Question

V. HEAT CAPACITY OF PLATINUM The usual expression for the Debye temperature involves the speed of sound, v. However, this result is too simplistic because there are two types of waves in the solid: transverse waves which travel at a speed of v, and longitudinal waves, which travel at a speed of vi. In general these speeds are not the same. a) [2 marks] Derive a new expression for the Debye temperature using the identity that the aver- age speed v can be found from, 3 0 ,3 0 0 Explain why there is a factor of 2 associated with the v term. b) [4 marks] Using the expression you found in part a), work out the Debye temperature of platinum, given that vi - 3260 m/s and vt -1730 m/s. Use the fact that the density of platinum is 21.4g/cm3 and its molar mass is 195.1 g/mol. c 4 marks] Estimate the total heat capacity of 1 mole of platinum at 4 Kelvin

Answer 1

i uan By assuming tiven values we haue 2 14467 хо .3804 X0 - HXok