Electric Potential AP Physics Chapter 17

Electric Charge and Electric Field 17.1 Electric Potential Energy and Potential Difference

Electric Potential Energy & Potential Difference Electricity can be viewed in terms of energy The electrostatic force is conservative because it depends on displacement Now We can calculate this value for a uniform electric field 17.1

Electric Potential Energy & Potential Difference Positive test charge – increases when moved against the field Negative test charge – increases when moved with the field Electric Potential (Potential) – electric potential energy per unit charge 17.1

Electric Potential Energy & Potential Difference Only difference in potential are meaningful Potential Difference (Electric Potential Difference) – is measureable Measured in volts (after Alessandro Volta) 17.1

Electric Potential Energy & Potential Difference If we want a specific potential value at a point, we must pick a zero point. That point is usually either A. The ground B. At an infinite distance 17.1

Electric Charge and Electric Field 17.2 Relation between Electric Potential and Electric Field

Relation between Electric Potential & Electric Field Work It also is So pew 17.2

Electric Charge and Electric Field 17.3 Equipotential Lines

Equipotential Lines Equipotential Line or Equipotential Surface – one at which all points are at the same potential 17.3

Equipotential Lines Must be perpendicular to the electric field Constant Field 17.3

Equipotential Lines Must be perpendicular to the electric field Point Charge 17.3

Equipotential Lines Must be perpendicular to the electric field Dipole 17.3

Electric Charge and Electric Field 17.4 The Electron Volt, a Unit of Energy

The Electron Volt A unit of energy – for electrons, atoms, or molecules Electron Volt (eV) 17.4

Electric Charge and Electric Field 17.5 Electric Potential Due to Point Charge

Electric Potential Due to Point Charge Using calculus it can be shown that the electric potential a distance r from a single point charge q is Assuming that potential is zero at infinity 17.5

Electric Charge and Electric Field 17.7 Capacitance

Capacitance Capacitor – device that stores electric charge In RAM, Camera Flash, 17.7

Capacitance Simple capacitors consist of two plate The symbol for a capacitor is The symbol for a cell is The symbol for a battery is 17.7

Capacitance When a potential difference is placed across a capacitor it becomes charged This process takes a short amount of time The charge on each plate is the same, but opposite charge The amount of charge is proportional to the potential difference A constant C (Capacitance) gives 17.7 Charging a Capacitor Time for RC Circuit

Capacitance Capacitance – Unit Farad For a parallel plate capacitor, the capacitance depends on the area of the plates, the distance between the plates 17.7

Electric Charge and Electric Field 17.8 Dielectrics

Dielectrics Most capacitors have an insulator between the plates Called a Dielectric Increases the capacitance by a factor K Called the dielectric constant 17.8

Dielectrics Some Dielectric Constants 17.8 MaterialK Paper3.7 Glass5 Rubber6.7 Mica7 Strontium Titanate 300

Electric Charge and Electric Field 17.9 Storage of Electric Energy

Storage of Electric Energy A charged capacitor stores energy 17.9