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

Explanation

If there had been a sixth charge `+q` at the remaining vertex of hexagon force due to all the six charges on `-q` at O will be zero (as the forces due to individual charges will balance each other), i.e.,
`vecF_(R)=0`

Now if `vecf` is the force due to the sixth charge and `vecF` due to remaining five charges, `vecF+vecf=0` i.e, `vecF=-vecf`
or `F=f=(1)/(4piepsilon_(0))(qxxq)/(L^(2))=(1)/(4piepsilon_(0))[(q)/(L)]^(2)`