Coulomb's law: Difference between revisions
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'''A Mathematical Model''' | '''A Mathematical Model''' | ||
According to [1], <math>\vec{F}_{on1} = {\frac{q_{1}q_{2}}{4\pi\epsilon_{0}|\vec{r}_{12}|^2}}\hat{r}_{12}</math>. <math>\epsilon_{0}</math>, the electric permittivity of free space, has a value of <math>\epsilon_{0} = 8.8541878128\times10^-12 frac{farads}{meter}</math> according to [2]. <math>frac{1}{4\pi\epsilon_{0}}</math> can be conveniently approximated as <math>9\times10^9</math>, as is done in [1]. Thus Coloumb's Law is sometimes written as <math>\vec{F}_{on1} = {\frac{kq_{1}q_{2}}{|\vec{r}_{12}|^2}}\hat{r}_{12}</math>, where <math>k = 9\times10^9</math>. Moreover, if we define the ''electric field'' <math>\vec{E}</math> as the force felt per unit charge as a result of Coloumb's Law, then we can write Coloumb's Law as <math>\vec{E} = \frac{q}{4\pi\epsilon_{0}|\vec{r}|^2}\hat{r}</math>, where <math>\ | According to [1], <math>\vec{F}_{on1} = {\frac{q_{1}q_{2}}{4\pi\epsilon_{0}|\vec{r}_{12}|^2}}\hat{r}_{12}</math>. <math>\epsilon_{0}</math>, the electric permittivity of free space, has a value of <math>\epsilon_{0} = 8.8541878128\times10^-12 frac{farads}{meter}</math> according to [2]. <math>frac{1}{4\pi\epsilon_{0}}</math> can be conveniently approximated as <math>9\times10^9</math>, as is done in [1]. Thus Coloumb's Law is sometimes written as <math>\vec{F}_{on1} = {\frac{kq_{1}q_{2}}{|\vec{r}_{12}|^2}}\hat{r}_{12}</math>, where <math>k = 9\times10^9</math>. Moreover, if we define the ''electric field'' <math>\vec{E}</math> as the force felt per unit charge as a result of Coloumb's Law, then we can write Coloumb's Law as <math>\vec{E} = \frac{q}{4\pi\epsilon_{0}|\vec{r}|^2}\hat{r}</math>, where <math>\vec{r}</math> is the vector distance between the charge and the point in space at which the electric field is being measured. Therefore if we have many charges <math>q_{1},...,q_{j}</math>, we can write Coloumb's Law as <math>\vec{E} = \[ \sum_{n=0}^{j} {\frac{q_{n}}{4\pi\epsilon_{0}|\vec{r}_{n}|^2}}\hat{r}_{n} \]</math> | ||
'''A Computational Model''' | '''A Computational Model''' |
Revision as of 02:07, 29 November 2023
Claimed by Spencer Boebel (Fall 2023)
Coulomb's Law
Overview
Coulomb's Law states that [math]\displaystyle{ \vec{F}_{on1} = {\frac{q_{1}q_{2}}{4\pi\epsilon_{0}|\vec{r}_{12}|^2}}\hat{r}_{12} }[/math] , where [math]\displaystyle{ \vec{F}_{on1} }[/math] is the force on charge [math]\displaystyle{ q_{1} }[/math] by charge [math]\displaystyle{ q_{2} }[/math], [math]\displaystyle{ |\vec{r}_12| }[/math] is the distance between the charges, and [math]\displaystyle{ \hat{r}_{12} }[/math] is the unit vector pointing from [math]\displaystyle{ q_{1} }[/math] to [math]\displaystyle{ q_{2} }[/math]. [math]\displaystyle{ \epsilon_{0} }[/math] is the electric permittivity of free space. In words, it says that the force on one charged particle ([math]\displaystyle{ A }[/math]) by another charged particle ([math]\displaystyle{ B }[/math]) is directed at [math]\displaystyle{ A }[/math], is jointly proportional to the charges themselves (signs included), and is inversely proportional to the distance between [math]\displaystyle{ A }[/math] and [math]\displaystyle{ B }[/math] squared. Coloumb's Law holds only when the two particles are at rest, and it can be derived from Gauss's law, which is one of Maxwell's Equations. Coloumb's Law can be used to analyze electrostatic situations such as the movement of a charge suspended between two plates as well as determining the electric field from a given charge distribution.
Main Idea
A Mathematical Model
According to [1], [math]\displaystyle{ \vec{F}_{on1} = {\frac{q_{1}q_{2}}{4\pi\epsilon_{0}|\vec{r}_{12}|^2}}\hat{r}_{12} }[/math]. [math]\displaystyle{ \epsilon_{0} }[/math], the electric permittivity of free space, has a value of [math]\displaystyle{ \epsilon_{0} = 8.8541878128\times10^-12 frac{farads}{meter} }[/math] according to [2]. [math]\displaystyle{ frac{1}{4\pi\epsilon_{0}} }[/math] can be conveniently approximated as [math]\displaystyle{ 9\times10^9 }[/math], as is done in [1]. Thus Coloumb's Law is sometimes written as [math]\displaystyle{ \vec{F}_{on1} = {\frac{kq_{1}q_{2}}{|\vec{r}_{12}|^2}}\hat{r}_{12} }[/math], where [math]\displaystyle{ k = 9\times10^9 }[/math]. Moreover, if we define the electric field [math]\displaystyle{ \vec{E} }[/math] as the force felt per unit charge as a result of Coloumb's Law, then we can write Coloumb's Law as [math]\displaystyle{ \vec{E} = \frac{q}{4\pi\epsilon_{0}|\vec{r}|^2}\hat{r} }[/math], where [math]\displaystyle{ \vec{r} }[/math] is the vector distance between the charge and the point in space at which the electric field is being measured. Therefore if we have many charges [math]\displaystyle{ q_{1},...,q_{j} }[/math], we can write Coloumb's Law as [math]\displaystyle{ \vec{E} = \[ \sum_{n=0}^{j} {\frac{q_{n}}{4\pi\epsilon_{0}|\vec{r}_{n}|^2}}\hat{r}_{n} \] }[/math]
A Computational Model
Example
Connectedness
History
Coulomb's Law was first formulated in
See Also
-Biot-Savart Law -Law of Superposition -Gauss' Law
References
1. https://www.feynmanlectures.caltech.edu/II_04.html 2. https://physics.nist.gov/cgi-bin/cuu/Value?ep0