I have a few Physics questions to be answered.here's one: A certain cylindrical wire carries current.

I have a few Physics questions to be answered...here's one:A certain cylindrical wirecarries current. We draw acircle of radius r around itscentral axis as seen in theFigure (a) to determine thecurrent i within the circle.The Figure (b) showscurrent i has a function ofr 2 . (a) Is the currentdensity uniform? (b) If so,what is its magnitude?picture attached: