Question

We can describe the state of a substance in thermodynamic equilibrium using two state variables. What are these two variables?

(a) Density and temperature

(b) Density and pressure

(c) Pressure and Temperature

(d) Velocity and Temperature

This question was posed to me at a job interview.

My question is based upon Equations of State topic in portion Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

Correct option is (a) Density and temperature

Easy explanation: There are four thermodynamic variables – density, temperature, pressure and specific internal energy. Among these, pressure and specific internal energy can be represented using density and temperature.