Heat conduction from a sphere to a stagnant fluid. A heated sphere of radius R is suspended in a large, motionless body of fluid. It is desired to study the heat conduction in the fluid surrounding the sphere in the absence of convection. (a) Set up the differential equation describing the temperature T in the surrounding fluid as a fuction of r, the distance from the center of the sphere. The thermal conductivity K of the fluid is considered constant. (b) Integrate the differential equation and use these boundary conditions to determind the intregration constants: at r = R, T = TR; and r = "infinity", T = T"infinity"