Question

Two particles each having cahrege of 10 uc placed ata serperately

Answer 1

Given Mass m=5gCharge q=10 CDistance d= 10cmThe electric force on one of the particles due to the other is
F= 1/4π∈*q²/d²
The frictional force in limiting equilibrium
f=umg
As these two forces balance each other,
umg=1/4π∈*q²/d²
u=1/4π∈*q²/mgd²
Using the above formula and substituting the values you can find out coefficient of limiting friction.

☆hope it's help you☆

Answer 2

Three particles each having a charge 10*106, are placed at the vertices of an equilateral triangle of side 10*10-2 m.