Question

Which of the following thermodynamic process $\Delta Q = 0$?

• A. Isothermal Process
• B. Isobaric Process
• C. Isochoric Process
• D. Adiabatic Process

Answer 1

Answer:

D. Adiabatic Process

• Adiabatic Process: The thermodynamic process defined by the condition ΔQ = 0 is known as an adiabatic process. In this process, there is no heat exchange (transfer) between the system and its surroundings.

• First Law of Thermodynamics: According to the first law of thermodynamics, ΔQ = ΔU + ΔW. If ΔQ = 0, the equation simplifies to ΔU = -ΔW. This indicates that any work done by the system (ΔW > 0) comes at the expense of its internal energy (ΔU decreases), while work done on the system (ΔW < 0) increases its internal energy.

• For an ideal gas undergoing a reversible adiabatic process, the relationship between pressure (P) and volume (V) is given by PV^γ = constant, where γ (gamma) is the adiabatic index or the ratio of specific heats (C_p/C_v).

• Examples in Nature:

  • Rapid expansion of steam in a steam engine.

  • The compression stroke in an internal combustion engine (petrol or diesel).

  • Sound wave propagation in a gas.

  • Cloud formation in the atmosphere due to the rapid expansion of rising air.

  • Isothermal: ΔT = 0 (temperature remains constant).

  • Isobaric: ΔP = 0 (pressure remains constant).

  • Isochoric: ΔV = 0 (volume remains constant).