Two parallel infinite plates are chaged oppositely with densites `+sigma _(2)` four point 1,2,3,4 are located as difference between 2 and 1 is `V_(2-V_(1) `(a) which of the densites `(+sigma _(1) or sigma _(2)` is larger in magnitude? (b) what is the potential diffence beween 4 and 3 ?