5. Kittel, Ch4-14, Heat capacity of liquid He at low temperature. The velocity of longitudinal sound waves in liquid He at temperatures below 0.6K is 2.383x10 cms. There are no transverse sound waves in the liquid. The density is 0.145gcm³. (a) Calculate the Debye temperature. (b) Calculate the heat capacity per gram on the debye theory and compare with the experimental value C₁ = 0.0204×7³, in Jg¹K¹. The T³ dependence of the experimental value suggests that phonons are the most important excitations in liquid He below 0.6K. Note that the experimental value has been expressed per gram of liquid. The experiments are due to J. Wiebes, C. G. Niels-Hakkenberg, and H. C. Krammers, Physca 32, 625 (1957).

5. Kittel, Ch4-14, Heat capacity of liquid He at low temperature. The velocity of longitudinal sound waves in liquid He at temperatures below 0.6K is 2.383x10 cms. There are no transverse sound waves in the liquid. The density is 0.145gcm³. (a) Calculate the Debye temperature. (b) Calculate the heat capacity per gram on the debye theory and compare with the experimental value C₁ = 0.0204×7³, in Jg¹K¹. The T³ dependence of the experimental value suggests that phonons are the most important excitations in liquid He below 0.6K. Note that the experimental value has been expressed per gram of liquid. The experiments are due to J. Wiebes, C. G. Niels-Hakkenberg, and H. C. Krammers, Physca 32, 625 (1957).