Question

物理电磁题 求解答 c 问

The thin plastic rod of length L = 10.0 cm has a nonuniform linear charge density
λ = cx, where c = 49.9 pC/m. (a) With V = 0 at infinity, find the electric potential at point P2 on the y axis, a distance y = D = 3.56 cm. (b) Find the electric field component Ey at P2. (c) Why cannot the field component Ex at P2 be found using the result of (a)?

Answer 1

：：：

p2在哪里？？？？

先求 在 L上 取小段 dx  对p点的电场：E(r)

Ey=E(r)*sin(a)，，，其中：a为 E方向 与x轴的夹角，，

Ey=E（r）*D/r；

E(r)=K*q/r^2=k*c*dx/r.^2

有：：

Ey=k*c*dx/r^3=k*c*dx/(x^2+D^2)^(3/2);;

在对L 积分，，有：

Ey=k*c*积分（dx/（x^2+D^2）^(3/2)）;;积分范围：【-x；L-x】；；；；；

若 p点 在中点  就没有Ex的分量了  ；抵消了。。

希望 能看得清楚！！！

Answer 2

no picture

Answer 3

楼主这是考英语还是考物理啊