Find out the expression for the potential energy of a system of three point charges `q_1, q_2 and q_3` located at `vecr_1, vecr_2 and vecr_n` w.r.t the common origin O.

Deduce an expression for the electric field vecE due to a system of two harges q_1 and q_2 with position vectors vecr_1 and vecr_2 at a oint vecr w.r.t the common origin O.

Deduce the expression for the potential energy of a system of two point charges q_1 and q_2 brought from infinity to the points vecr_1 and vecr_2 respectively in the presence of electric field vecE .

Find the electrostatic potential energy of the configuration of four charges +q,-q,+q and -q placed at the four corner A,B,C and D of a square of side r.

Obtain an expression for potential energy of the configuration of three charges Hence generalise the result for a system of n point charges?

A charge Q located at a point rarrr is in equilibrium under the combined electric field of three charges q_1, q_2 and q_3 if the charges q_1, q_2 are located at the points rarrr_1 and rarrr_2 respectively, find the direction of the force on Q, due to q_3 , in term of q_1,q_2,q_3 rarrr, rarrr_1, and rarrr_2

Three charges -q, Q and -q are placed at equal distances on a striaght line. If the potential energy of the system of three charges is zero, then what is the ratio of Q:q?

Three point charges q, 2q and 8q are to be placed on a . 9cm long straight line. Find the . positions where the charges shouldbe placed such that the potential energy . of this sysrem is minimum. In this situation, what is the . electric field at the charge q due to the other two charges?

The two graphs drawn below show the variation electrostatic potential (V) with 1/r (r being distance of the field point from the point charge) for two point charges q_1 and q_2 What are the signs of the two charges?

In figure, the two graphs show the variation of electrostatic potential (V) with 1/r (r being distance of the field point form the point charge) for two point charges q_1 and q_2 What are the signs of the two charges?