Problem: Graphical Analysis, Differentiation Figure 21-43 is a plot of electric potential as a function of radial distance for some spherically symmetric object. Do not assume a reference of zero electric potential at infinite distance. (a) Write down a function for electric potential as a function of radial distance to approximate the data. (b) Use your answer to determine an expression for the electric field. (c) What type of object or objects are consistent with these observations? (d) What must be the approximate surface charge density on the object? -30.0 -32.5 -35.0 -37.5 Electric potential (V) -40.0 -42.5 -47.5- -50.0- 0.000 0.500 1.000 1.500 2.000 Radial distance (m) Figure 21-43 Problem 98