In an insulated pipe with no heat transfer, the flow is described as which?

In an insulated pipe with no heat transfer, the flow is described as which?

• A. Adiabatic
• B. Isothermal
• C. Isobaric
• D. Thermally insulated

Answer: (A)

No heat transfer across the boundaries means the process is adiabatic. In an insulated pipe, the fluid exchanges no heat with its surroundings, so Q = 0. With no heat added or removed, changes in the fluid’s internal energy come from work done on or by the fluid as it moves, so the temperature can change due to compression or expansion. That’s why the flow is described as adiabatic. Isothermal would require heat transfer to keep temperature constant, which isn’t present here. Isobaric would require constant pressure, which isn’t given. Saying the pipe is thermally insulated describes the boundary condition, not the process name itself.

No heat transfer across the boundaries means the process is adiabatic. In an insulated pipe, the fluid exchanges no heat with its surroundings, so Q = 0. With no heat added or removed, changes in the fluid’s internal energy come from work done on or by the fluid as it moves, so the temperature can change due to compression or expansion. That’s why the flow is described as adiabatic.

Isothermal would require heat transfer to keep temperature constant, which isn’t present here. Isobaric would require constant pressure, which isn’t given. Saying the pipe is thermally insulated describes the boundary condition, not the process name itself.