Chapter 2: Electric Field of Line Charges

Interactive 3

Assume that a line charge of density  (given in C/m) is stretched along the z-axis in a cylindrical coordinate system. The electric field vector at a point P is then given by

where ,  (in meters) is the -coordinate of P, and  is the respective unit vector. In more general terms,  is the distance from the line charge L to P. Remember that the distance from a point to a straight line L is measured along a piece of line, which is perpendicular to L.

Here, we illustrate the E-field due to line charges along the three major axes in a rectangular coordinate system. All three charges are of line charge density  (C/m). The observation point P is at (3,4,3). We assume that the units for distance are millimeters.

You can select the line charges, which you want to activate, by clicking in the respective window. You may activate one, two or all three line charges, and observe the superposition of all three field vectors.

 
Interactive Applet

Electric Field of Line Charges