What establishes thermal equilibrium and forms the basis for temperature measurement?

Zeroth Law of Thermodynamics

True or False: Energy can be created during thermodynamic processes.

False. Energy can neither be created nor destroyed, only converted between forms.

For a closed system, Q - W = _____

ΔU (change in internal energy)

Which process has constant entropy throughout?
A) Isothermal
B) Isobaric
C) Isentropic
D) Isochoric

C) Isentropic

What happens when two systems in thermal equilibrium with a third system?

They are in thermal equilibrium with each other

In throttling devices, what property remains constant across the device?

Enthalpy (h₁ = h₂)

True or False: Entropy can decrease for an isolated system.

False. Entropy of isolated systems never decreases, only increases or stays constant.

The Kelvin-Planck statement relates to which thermodynamic law?

Second Law of Thermodynamics

For nozzles and diffusers, h₁ + V₁²/2 = _____

H₂ + V₂²/2

Which efficiency represents maximum possible for heat engines?
A) Diesel efficiency
B) Otto efficiency
C) Carnot efficiency
D) Rankine efficiency

C) Carnot efficiency

What does entropy measure in thermodynamic systems?

Molecular disorder or randomness

True or False: Temperature must be in absolute units for Carnot efficiency calculations.

True. Rankine or Kelvin scales must be used.

For reversible processes, dS = _____

ΔQᵣₑᵥ/T

A polytropic process with n = 0 represents which type?
A) Isothermal
B) Isobaric
C) Isochoric
D) Isentropic

B) Isobaric

What causes exergy destruction in thermodynamic processes?

Irreversibilities and entropy generation

For steady-flow turbines and compressors, Ẇ = ṁ(_____ - _____)

H₁ - h₂

True or False: All real heat engines have efficiency less than Carnot efficiency.

True. Carnot efficiency is the theoretical maximum.

What does COP stand for in refrigeration systems?

Coefficient of Performance

The Clausius inequality states: ∮ δQ/T _____ 0

≤

Which process follows the relation Pvⁿ = constant?
A) Polytropic
B) Isothermal only
C) Isentropic only
D) Adiabatic only

A) Polytropic

What is the entropy of pure crystalline substance at absolute zero?

Zero (Third Law of Thermodynamics)

For ideal gas isentropic process: T₂/T₁ = (P₂/P₁)^_____

(γ-1)/γ

True or False: Gibbs free energy equals H - TS.

True. G = H - TS

Riddle: I am conserved but my quality degrades with irreversibility. What am I?

Energy

What represents maximum useful work obtainable from a system at equilibrium?

Exergy (available energy)

For heat pumps, COPₕₚ = Qₕ/_____

Wₙₑₜ