Question

What is the force between two small charged spheres having charges of 2 × 10^–7C and 3 × 10^–7 C placed 30 cm apart in the air?

Answer 1

Given,

The Charge on the 1^st sphere and 2^nd sphere is q₁ = 2 x 10^-7 C and q₂ = 3 x 10^-7 C

The distance between two charges is given by r = 30cm = 0.3m

The electrostatic force between the spheres is given by the relation :

F = 1/4πϵ_o​ x q₁​q_2​​/r²

Here,

ϵ_o​ = permittivity of free space and,

1/4πϵ_o​ = 9 x 10⁹ Nm²C^-2   

Force, F = 9x10⁹x2x10^-7x3x10^-7 / (0.3)²​ = 6 x 10^‑3 N.

The force between the charges will be repulsive as they have the same nature.