Two charged spheres of -20 C and 60 C are kept at a certain distance. They are touched and kept again at the same distance. What is the ratio of force experienced before and after?

Step-by-step solution

Let the charges on the two spheres be q₁ = -20 C and q₂ = 60 C . Let the distance between them be r . The electrostatic force before touching is given by Coulomb's law: F₁ = k |q₁ q₂| r^2 = k |(-20)(60)| r^2 = k 1200 r^2 When the spheres are touched, the total charge is redistributed equally between the two identical spheres. The new charge on each sphere is: q' = q₁ + q₂ 2 = -20 + 60 2 = 40 2 = 20 C The electrostatic force after touching is: F₂ = k |q' q'| r^2 = k |(20)(20)| r^2 = k 400 r^2 The ratio of the force