Two point charges q1 and q2 are kept at a distance of r12 in air..If an external electric field is applied on the system, write the expression for the total energy of this system.

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 points charges +10muC and -10muC are separated by a distance of 40 cm in air. Calculate the electrostatic potential energy of the system, assuming the zero of the potential energy to be at infinity.

Two point charge +q and -q are separated by a distance d. Where besides at infinity is the electric potential 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 point charges q and-q are placed at a distance 2a part. Calculate the electric field at a point P situated at a distance r along the axial line of an electric dipole. What is the electric field when r>>a ? Also, give the direction of elctric field w.r.t. electric dipole.

Two point charges 4Q and Q are separated by a distance of 1 m in air. Also calculate the electrostatic potential energy of the system of two charges, taking Q = 2 xx 10^-7C .

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? .

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.