Understanding the Science Behind Farad and Its Applications

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Discussion Overview

The discussion revolves around the concepts of capacitance, specifically the unit Farad, and its relationship to other physical quantities such as electric permittivity and magnetic permeability. Participants explore the definitions, units, and implications of these concepts in the context of electromagnetism.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant presents equations relating the speed of light, electric permittivity (e0), and magnetic permeability (m0), questioning the coherence of these relationships.
  • Another participant seeks clarification on the definitions of units used in the equations, particularly questioning the meaning of "m" and "F" in the context of e0.
  • A participant explains that a Farad is a unit of capacitance, describing its relationship to charge and voltage in a capacitor.
  • One participant expresses uncertainty about the definitions of e0 and m0, citing sources that provide different units than initially stated.
  • Another participant emphasizes the importance of understanding the fundamental units of a Henry and a Farad, providing their definitions in terms of other physical quantities.
  • A participant reflects on the historical context of the units, mentioning Joseph Henry's contributions to electromagnetism and his competition with Faraday.
  • One participant humorously comments on the confusion caused by the terminology and units, likening it to a semantic struggle.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and relationships of the units discussed, with some seeking clarification and others asserting their interpretations. The discussion remains unresolved regarding the accuracy of the initial claims about the units and their relationships.

Contextual Notes

There are limitations in the clarity of definitions and the assumptions underlying the equations presented. Some participants express uncertainty about the correctness of the information in the referenced texts.

deda
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This ain't no theory development but scientific facts[/color]

In "Special theory of relativity" by dr. V.Z. Belgrade 1997 it's writen:
[tex]c=\frac{1}{\sqrt{e_0m_0}}=3E8\frac{m}{s}[/tex] for the speed of the light;

In "Electro-magnetics 1" by dr. Lj.J. Skopje 1994 it's writen:
[tex]e_0=\frac{1E-9}{36 \pi} \frac{F}{m}[/tex] for dielectric const of vacuum;

[tex]m_0=4 \pi 1E-7 \frac{F}{m}[/tex] for magnetic permeability in vacuum;

=> [tex]c=3E8 \frac{m}{F}[/tex] and 1F=1s;

[tex]F_C=\frac{-kQ_1Q_2}{R^2}[/tex] - The Coulomb's law;

[tex]k=9E9\frac{Nm^2}{C^2}=\frac{1}{4\pi e_0}[/tex] for Coulomb's proportionale;

=> [tex]e_0=\frac{1E-9}{36 \pi} \frac{C^2}{Nm^2}[/tex];

=> [tex]\frac{C^2}{Nm^2}=\frac{F}{m}[/tex];

=> [tex]\frac{C^2}{Nm}=F[/tex];

=> [tex]Nms=C^2=\frac{kgm^2}{s}[/tex];

=> [tex]kgm^2=C^2s[/tex];

My question is where is the sense in that?[/color]
 
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I wish that you show me where I'm wrong.
But if I'm not...
 
First, you didn't say that or ask any question in your first post.

Second, it might help it you clarified this.

For example, in [tex]e_0=\frac{1E-9}{36 \pi} \frac{F}{m}[/tex], what are m and F? I might be inclined to think that "m" is mass but this is supposed to be the "dielectric const of vacuum".
 
sorry

these are units:
F is Farad;
m is meter;
kg is kilogram;
s is second;
C is Coulomb;
N is Newton;
 
If you took a non-leaky discharged capacitor and charged it for one Second at a current of one Amp and at the end of the charge period measured the voltage across the capacitor and found it to be exactly one Volt, then that capacitor would have a capacitance of one Farad.

Explanation:

A Farad is a unit of measure for capacitors.

Capacitors are a bit like tiny rechargeable batteries.

A capacitor with a capacitance of one Farad would store one Coulomb of charge when charged to a voltage of one volt.

One Coulomb of charge is the amount of charge delivered, when one Amp flows for one second.
 
I'm sure I read my book corectly but,
I made some search on e0 and m0.
Here is what I found:
-http://www.calculator.org/properties/electrical_permittivity.prop this one is actually in F/m (as I said)
-http://www.calculator.org/properties/magnetic_permeability.prop and this in H/m (not as I said)

So, I guess I should also aks how much is one henry too.
Make it easy for me.Tell me right away how much is
squareroot(henry times farad).
 
The question you need to ask is, not "how much it 1 Henry" but What are the fundamental units of a Henry.

Ok, now that you have asked the rigth question

H => Volt second/Amp

Farad => Amp Second/Volt
 
There was definitely error in the book "Electromagnetics 1" that I recalled. I'm positive that's how it's written there. I know that profesor. I might warn him some time.

This topic is history.
 
gahh I am awash in a sea of units, the word Henry itself reminds me more of the King Henry's in England rather than the electric induction unit that holds its scientific name. Or it could be the orator Patrick Henry from the House of Burgesses, "Give me liberty or give me death!" Semantics playing a game with my head, and I am losing.
 
  • #10
It was Joseph Henry, an American physicist who was (more or less) in competition with Faraday in the electromagnetism search and did fine work. He discovered reverse induction (magnetic field producing current) independently of Faraday.
 
  • #11
this could get massy but i don't seem to mind

henry times farad = anna times jesica

blew!
 

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