Para encontrarmos as magnetudes de campo elétrico, realizaremos os cálculos abaixo:

\(\begin{align} & a) \\ & E=\frac{kQ}{{{({{x}^{2}}+{{R}^{2}})}^{3/2}}} \\ & E=\frac{9\cdot {{10}^{9}}\cdot {{10}^{-6}}}{{{({{0,012}^{2}}+{{0,085}^{2}})}^{3/2}}} \\ & \,E=\frac{9000}{{{({{0,012}^{2}}+{{0,085}^{2}})}^{3/2}}} \\ & E=14227535,39N/C \\ & \\ & b) \\ & E=\frac{kQ}{{{({{x}^{2}}+{{R}^{2}})}^{3/2}}} \\ & E=\frac{9\cdot {{10}^{9}}\cdot {{10}^{-6}}}{{{({{0,04}^{2}}+{{0,085}^{2}})}^{3/2}}} \\ & \,E=\frac{9000}{{{({{0,04}^{2}}+{{0,085}^{2}})}^{3/2}}} \\ & E=10856015,09N/C \\ \end{align}\ \)