Which variable is classified as an extensive thermodynamic state variable?
**Heat and work distinction** heat is energy transfer due to temperature difference, random molecular motion, work is organized energy transfer due to macroscopic force, e.g., piston movement, both path functions depend on process, not state, internal energy U state function depends only on state (T for ideal gas), ΔU path independent, Q and W path dependent but Q-W = ΔU path independent. Extensive variables depend on the size or amount of the system and scale with it (e.g., halve when the system is halved). Volume ( V ) is extensive, while pressure ( P ) and temperature ( T ) are intensive, not dependent on
Ref: NCERT > Physics Book > Thermodynamics > Heat Transfer Work Distinction and Internal Energy Change