i didn't write the section and would welcome you to rewrite it about it i thought two things were true the capacity per particle of thermal energy per degree of freedom is proportional to absolute temperature with the boltzmann constant k as the constant of proportionality also at least in engineering thermodynamics books calling heat a low grade energy in comparison to non random mechanical or electrical energy is common because to convert this low grade energy to a high grade energy a heat engine is used and their cannot be efficient but to convert electical or mechanical energy into heat is always efficient