At what distance from charge `+Q_1` on the line joining the two charges `(in terms of Q_1, Q_2 and r)` will this work done by zero?

Two point charges 4Q and Q are separated by a distance of 1 m in air. At what point on the line joining the two charges is the electric field intensity zero?

Two identical point charges of charge Q are kept at a distance r from each other. A third point charge is placed on the line joining the above two charges, such that all the three charges are in equilibrium. Calculate the magnitude and location of the thrid charge.

Two point charges q and -q is placed at a distance 2a apart.Calculate the electric field at a point P situated at a distance r along the perpendicular bisector of the line joining the charges. What is the electric field when r gtgt a ? Also, give the direction of electric field W.r.t. electric dipole moment? .

If q_1q_2>0 , what is the nature of force between the two charges?

If q_(1)q_(2) > 0 , What is the nature of force between the two charges ?

A charge q is placed at the centre of the line joining two exactly equal positive charges Q. the system of three charges will be in equilibrium, if q is equal to:

Three points charges +q,+2q and Q are placed at the three vertices of an equilateral triangle. Find the value of charge Q (in terms of q), so that electric otential energy of the system is zero.

Two point charges 4 mu C and -2 muC are separated by a distance of 1 m in air. At what point on the line joining the charge is electric potential zero?