Calculate the magnitude of the electric field at the origin due to the following distribution of charges: +q at (x,y) = (a,a), +q at (a,-a), -q at (-a,-a) and -q at (-a,a). Where q = 8.10 x 10-7 C and a = 3.50 cm.
Set up an 8-point compass at the origin, where north points along the positive y-axis, such as that shown in the diagram to the right. What is the direction of the electric field at the origin created by the charge distribution given in the previous part?