Consider a point charge surrounded by a gaussian sphere. In the derivation of the formula, we said that E is constant everywhere on the sphere. Hence, we used Flux= EA.. However, isn't the E created on the surface is due to one field line out of the pint charge. I mean the formula kQ/r^2 is the field of the charge in a particular direction? I need clarification in this. Here, i just want to know kq/r^2.. What does it respond to?