Problem 8. (Finding the zero points) A 3.0 nC charge is at ? =0 cm and a-1.0nC charge is at ? = 4 cm . At what point between the two charges on the x-axis is the electric potential zero? Express your answer in cm. Problem 9. (Relating field and energy) 50 pJ of energy is stored in an $ cm region of uniform electric field. What is the magnitude of the electric field? Express your answer in =. Problem 10. (Two long molecules) Two long molecules have unbalanced charges at the ends. The molecules are oriented so that the corresponding charges are opposite across each axis, as shown in the figure, with both centered along the x-axis and equidistant from the y-axis. A. Which of the following statements is true for the electric potential (?) along the y-axis? a. ? is positive for every point on the y-axis. b. ? is negative for every point on the y-axis. . ? is zero for every point on the y-axis. d. The sign will depend on where you are along the y-axis