---
# System prepended metadata

title: 額外小筆記

---

# 額外小筆記
### 讀書時間分配
* A category : 4(學分) hours + 8 hours = 12 hours / week
* B category : 3(學分) hours + 3 hours = 6 hours / week
* C category : 2(學分) hours + 0 hours = 0 hours / week 
# 普物筆記
### 靜電不平衡
***Maxwell Equations***
 ![](https://i.imgur.com/US4CfTg.png)
### Explanation of each equation
* equation 1 : 電荷會產生電場
* equation 2 : 沒有磁單極，也就是不像電荷一樣有磁荷
* equation 3 : 如果 magnetic field 會變動的話，就會產生 electric field (磁動生電)
* equation 4 : 電流會產生磁場(前半) / 電動生磁(後半)
### 符號的意義
*  ε0 => constant 
*  μ0 => constant
*  ε0*μ0*c^2
*  ρ => Charge density
*  J => Current density
*  E => Electric field
*  B => Magnetic field  
### If you consider elctric field and magnetic field constant in time ?
![](https://i.imgur.com/fRUJ8JK.png)
* 上面兩條的結論是(庫倫定律)
* 下面兩條的結論是(必歐-沙伐定律)
###### 所以若只把電磁學限制在這兩個特殊結論的範疇是不行的!!~
### 靜電不平衡
![](https://i.imgur.com/Q12yOFU.png)

![](https://i.imgur.com/R6ldh3V.png)

![](https://i.imgur.com/TFJVY0X.png)

###### 用反證法證明靜電不平衡
![](https://i.imgur.com/axftVYN.png)
