1. The problem statement, all variables and given/known data For a metal bar of cross sectional area A, the rate of flow of heat along the bar is given by the expression: Q=-KA(dT/dx) where K is the thermal conductivity of the material of the bar, and T and x refer to temperature and the distance measured from the high temperature end of the bar respectively. Use this information to solve the following problem. A spherical heat source of radius a sits at the centre of a solid sphere of radius b>a. The material of the sphere has thermal conductivity K. The source emits heat equally in all directions at the rate Q per second and the outside of the sphere is held at a constant temperature T0. Determine the temperature T at the surface of the source. Some help needed please.