a) Describe the heat capacity of a solid. b) The classical Dulong - Petit Law states that Cv = 3R where R is the ideal gas constant and Cv is the heat capacity at constant volume. However, experimentally Cv is found to vary with temperature as shown in Figure 1 at low temperatures Cy 3R O Figure 1 i. Use the Debye theory to explain the behavior of Cy ii. Show that at low temperatures, Cv varies as T3