A charge q is placed at the centre of line joining two equal charges Q. Show that the system of three charges will be in equilibrium if q = -Q/4

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:

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.

Three charges each of value q are placed the corers of an equilaterla triangle. A fourth charge Q is placed at the centre of the triangle. If Q = -q, will the charges at the corners move towards the centre or fly away from it?

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 charges each of value q are placed the corners of an equilaterla triangle. A fourth charge Q is placed at the centre of the triangle. For what value of Q, will the charges remain stationary? In this situation, how much work is done in removing the charges to infinity?

A thin metallic spherical shell of radius R carries a charge Q on its surface. A point charge Q/2 is placed at its centre C and another charge +2Q outside the shell at a distance r from the centre as shown in figure. Find the force on the charge at the centre of shell and at point A.

A thin metallic spherical shell of radius R carries a charge Q on its surface. A point charge Q/2 is placed at its centre C and another charge +2Q outside the shell at a distance r from the centre as shown in figure. Find the electric flux through the shell.

A charge q is placed at the centre of a cube of side l . What is the electric flux passing through two opposite faces of the cube?

Five charges, q each, are placed at the corners of a regular pentagon of side a as shown in the figure. What will be the electric field at O, the centre of the pentagon? What will be the electric field at O, fi the charge from one of the corners (Say A) is removed? What will be the electric field at O, if the charge q at A is repalced by - q?