vault backup: 2026-01-06 08:27:37

education/physics/PHYS2220/Electric Charge.md

@@ -35,3 +35,6 @@ It's largely impossible to sum the electric field from every particle in a piece
 	-  If the charge distribution extends throughout a *3d volume*, we describe it in terms of the **volume charge density** $\rho$, with units of $\frac{C}{m^3}$. 
 	- For charge distributions spread over *surfaces*, we use **surface charge density** $\sigma$ ($\frac{C}{m^2}$).
 	- For charge distributions spread over *lines*, we use **line charge density** $\lambda$ ($\frac{C}{m}$).
+- To find the point charge, we can use this formula:
+$$ \vec{E} = \int d \vec{E} = \int \frac{kdq}{r^2}\hat{r}$$
+-