Two point charges`+Q_1` and `Q_2` are placed r distance apart. Obtain the expression for the amount of work done to place a third charge `Q_3` at the midpoint of the line joining the two charges.

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? .

Two point charges +5muC and -5muc are placed at a distance 5 cm apart. Draw the equipotential surfaces of the system.

The point charges Q and -2Q are placed at some distance apart. If the electirc field at the location of Q is E, the electric field at the location of -2Q will be

Two point charges q_1 and q_2 are kept at a distance of r_(12) in air. Deduce the expression for the electrostatic potential energy of the system.

Two charges equal to +20 muC and -10muC are placed at points 6 cm apart. Find the value of the potential at a point distant 4 cm on the right bisector of the line joining the two charges.

Two point electric charges of unknown magnitude and sign are placed at a distance 'd' apart. The electric intensity is zero at a point, not between the charges but on the line joining them. Write two essential conditions for this to happen.

Two point electric charges of unknown magnitude and sign are placed a distance apart. The electric field intensity is zero at a point not between the charges but on the line joining them. Write two essential conditions for this to happen.

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?