So i got this question from another question posted on this website , in which the asker was asking if for a circle there will be infinite null points I have a few different question Firstly, i watched a video which shows why, in a system of 3 point masses placed at vertices of an equilateral triangle, there should exist 4 null points - in one the argument was made that on 2 different sides of a null point, the direction of the field changes - this is my first question, as to why does this happen. Furthermore, it was also said that the remaining null points should exist on the angle bisectors itself and then the electric field was calculated for a general point on it - this part also i didn't understand, as to how we can directly make this statement, what is the logic behind it Third doubt i have is which one of them is stable equilibrium and which is unstable? Fourth doubt - what happens when we just have 3 charges placed at the vertices of a scalene triangle, an isosceles triangle and a right angle triangle? Do we still get 3 points for these cases? I know for a fact that no matter which triangle you have - there always exists a null point at the incenter of the triangle. Will there exist any other points? 5th doubt - for four particles at the vertices of a square, there will be 5 null points, although, what is the exact location of the 4 other points? are they located symmetrically along the line joining the vertices to the center or midpoint of sides to the center?