two spheres carrying charge q are hanging from a same point of suspension with the help of threads of length 1 m in a space free from gravity . the distance between them is?

1 answer

the downward force on each is mg.

from the vertical, then the angle to one string Theta is given by
kQQ/r^2mg=tanTheta

but sinTheta=r/2L

assuming small angles, sinTheta appx=tantheta

r/2L=kQQ/r^2mg
r^3=kQQL/mg

check that