A prototype of a tube with a square cross section is to be fabricated using lithography

Consider a spherical container of inner radius , outer radius r2, and thermal conductivity k. express the boundary condition on the inner surface of the container for steady one-dimensional conduction for the following cases: (a) specified temperature of 50°c, (b) specified heat flux of 30 w/m2 toward the center, (c) convection to a medium at t with a heat transfer coefficient of h