Physics - Heat & Thermo Question with Solution | TestHub
"The coefficient of linear expansion is proportional to the heat capacity of a substance." Explain. Evaluate the following statements.
Statement I: Expansion is exactly proportional to heat capacity for every material with the same constant.
Statement II: For one solid, a Gruneisen relation can make expansion track heat capacity approximately; the proportionality is not universal across substances.
Options:
Answer:
Solution:
For a solid, the Gruneisen relation gives , where is the Gruneisen parameter and the compressibility. Expansion comes from the anharmonic part of lattice vibrations, and its temperature dependence follows the vibrational heat capacity (both fall toward zero at low temperature). So for a given solid the statement is approximately true as temperature varies. It is not a rule that compares different substances (copper and lead differ in ). Statement I is false and Statement II true. Correct option: (C).
