Charges and electric field - Uni Siegen · 2018. 12. 13. · (Gauss' law with dielectric). q', q E.dA q, Gaussian surface (b) Gaussian surface (a) The initial electric field inside

Charges and electric field

Coulomb´s law

charges

Electric field

Electric field of a dipole

Dipole moment

Elementary charge

Probe the field by a „test“ charge q

Gauss law

flux

Electrical flux

Gauss law and Coulomb law

E-Field of a conducting plate

Electrical potential

Applied work Wappl = q DV

Equipotential surfaces

Defined by DV=0,No work is done on a equipotential plane

Calculating potential in an electric field

Potential due to a point charge

A system of point charges

Calculating E from V

Capacity calculation

Parallel and Series connection of capacities

Energy stored in electric field

Dielectric constants

Dielectrics

Current and current density

i = dq/dt

1 Ampere = 1 A = 1 coulomb per second

i= i1 + i2

Resistance and resistivity

R = V/I Ohm´s law

1 Ohm = 1 W = 1 volt per ampere

r = E/J [Wm]

s = 1/r [1/Wm]

R= r L/A

J= s E

Power in Electric Circuits

Using Ohm´s law

Electrical circuits

EMF = electromotive force

Single loop circuit

Potential loop of a circuits

Multiloop circuits

i1 + i3 = i2

Substitute : i3R3

example

RC - circuits

t= RC