What is the magnitude of a the vertical electric field that will balance the weight of a plastic sphere of mass 3.0 grams that has been charged to -6.0 nC? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2) a. 4.9 x 10^6 N/C b. 7.8 x 10^5 N/C c. 6.9 x 10^6 N/C d. 2.1 x 10^6 N/C This problem has been solved!