Two point charges having a total charge Q are distance x apart. Find the value of each so that the force they exert on each other is maximum.

Two point charges having a total charge Q are at a distance x apart. Find the value of each charge, so that the force they exert on one another is maximum.

Two point charges having equal charges separated by 1m distances experience a force of 8N. What will be the force experienced by them , if they are held in water, at the same distance ? ( take , K_(" water" ) = 80 )

Two charged particles are a distance 1 mm apart. Find the minimum Coulomb force between them.

Two point charges Q and - 3Q are placed some distance apart. If the electric field at the location Q is E, then what is the electric field at the location - 3Q?

Four point charges each of charge -4muC are placed at the four corners of a square such that they are in equilibrium when a charge q is placed at its centre. Find q.

A and B are two point charges kept at a certain distasnce apart. If the charge on A is reduced to one-quarter, that on B doubled and at the same time distance between them reduce to one-half of its previous value, how does the force between them change?