Four point charges each +q is placed on the circumference of a circle of diameter `2 d` in such a way that they form a square. The potential at the centre is

Four point charges each '+q' is placed on the circumference of a circle of diameter 2d in such a way that they form a square. The potential at the centre is

Four point changes each +q is placed on the circumference of a circle of diameter 2d in such a way that they form a square. The potential at the centre of the circle (in CGS) is

In vacuum, three small spheres are placed on the circumference of a circle of radius r in such a way that an equilateral triangle is formed. If q be the charge on each sphere, determine the intensity of electric field and potential at the centre of the circle.

Three small spheres are placed on the circumference of a circle of radius r in such a way that an equilateral triangle is formed. If the charge of each sphere is q, the electric field intensity at the centre of the circle will be __________. [fill in the blanks]