Task 30029.

Two coaxial infinite cylinder of radius R and 2R charges are uniformly distributed with a surface density σ 1 and σ 2. Required: 1) using Theorem Ostrogradskii - Gauss find the dependence E (r) of the electric field from a distance of three areas: I, II, III. Take σ 1 = σ, σ 2 = - σ. 2) calculate the voltage E at a point remote from the cylinder axis at a distance r, and indicate the direction of the vector E. Take σ = 60 nC / m2, r = 3r. 3) Plot E (r).