(Qualitative identification of reversibility in everyday situations)
(i) Define a reversible thermodynamic process.
(ii) State any two essential conditions that must be satisfied for a process to be truly reversible.
(iii) Examine the following five situations and, for each one, state whether the process is reversible or irreversible. Give one clear reason for your choice in every case.
A. Melting of ice at exactly 0 °C in contact with water at 0 °C.
B. Rapid adiabatic expansion of a gas through a porous plug.
C. Slow, frictionless compression of an ideal gas in a cylinder fitted with a frictionless, perfectly conducting piston, the external pressure being decreased infinitesimally at each step.
D. Mixing equal masses of water at 40 °C and 20 °C in an insulated bucket.
E. Oscillation of an ideal simple pendulum in vacuum without air resistance.