What is the excess number of electrons that must be placed on each of two small spheres spaced 3 cm apart so that a force of repulsion that acts between them becomes 10⁻¹⁹ N?
Physics · Electrostatic
JEE Mains Advanced

Question

What is the excess number of electrons that must be placed on each of two small spheres spaced 3 cm apart so that a force of repulsion that acts between them becomes 10⁻¹⁹ N?

G1 Physics · Accepted Answer

Step 1: Identify the relevant electrostatic principle—Coulomb's law, superposition, Gauss's law, potential-energy conservation or conductor boundary conditions. Step 2: Write the corresponding equation using the quantities in the question and simplify the geometry. Step 3: Substitute the given values and compare with the alternatives. Final: 625.