# B Magnetic permeability...

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1. Sep 25, 2015

### Luminescent

Who is credited for deriving the value of magnetic permeabilty in a classical vacuum?
How would one go about sourcing information in relation to such a value?

2. Sep 25, 2015

### Hesch

μ0 = π * 4E-7. It's just a passed value, that is comfortable.

Say you have a long straight conductor carrying a current = 1 Adc.

In a distance, R = 1 m, you will find H = 1A / 2πR [ A/m ] = 1 / 2π [ A/m ].

To find the B-value, you multiply by μ0, so

B = 2E-7

which some people regarded as a comfortable value ?

Anyway the value π is not included in the value of B, and B "becomes close to" about 1T in practical applications ( a magnet you know where to buy ).

It's just like 1 meter = a long step.

3. Sep 26, 2015

### Luminescent

when using this value in a research paper who would I give credit to?

4. Sep 26, 2015

### Hesch

Well, mayby the members at some congress have voted as for the factor 4*10-7.

I think the factor π has just been accepted as ok.

The idea has just been to achieve a practical unit ( Tesla ) with a value about 1. ( for a "normal" magnet ).

Last edited: Sep 26, 2015
5. Sep 26, 2015

### Luminescent

µ0 = 4π×10−7 N / A2 ≈ 1.2566370614...×10−6 H / m or T·m / A or Wb / (A·m) or V·s / (A·m)

So when using any of the above values in a peer review research paper, I would give reference to electromagnetic theory and electromagnatism?

6. Sep 26, 2015

### Staff: Mentor

7. Sep 26, 2015

### Luminescent

8. Sep 26, 2015

### Vanadium 50

Staff Emeritus
If you had taken the advice PF had given you, you would be reading journals, and you would have all the citation examples you could use.

9. Sep 27, 2015

### Drakkith

Staff Emeritus
Thread closed.

Last edited by a moderator: Sep 27, 2015
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