Question

does the electric potential increasese or decrease alone the electric line of force?

Answer 1

By convention potential is measured as the work done on a unit positive test charge to from infinity to that point, now lines of force are in most case directed from a positive charge to a negative charge of from a positive charge to infinity or from infinity to a negative charge, so coming near to a negative charge promotes boundness or increase of negative potential, thus thinking by this trend moving along line of force the potential must decrease, suppose you are moving from a positive test charge to infinity so obviously your potential decrease from maximum to zero, and then again approching from infinity to negative charge your potential becomes negative, so moving along a line of force your potential should decrease.