A uniform non-metallic annular cylinder of inner radius $r_1$, outer radius $r_2$, length $l_0$ is maintained with its inner surface at $100^{\circ} \mathrm{C}$ and its outer surface at $0^{\circ} \mathrm{C}$.
(a) What is the temperature distribution inside?
(b) If it is then placed in a thermally insulated chamber of negligible heat capacity and allowed to come to temperature equilibrium, will its entropy increase, decrease or remain the same? Justify your answer.
FIGURE CAN'T COPY.