Which of the following statements are correct when related to a thermodynamic system?

1) lnternal energy is a property

2) lnternal energy is path independent

3) lnternal energy is path dependent

4) lntemal energy is the area under the pv curve

Explanation:

Point functions:

• Point functions are defined as the thermodynamic variable which depends on end states only i.e. initial and final states. They do not depend upon the path followed.
• The differential of point functions is exact.
• Pressure, temperature, volume, entropy, enthalpy, internal energy etc are point functions.

Path functions:

• Path functions are defined as the thermodynamical variables which depend on the way/path in which the thermodynamical system achieved the initial and final states.
• The differential of path functions is inexact.
• Heat, work and entropy generation are path functions.

Also, the area under the PV curve gives the work done, and work done will be equal to change in internal energy only when the process is adiabatic which is not the case here.