If we take the Vector quantity E which is the electric field strength (a vector as it has both magnitude and direction) and multiply it by the permittivity ε, we get a new vector D.
So D = εE = ε * Q/4π ε r2 , the ε cancles out leaving us with D = Q/4π r2
Notice how the electric flux density is independant of the permittivity ε. What does this mean?
Well say we had an electric field acting on a type of material, then from the formula for the electric field strength we know that the value of E is dependant upon the material used by the value of the permittivity ε. But the electric flux density D will remain the same no matter what material you use.
Basically although changing the types of materials will effect the electric field strength E, it will not affect the electric flux density D.
So D = εE = ε * Q/4π ε r2 , the ε cancles out leaving us with D = Q/4π r2
Notice how the electric flux density is independant of the permittivity ε. What does this mean?
Well say we had an electric field acting on a type of material, then from the formula for the electric field strength we know that the value of E is dependant upon the material used by the value of the permittivity ε. But the electric flux density D will remain the same no matter what material you use.
Basically although changing the types of materials will effect the electric field strength E, it will not affect the electric flux density D.
No comments:
Post a Comment