A point charge of -3. 00 μc is located in the center of a spherical cavity of radius 6. 90 cm inside an insulating spherical charged solid. The charge density in the solid is 7. 35 × 10^−4 c/m^3. Required:
a. Calculate the magnitude of the electric field inside the solid at a distance of 9.40 cm from the center of the cavity.
b. Find the direction of this electric field.