Five point charges, each of value +q coulomb, are placed on five vertices of a regular hexagon of side L meters. The magnitude of the force on the point charge of value -q coulomb, placed at the centre of the hexagon is…………….

Answer

9

Explanation

Force on due to charge at 1 and 4 are equal and opposite. Similarly, forces on –q due to charges at 2 and 5 are also equal and opposite. Therefore, net force on –q due to charges at 1, 2, 4 and 5 is zero. Only unbalanced force is between –q and + q at 3 which is equal to
`(1)/(4 pi epsi_(0)) .(q^(2))/(E^(2)) or 9.0xx 10^(9) (q^(2))/(L^(2)) ` (attraction)

Thus, variation of electric field (E) with distance (r) from the centre will be as shown