Can two conductors, having same nature of charge on them, attract each other?

Two charged conducting spheres of radii a and b are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on its flatten portions.

Assertion : Colloidal solution is electrically neutral. Reason : Due to similar nature of the charge carried by the particles, they repel each other and do not combine to form bigger particles.

What is the nature of force between two parallel conductors carrying current in the same direction?