question_answer

State the first law of thermodynamics.

Answer:

                According to the first law of thermo- dynamics, the amount of heat \[\Delta Q\] absorbed by a system capable of doing mechanical work is equal to the sum of the increase in internal energy \[\Delta U\]of the system and the external work\[\Delta W\] done by the system. Mathematically, \[\Delta Q=\Delta U+\Delta W=\Delta U+P\Delta V.\]