A −2.0 nC charge and a +2.0 nC charge are located on the x-axis at x=−1.0 cm and x=+1.0 cm, respectively.

a. Other than at infinity, is there a position or positions on the x-axis where the electric field is zero? If so, where?
b. Other than at infinity, at what position or positions on the x-axis is the electric potential zero? Sketch graphs of the electric field strength and the electric potential along the x-axis.