Two 10-cm-long thin glass rods uniformly charged to + 10\;{\rm nC} are placed side by side, 4.0 cm apart. What are the electric field strengths E_1, E_2, and E_3 at distances 1.0 cm, 2.0 cm, and 3.0 cm to the right of the rod on the left, along the line connecting the midpoints of the two rods?

Question

katiehamlet · Answer

What formula do I use for E_1 or E_3? I know the field is zero at E_2, but I need the formula for the electric field at the other points.