Heat and Thermodynamics

9.1 Limitations of the First Law of Thermodynamics

All experimental methods developed so far for the investigation of the law of equivalence of heat and mechanical work are only methods of conversion of mechanical work into heat and not heat into mechanical work. The law of equivalence is

 

 

This is the first law of thermodynamics in restricted sense and is applicable only when mechanical work is converted into heat. When heat is converted into work,

 

 

except under some special circumstances to be developed later on. The natural law of conversion ...