Magnetic Flux Density: B, \phi, H - True or False?

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Discussion Overview

The discussion revolves around the definitions and relationships between magnetic flux density (B), magnetic flux (\phi), and magnetic field strength (H). Participants explore the meanings of these terms and their usage in different contexts, leading to confusion and varying interpretations.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that magnetic flux density (B) is distinct from magnetic flux (\phi) and question why B is sometimes used interchangeably with magnetic flux.
  • It is proposed that magnetic flux density indicates the strength of a magnetic field, but there is uncertainty about this definition.
  • One participant suggests that magnetic field strength (H) is more relevant when discussing magnetic materials, while B is seen as a result of H.
  • Another participant clarifies that B represents magnetic flux per unit area, while \phi represents the total magnetic flux, drawing an analogy to density and volume.
  • There is a claim that magnetic field strength and magnetic flux density are not the same, with a proportional relationship involving permeability, but this is contested.
  • Participants note that terminology in magnetism can be ambiguous and recommend using B and H symbols to avoid confusion.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and relationships between B, \phi, and H, indicating that the discussion remains unresolved with multiple competing interpretations.

Contextual Notes

There are limitations in the definitions and relationships discussed, with some participants noting the ambiguity in terminology and the potential for varying interpretations over time.

unseensoul
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magnetic flux density is denoted by the B symbol
magnetic flux is denoted by the \phi symbol

so why do people use B as if they were referencing to magnetic flux?

"magnetic flux density is a measurable quantity indicating the strength of a field" ...this was stated by a teacher of mine...anyway, is true?

First, magnetic flux density isn't it the same as magnetic induction, i.e. magnetic flux per unit area perpendicular to the magnetic field?
Second, I thought that the strength of a field was denoted by H...

I've been searching throughout the internet and I found different meanings for the same thing which lead me to get more confused.

Best regards
-unseensoul
 
Physics news on Phys.org
Here's a good start
http://hyperphysics.phy-astr.gsu.edu/Hbase/hframe.html

Just remember that, at a practical level, the magnetic field strength H is most useful when dealing with magnetic materials (soft iron, silicon steel, etc.).

If you just want a memory trick (not completely true), think of H as the cause and B as the result.

I'm sorry to give a 75% answer (i.e., not absolutely true), but I can't think of anyway short of about three hours to say it all. Perhaps another responder will have a more succinct answer.
 
I've taken a look to it before I came here and it didn't help me :\

Thank you for your reply

ps: I'm sorry to get you back so late...
 
B is magnetic flux density - keyword: density. As in, magnetic flux per unit area/volume. Phi is the total amount, i.e. in the same way that density * volume = mass.

Referring it to as magnetic flux is probably just a short hand way of going about things.
 
I didn't mean that. What I'd like to know is why is the magnetic flux density referred as the magnetic field strength?

Thank you
 
Magnetic field strength is not the same as the magnetic flux density. They are proportional (the constant (?) of proportionality being permeability). If some source refers to them as the same, that source is incorrect.
 
The words describing magnetism can be ambiguous and vary over time.
It is best to use B and H instead of words, because the usages B and H are universal.
 

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