Electrostatics 2 Flashcards
Electric flux=
The density of electric field lines through an area A
Φ=
2 equations
=EAcos(pheta)
=q/ε0 (this is gauss law)
Consequences of gauss law
Electrostatic field inside an isolated conductors is zero
Cavities inside conductors are shielded
If we add charge to a hollow conductor in an electric field
Charge will move to the outer surface.
Then we can define a Gaussian surface which encloses q=0, E=0, Φ=0
Conservative field=
Work done is independent of path. Work done along a closed path is zero
Electric potential=
Work required to place a unit charge at a point
C= (2equations)
C=q/V
C=(ε0A)/d
4 purposes of a dielectric
Maintains mechanical separation between plates
Provides electrical insulation
Allows capacitor to hold a higher charge
Increases capacitance
Dielectric constant equations (3)
E=Eair/ k
ε=k ε0
C=k(ε0A/d)
Dielectric materials have molecules that have a … or can be induced to have one by an… the resulting fields from the …. tend to
Have a permanent electric dipole momentOr can be induced to have one by an external electric field. The aligned electric dipole moments partially cancel the original field
Dielectric strength =
The ability of the material to withstand potential difference
What happens when the electric field strength is greater than the dielectric strength
Dielectric breaks down and starts conducting charge between plates via a spark
