91. In a flat horizontal capacitor, a charged droplet of mercury is in equilibrium at an electric field strength of E = 6 ∙ 104 V / m. Drop charge q = 8 • 10−19 C. Find the radius r of the drop. Mercury density ρ = 13.6 ∙ 103 kg / m3.

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