Two small insulating spheres with radius 5.00×10-2 m are separated by a large center-to-center distance of 0.450 m. One sphere is negatively charged, with net charge -1.85 nanoCoulombs , and the other sphere is positively charged, with net charge 3.15 nanocoulombs . The charge is uniformly distributed within the volume of each sphere.
What is the magnitude of the electric field midway between the spheres?