91. An electrostatic field is created by two infinite parallel planes charged by uniformly opposite charges with surface densities σ1 = 3 nC / m2 and σ2 = −6 nC / m2. Determine the strength of the electrostatic field: 1) between the planes; 2) outside the planes

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