1. The problem statement, all variables and given/known data 2. Relevant equations E= kq/(r^2), E*dA = Q/e0 3. The attempt at a solution Typically I understand how to interpret basic graphs such as going for V (potential) vs x graph to Electric field vs x graph by finding the slope of V since E= -grad V...and from their it's basic algebra. As for going from E vs r to charge density, I'm a bit lost on how to do so for #2. Is there a formula to follow such as what I described above in interpreting these graphs and possibly something to help me see the big picture? My attempt at this problem is....and correct me if I am wrong... From 0-a it seems that the electric field of the spherical object is increasing, so I'd say it's an insulator. From a-b there is a drop of 1/r graph...so imagining that we are far away the e-field would approach zero, so I'd say it would be "space"---that is what they meant by space right?--(nothing present/no material) Thank you for your help!