EMT: 2nd week part 3 Electric Field Intensity of a infinite line of charges

Hey there~

Since we already learn about finite line of charge, we ought to learn about infinite line of charges too.

Unlike finite line of charges, infinite line of charges is much easier to solve.

The equation only apply if the infinite line of charge is along the z-axis, if not then r is the perpendicular distance from the line to the point of interest.

Example:

Infinite uniform line charges of 5 nC/m lie along the x and y axes in free space. Find the electric field intensity at: (a) P_A(0, 0, 5); (b) P_B(0, 3, 4).

Solution:

(a)

(b)

I think the solution is pretty straight forward. I don't think any explanation is needed here. But just like what it stated, if the point is not along z-axis, we have to find the r which the line is perpendicular to the infinite line of charges.

Regards,

Daniel.