Difference between Electric flux density,electric field strength.....

sachin123

I want to know the difference between,electric flux density and electric field strength.Are they the same?
And also,there is a magnetic field(measured in Tesla),magnetic flux(in Weber),magnetic flux density(Weber per m²),magnetic field strength(measured in Tesla again?).
I am finding these very confusing.Can someone clear this out?
Thanks

tiny-tim

hi sachin123!

from the pf library on flux …

In electromagnetism, flux always means total flow through a surface (a scalar), and is measured in webers (magnetic flux) or volt-metres (electric flux).

Flux is the amount of a vector field going through a surface: it is the integral (over the surface) of the normal component of the field

flux density (btw, this is density per area, not per volume) is the same as the field …

flux = ∫ field "dot" area, so field = flux per area = flux density …

tesla = weber/metre²

(and "strength" just means "amount" …

you can leave it out when writing, and ignore it when reading )

sachin123

I am clear with Electric field strength(=electric flux density) and electric flux.

1.)Does it mean that magnetic field strength=magnetic flux density?

and...
from what you said,
magnetic field strength = magnetic field.


But,here is what my book says:
Magnetic field strength (H)=B/[tex]\mu[/tex]
where B is magnetic flux density.
Now weren't they supposed to be the same?(magnetic flux density and Magnetic field strength)

tiny-tim

ah, i see …

your book is calling H (in amps per metre) the magnetic field strength …

i haven't come across that before …

i've seen magnetic field intensity for H, but not strength

oh, in that case forget what i said about ignoring the word "strength": clearly some books are using it to distinguish H from B (in webers per metre squared)

(but the best way to distinguish them is to call them the H-field and the B-field )

sachin123

So,to conclude it,

magnetic flux is number of magnetic lines passing through surface area.......
unit:weber

magnetic flux density is number of magnetic lines passing through unit surface area.......
unit:weber per (m square)

magnetic field is same as magnetic flux density

magnetic field strength =magnetic field intensity is H =B/(mu)
unit:A per m

Is it correct?

sachin123

'mu' i meant as [tex]\mu[/tex]