電磁學平時考2

(15%)1. What is the mathematical define of the divergence of A?

(15%)2. What is the divergence theorem?

(10%)3. A 2C point charge is located at the origin , and a second point charge of 4C is  located on the x axis at the poison(30

,0)cm. How much work is required to bring a 10C point charge from infinity to the point(0 ,40)cm.

(20%)4 What is the define of Gauss law in free space？

(20%)5.What is the definition of electric  dipole moment?

(20%)6.請寫出靜電學在真空中的假設。