Find the potential between the cylinders C₁: |z| = 1 (potential U₁ = 0) and C₂: |z - c| = c (potential U₂ = 220 V), where 0 < c < 1/2. Sketch or graph equipotential lines and their orthogonal trajectories for c = 1/4. Can you guess how the graph changes if you increase c (< 1/2)?