q}=-Ed math or math \displaystyle V=-Ed math The relative difference in electrical potential between two points is the potential difference. It is measured in the same way as electric potential, which is in J/C. [[math]] \displaystyle\Delta V=\frac{\Delta PE_{electric}}{q} [[math]] The electric potential at a given point is independent of the charge at that point. The only truly useful part is the electric potential between the two given point.