Electrical potential, V, like the electric field, is created what and tools

source charges. - potential of a point charge, Vpoint= 1/4pieeo x q/r - principle of superposition

For multiple point charges

Use superposition V= V1+V2+V3+...

For a continuous distribution of charge steps

1)Model as a simple charge distribution 2) Draw picture - Coor system -Identify point of potential in interest 3) Solve by setting up sum equation V= sum n and i=1 = Vi - Divide charge into point- like delta Q - Find potential due to delta Q -Use charge density to replace delta Q with an integration coor, then sum n= Q/A A=> rod=>pieR^2 A=>disk=> L x w= 2pier^2 x deltar V is easier than Efield as its a scalar

If charge q is placed in an electrical potential. the systems electrical potential energy is

As an interaction energy, Uelec=qV

Electrical potential energy of 2-point charges is

Uq1+q2= Kq1q2/r = 1/4pieeo x q1q2/r

Potential energy of two opposite charges

negative

Potential energy in an electric field of an electric dipole with the dipole moment p is

Uelec= -pEcos delta= -p vector x Efield vector

Solving conservation of energy problems

1) Model as an isolates system 2) Draw before and after representations 3)Solve for mechanical energy as its conserved with Kf+Uf=KiUi where k is the sum of kinetic energies due of all particles and V is potiential due to source charges

Direction of Voltage in a parallel- plate capacitor

Lower to higher potential, - to + where it is V= Es; s= distance from negative plate so Efield is E= deltaVc/d