Multiple Choice
12.1 Zeroth Law of Thermodynamics: Thermal Equilibrium
Name any two industries in which the principles of thermodynamics are used.
- aerospace and information technology (IT) industries
- industrial manufacturing and aerospace
- mining and textile industries
- mining and agriculture industries
12.3 Second Law of Thermodynamics: Entropy
Why does entropy increase during a spontaneous process?
- Entropy increases because energy always transfers spontaneously from a dispersed state to a concentrated state.
- Entropy increases because energy always transfers spontaneously from a concentrated state to a dispersed state.
- Entropy increases because pressure always increases spontaneously.
- Entropy increases because temperature of any system always increases spontaneously.
A system consists of ice melting in a glass of water. What happens to the entropy of this system?
- The entropy of the ice decreases, while the entropy of the water cannot be predicted without more specific information.
- The entropy of the system remains constant.
- The entropy of the system decreases.
- The entropy of the system increases.
12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators
Which of these quantities needs to be zero for efficiency to be 100 percent?
- ΔU
- W
- Qh
- Qc
Which of the following always has the greatest value in a system having 80 percent thermal efficiency?
- ΔU
- W
- Qh
- Qc
In the equation Q = Qh − Qc, what does the negative sign indicate?
- Heat transfer of energy is always negative.
- Heat transfer can only occur in one direction.
- Heat is directed into the system from the surroundings outside the system.
- Heat is directed out of the system.
What is the purpose of a heat pump?
- A heat pump uses work to transfer energy by heat from a colder environment to a warmer environment.
- A heat pump uses work to transfer energy by heat from a warmer environment to a colder environment.
- A heat pump does work by using heat to convey energy from a colder environment to a warmer environment.
- A heat pump does work by using heat to convey energy from a warmer environment to a colder environment.