Written Response: (4 marks) Students collect information regarding electric field around an unknown charged pith ball. They graphically analyze the data and produce the following curve straightened graph. A systematic error seems to be present but a linear relationship between electric field strength and inverse of the distance from charge squared exists. Electric Field Strength as a function of the Inverse of the Distance From Charge Squared 9000 8000 7000 6000 5000 Electric Field Strength, E, (N/C) 4000 3000 2000 1000 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Inverse of the Distance from Charge Squared 1/r2 (1/m2) Use the slope of the graph to determine the value of the unknown charge