diff --git a/education/physics/PHYS2220/Electric Charge.md b/education/physics/PHYS2220/Electric Charge.md index 845b80e..49019fc 100644 --- a/education/physics/PHYS2220/Electric Charge.md +++ b/education/physics/PHYS2220/Electric Charge.md @@ -6,11 +6,14 @@ - The smallest discrete quantity of charge is $\frac{1}{3}e$. - In an isolated system, the net charge will always remain constant. -# Electric Force +# Coulomb's Law - Two charges will exert a force on each other along the line joining them. - The magnitude of this force is proportional to the *product of the charges* and inversely proportional to the to the $\sqrt{dist}$. - The equation to determine the force between two charges is as follows: - $$ \vec{F_{12} = \vec{r}k\frac{q_1q_2}{r^2}} $$ + $$ \vec{F}_{12} = \vec{r}k\frac{q_1q_2}{r^2} $$ - $\vec{r}$ is a unit vector pointing from charge 1 to charge 2 - - $k$ is Couloumb's constant, or $8.99 * 10^9 \frac{Nm^2}{C^2}$ - - $q_1$ and $q_2$ \ No newline at end of file + - $k$ is Coulomb's constant, or $8.99 * 10^9 \frac{Nm^2}{C^2}$ + - $q_1$ and $q_2$ are the charges + - $r$ is the distance between those charges + - The resulting force will push away if $q_1q_2$ is *positive*, and attract if $q_1q_2$ is negative. This is where the rule "opposites attract, like repels" comes from +- Coulomb's law only holds exactly true for *point charges* i.e a proton \ No newline at end of file