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Jan29-13, 07:15 PM
P: 39
i have read the articles where the flux (either in case of electric flux or magnetic )is described as the no of lines passing through a surface area ( open in case of magnetic characterized by boundary and closed in case of electric flux density) or considered as an component of electric field or mag. field through that surface..
below is exact context:-
The magnetic flux through some surface, in this simplified picture, is proportional to the number of field lines passing through that surface (in some contexts, the flux may be defined to be precisely the number of field lines passing through that surface; although technically misleading, this distinction is not important). Note that the magnetic flux is the net number of field lines passing through that surface; that is, the number passing through in one direction minus the number passing through in the other direction (see below for deciding in which direction the field lines carry a positive sign and in which they carry a negative sign). In more advanced physics, the field line analogy is dropped and the magnetic flux is properly defined as the component of the magnetic field passing through a surface
but rather my textbook defines that it is convenient to replace sometimes the magnetic or electric field lines with flux lines..!!
FLUX LINES...: if its a scalar then how could we associate lines with it i mean we are here concerned with no of lines which is absolutely a scalar..
and further there was a post here about differences bet flux and flux density
and it was made clear that:-
Magnetic flux, Φ, is a scalar, measured in webers (or volt-seconds), and is a total amount measured across a surface (ie, you don't have flux at a point).

Magnetic flux density, B, is a vector, measured in webers per square metre (or teslas), and exists at each point.

The flux across a surface S is the integral of the magnetic flux density over that surface:
Φ = ∫∫S B.dS
(and is zero for a closed surface)

Magnetic flux density is what physicists more commonly call the magnetic field.

It is a density per area, rather than the usual density per volume.
what i am here concerned about is that magnetic flux density is commonly called as mag field but if its so then why do we have the relation D=εE
where D is flux density and E is the electric field ..!!
further my textbook (sorry i can't show the diagram) gives that convention of magnetic flux lines across the n conductors and i can barely see the difference bet flux and field lines..
and to further confuse there is a point in case of parallel capacitors that aD=q
or area times flux density=charge ( the reason it is because it is parallel plates..)
this is all really confusing me a lot sometimes it says it is a scalar but at same time it gives me flux lines and also sometimes give me a hint that flux density and field intensity are same but then there exists a relation bet two..
what it is.....??
PS: and yes the textbook i have mentioned here is : network analysis by M.E VANVALKENBURG..!!
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