Consider a homogeneous spherical piece of radioactive material of radius ro 5 0.04 m that is generating heat at a constant rate of e · gen 5 5 3 107 w/m3. the heat generated is dissipated to the environment steadily. the outer surface of the sphere is maintained at a uniform temperature of 110°c and the thermal conductivity of the sphere is k 5 15 w/m·k. assuming steady one-dimensional heat transfer, (a) express the differential equation and the boundary conditions for heat conduction through the sphere, (b) obtain a relation for the variation of temperature in the sphere by solving the differential equation, and (c) determine the temperature at the center of the sphere.