Calculate the magnitude of the electric field 9.25 cm from the center of the sphere. Answer in units of N/C.

For a solid sphere; r > R

E = Q/4πεor^2

r = 9.25 cm = 0.0925m

plugging the values into the formula;

Volume within sphere of radius 9.25 cm = 4/3π X (0.0925 m) ^3

Charge per unit volume = 21.2/[4/3π X (0.0925m) ^3] µC

= 6.39µC

By Coulomb's law,

the electric field = 9 X 10^9 X 6.39 X 10^-6 / (0.0925) ^2

= 9 X 10^9 X 6.39 X 10^-6/0.0925^2

= 672.14KN/C