Electric field lines are computed with the following algorithm: 1. Pick a starting point (x.y) in space. Compute the electric field vector direction there. 2. Take a small step along this vector to another point. Compute the electric field vector at this point. Connect the previous vector to this one. 3. Repeat 2. until you step off the page, step into a charge, or reach a location where the electric field is zero. 4. Repeat 1-3 until you have enough field lines to determine the field direction in a given region of the plot. 1. A point charge +q is at (x.y) = (-1,0) and a point charge +q is at (x,y) = (+1,0) meters. Draw an electric field line for each of the following starting points. %3D (x.y) = (-1.1,0) %3D (x.y) = (+1.1,0) (x.y) = (+0.9,0) (x.y) = (0,0.1) (x.y) = (0,-0.1) %3D %3D %3D Notice how our first choice of points was those for which drawing the electric field line was easy.

Electric field lines are computed with the following algorithm: 1. Pick a starting point (x.y) in space. Compute the electric field vector direction there. 2. Take a small step along this vector to another point. Compute the electric field vector at this point. Connect the previous vector to this one. 3. Repeat 2. until you step off the page, step into a charge, or reach a location where the electric field is zero. 4. Repeat 1-3 until you have enough field lines to determine the field direction in a given region of the plot. 1. A point charge +q is at (x.y) = (-1,0) and a point charge +q is at (x,y) = (+1,0) meters. Draw an electric field line for each of the following starting points. %3D (x.y) = (-1.1,0) %3D (x.y) = (+1.1,0) (x.y) = (+0.9,0) (x.y) = (0,0.1) (x.y) = (0,-0.1) %3D %3D %3D Notice how our first choice of points was those for which drawing the electric field line was easy.