An ideal gas is taken through the following three-step cycle
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Thermodynamics · Thermodynamics
Problem
An ideal gas is taken through the following three-step cycle, returning it to its initial state:
I. Isothermal expansion at 600K from volume V0 to 2V0 while in contact with a thermal reservoir.
II. Rapid adiabatic free expansion from 2V0 to 3V0 inside an insulated chamber.
III. Isothermal compression at 300K from 3V0 back to V0 while in contact with a second reservoir.
For which single step must the entropy change of the universe be positive, ensuring that the overall cycle is irreversible?
(a) Step III only
(b) Step II only
(c) Step I only
(d) All three steps equally