Задача 00134.

Between oppositely charged parallel plates, a voltage of 3 kV is in equilibrium with a grain of dust with a mass of 5 ng. how much it is necessary to reduce the potential difference so that the dust particle remains in equilibrium if its charge changes by 100,000 electrons. The distance between the plates is 5 cm, the buoyancy force of the air can be neglected.

Detailed solution with a brief record of the conditions, formulas and laws used in the decision, the conclusion of the calculation formula and the answer.
If you have any questions about the decision, write. I will try to help. File in image format.