Need Help Understanding Electric Flux and Electric Flux Density

In summary, the conversation discusses the concept of flux and its application in computing the flow of a vector field on a surface. The equation for flux is defined as the dot product of the vector field and the surface, and its density requires the orientation of the surface. The difference between electric flux and electric flux density is also mentioned, with the latter being referred to as the electric displacement field. The conversation ends with a request for clarification and an image provided to confirm the previous statements.
  • #1
Shreya
188
65
Homework Statement
What is Electric Flux?
What is the difference between Electric Flux and electric flux density?
Relevant Equations
Electric Flux = E*ds cos (theta)
I don't understand the exact meaning of flux.
Please be kind to help.
 
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  • #2
Have you ever computed the flux of any vector field?
 
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  • #3
The relevant equation
[tex]\mathbf{E}\cdot\mathbf{dS}[/tex]
is a definition of flux or flow of vector field E on surface dS. It is interpreted as a quantity flow passing through surface ##\mathbf{dS}=\mathbf{n} dS##.
Its (surface) density is [tex]\frac{\mathbf{E}\cdot\mathbf{dS}}{dS}=\mathbf{E}\cdot\mathbf{n}[/tex]
which requires orientation of the surface.
 
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  • #4
Gordianus said:
Have you ever computed the flux of any vector field?
No, but I learned abt Volume flux as volume passing through an area per unit time
 
  • #5
anuttarasammyak said:
The relevant equation
[tex]\mathbf{E}\cdot\mathbf{dS}[/tex]
is a definition of flux or flow of vector field E on surface dS. It is interpreted as a quantity flow passing through surface ##\mathbf{dS}=\mathbf{n} dS##.
Its (surface) density is [tex]\frac{\mathbf{E}\cdot\mathbf{dS}}{dS}=\mathbf{E}\cdot\mathbf{n}[/tex]
which requires orientation of the surface.
Thanks a lot!
Can you please explain the difference between electric flux and electric flux density?
Is electric flux density = electric field ?
Please help
 
  • #6
Shreya said:
Is electric flux density = electric field ?
The last line of post #3 is electric flux density for given infinite area ##\mathbf{dS}##.

Electric displacement field ##\mathbf{D}## is (was ?) called electric flux density but is something different from the above mathematics. Along the same discussion I wonder magnetic flux density is proper as one of the names of ##\mathbf{B}##. I should appreciate the advice of senior learners.
 
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  • #7
Got this image from a source: I think it confirms what anuttarasammyk has said, Thank
You!
 

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1. What is electric flux?

Electric flux is a measure of the electric field passing through a given surface. It is defined as the dot product of the electric field and the normal vector of the surface.

2. How is electric flux calculated?

Electric flux is calculated by taking the dot product of the electric field and the normal vector of the surface. This can be represented mathematically as Φ = E · A, where Φ is the electric flux, E is the electric field, and A is the area of the surface.

3. What is the unit of electric flux?

The unit of electric flux is volt meters squared (V·m²) in SI units. In other unit systems, it can also be expressed as newton meters squared per coulomb (N·m²/C) or tesla meters squared (T·m²).

4. What is electric flux density?

Electric flux density, also known as electric displacement, is a measure of the amount of electric flux passing through a given surface per unit area. It is represented by the symbol D and has the unit coulombs per square meter (C/m²) in SI units.

5. How is electric flux density related to electric flux?

Electric flux density is related to electric flux through the equation D = εE, where ε is the permittivity of the medium and E is the electric field. This means that the electric flux density is directly proportional to the electric field, and the constant of proportionality is the permittivity of the medium.

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