There are two point charges q1 and q2 in the vacuum, where q1 is positive, q2 is negative, q1=8q2, and the other point charge p distance q1 is r1 distance q2 is r2
It can be seen from the superposition principle of electric field that: the electric field strength generated by two charges at point P should be calculated first, and then solved according to the vector synthesis rule. The electric field strength of point charge Q1 at point P is E1=k, and the direction is as shown in the figure; The field strength of Q2 at P is E2=k, and the direction is as shown in the figure. To make the direction of the combined field strength E parallel to the connecting line of two point charges, then △ PE1E is similar to △ Q1PQ2. According to the similar triangle principle, we can get:, which can be solved by:=2