84. The point charges Q1 = 30 μC and Q2 = −20 μC are at a distance of d = 20 cm from each other. Determine the electric field strength E at a point remote from the first charge by a distance of r1 = 30 cm, and from the second by r2 = 15 cm.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)