90. A droplet of oil with a radius of 1 μm, carrying a charge of twenty electrons, is in equilibrium in the field of a horizontally located flat capacitor when a voltage of 82 V is applied to it. The distance between the plates is d = 8 mm. What is the charge of an electron? The density of the oil is 800 kg / m3.

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