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Swapnil
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Why is D called the "electric flux density vector"?
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Swapnil said:Thanks guys. Now I know.
BTW, is there something wrong with calling D the "electric field strength" (just like we call H the "magnetic field strength")?
More on whether to call H or B the magnetic field:marcusl said:.. because E and B are the fundamental field quantities, while D and H are derived [Jackson] "as a matter of convenience to take into account in an average way the contributions ... of atomic charges and currents." That is why E and B should be called fields, and why Mel Schwartz doesn't bother to even name H in his book. Furthermore, D is almost universally called Electric Displacement, and only rarely "dielectric flux density."
A survey of E&M books on my shelf shows B is called
Magnetic Induction -- by Smythe, Stratton, Jackson, Reitz & Milford
Magnetic Field -- Schwartz, Weber
alternately
Magnetic Flux Density -- Weber, Jackson
H is called
Magnetic Field or Field Intensity -- Smythe, Stratton, Jackson
Magnetic Intensity -- Weber, Reitz & Milford
unnamed -- Schwartz
Swapnil said:Wow! I didn't know that such a simple question would have such an interesting answer!
BTW, robphy the way you describe E, H, B, & D as geometric objects with "one/two-form;" what branch of mathematics would you need to study in order to become familiar with these types of terminologies?
robphy said:tensor calculus and differential geometry.
consult the references I linked in my previous post
Your units for D and B are for flux densities.ObsessiveMathsFreak said:E and H are fields. (V/m, A/m)
D and B are fluxes. (C/m^2, Wb/m^2)
You might do better with "Classical Electromagnetism" by Franklin which answers your question in chapter 6.shungmunga said:So my question is what is the physical meaning of vectors P, M, D and H? Also, what is the point of the permittivity number if it just cancels with that in the denominator of Coulomb’s constant when multiplying it with E? Someone please help show me where I’m going wrong.
Electric flux density vector, denoted by D, is a fundamental concept in electromagnetism that describes the amount of electric flux passing through a given surface per unit area. It is a vector quantity that takes into account both the magnitude and direction of the electric field.
The electric flux density vector is directly proportional to the electric field, with the constant of proportionality being the permittivity of the medium. This means that as the electric field increases or decreases, the electric flux density vector will also increase or decrease accordingly.
The SI unit of electric flux density vector is coulombs per square meter (C/m^2). This unit can also be written as farads per meter (F/m), as the permittivity of a vacuum is equal to 1 farad per meter.
Electric flux density vector and electric flux are related concepts, but they are not the same. Electric flux is a scalar quantity that measures the total amount of electric field passing through a given surface, while electric flux density vector is a vector quantity that describes the electric field at a specific point in space.
Electric flux density vector is used in various fields, such as electrical engineering, telecommunications, and physics. It is crucial for understanding the behavior of electric fields and designing devices such as capacitors, antennas, and transmission lines. It also plays a role in determining the dielectric strength of materials and analyzing electromagnetic radiation.