Question

The electrostatic force on a small sphere of charge 0.4 µ C due to another small sphere of charge 0.8 µ C in air is 0.2 N. 

(a) What is the distance between the two spheres? 

(b) What is the force on the second sphere due to the first?

Answer 1

Here,

q₁ = 0.4 μC = 0.4 x 10^-6 C

q₂ = -0.8 μC = -0.8 x 10^-6 C

(a) Force on charge q₁ due to q₂, 

F₁₂ = 0.2 N

r = 0.12 m

(b) Force of charge q₂ on q₁

F₂₁ = F₁₂ = 0.2 N(attractive in nature)