Adiabatic process: identify the correct defining properties An adiabatic process for a gas is characterized by no heat transfer; infer its implications for temperature and energy balance. Choose the correct option.

Concept
Adiabatic process: Q = 0. From the first law, ΔU = Q − W (sign convention: W is work done by the system). With Q = 0, ΔU = −W (or equivalently, the change in internal energy equals the negative of work by the system; equals work on the system). Temperature generally changes when a gas compresses/expands adiabatically.

Why all are true
(a) is the definition; (b) typically occurs in adiabatic expansion/compression; (c) follows directly from the first law with Q = 0.

Final Answer
All of the above