Question

Four equal charges q are sitting on the vertices of an square (imaginary). How many neutral point will be formed inside the plane of the square?

Answer 1

according to Columb's equation \[F=K Q1Q2divR ^{2}\] each charge will act a force on the other charges. this Force have a Field (E), which have equation \[E=KQ1divR ^{2}\]. that mean the Force Field of each charge depen on the distance.
the point inside the plane , where there are neutral this mean the sum of the force Fields = Zero \[\sum_{?}^{?} E=Zero\]
according to Force Field equation \[K Q divR _{1} ^{2} +K Q divR _{2} ^{2}+K Q divR _{3} ^{2}+K Q divR _{4} ^{2}=Zero\]
after Maths we will find the answer id
only one point in the center of the square where vectors opposite and equal