Test Bank For Thermodynamics An Engineering Approach 8Th edition By SI Units

Test Bank For Thermodynamics An Engineering Approach 8Th edition By SI Units

Multiple-Choice Test Problems

Chapter 2:  Energy, Energy Transfer, and General Energy Analysis

Çengel/Boles – Thermodynamics: An Engineering Approach, 8^th Edition

(Numerical values for solutions can be obtained by copying the EES solutions given and pasting them on a blank EES screen, and pressing the Solve command. Similar problems and their solutions can be obtained easily by modifying numerical values.)

Chap2-1 Heating by Resistance Heater 

A 1.5-kW electric resistance heater in a room is turned on and kept on for 20 min. The amount of energy transferred to the room by the heater is

(a) 1.5 kJ (b) 60 kJ (c) 750 kJ (d) 1800 kJ (e) 3600 kJ 

Answer  (d) 1800 kJ

Solution Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 

We= 1.5 “kJ/s”

time=20*60 “s”

E_total=We*time “kJ”

“Some Wrong Solutions with Common Mistakes:”

W1_Etotal=We*time/60 “using minutes instead of s”

W2_Etotal=We “ignoring time”

Chap2-2 Heat Supplied by Vacuum Cleaner

A 200 W vacuum cleaner is powered by an electric motor whose efficiency is 70%. (Note that the electric motor delivers 200 W of net mechanical power to the fan of the cleaner). The rate at which this vacuum cleaner supplies energy to the room when running is  

(a) 140 W  (b) 200 W   (c)  286 W  (d) 360 W (e) 86 W  

Answer  (c)  286 W  

Solution Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 

Eff=0.70

W_vac=0.2 “kW”

E=W_vac/Eff  “kJ/s”

“Some Wrong Solutions with Common Mistakes:”

W1_E=W_vac*Eff “Multiplying by efficiency”

W2_E=W_vac “Ignoring efficiency” 

W3_E=E-W_vac “Heat generated by the motor” 

Chap2-3 Heat Convection 

A 40-cm-long, 0.6-cm-diameter electric resistance wire is used to determine the convection heat transfer coefficient in air at 25∞C experimentally. The surface temperature of the wire is measured to be 150∞C when the electric power consumption is 90 W. If the radiation heat loss from the wire is calculated to be 30 W, the convection heat transfer coefficient is 

(a)  0.48 W/m2.∞C (b) 127 W/m2.∞C (c) 63.7 W/m2.∞C (d) 95 W/m2.∞C (e) 200 W/m2.∞C “

Answer  (c) 63.7 W/m2.∞C

Solution Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 

L=0.4 “m”

D=0.006 “m”

A=pi*D*L “m^2”

We=90 “W”

Ts=150 “C”

Tf=25 “C”

We-30= h*A*(Ts-Tf) “W”

“Some Wrong Solutions with Common Mistakes:”

We-30= W1_h*(Ts-Tf) “Not using area”

We-30= W2_h*(L*D)*(Ts-Tf) “Using D*L for area”

We 30= W3_h*A*(Ts-Tf) “Adding Q_rad instead of subtracting”

We= W4_h*A*(Ts-Tf) “Disregarding Q_rad”

Chap2-4 Heat Convection and Radiation 

A 1.5-m² black surface at 120∞C is losing heat to the surrounding air at 30∞C by convection with a convection heat transfer coefficient of 18 W/m².∞C, and by radiation to the surrounding surfaces at 10∞C. The total rate of heat loss from the surface is 

(a) 1483 W (b) 2430 W (c) 2448 W (d) 3913 W (e) 2609 W

Answer  (d) 3913 W

Solution Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 

sigma=5.67E-8 “W/m^2.K^4”

eps=1

A=1.5 “m^2”

h_conv=18 “W/m^2.C”

Ts=120 “C”

Tf=30 “C”

Tsurr=10 “C”

Q_conv=h_conv*A*(Ts-Tf)  “W”

Q_rad=eps*sigma*A*((Ts 273)^4-(Tsurr 273)^4) “W”

Q_total=Q_conv Q_rad “W”

“Some Wrong Solutions with Common Mistakes:”

W1_Ql=Q_conv “Ignoring radiation”

W2_Q=Q_rad “ignoring convection”

W3_Q=Q_conv eps*sigma*A*(Ts^4-Tsurr^4) “Using C in radiation calculations”

W4_Q=Q_total/A “not using area”

Chap2-5 Heat Conduction 

Heat is transferred steadily through a 0.15-m thick 3 m by 5 m wall whose thermal conductivity is 1.2 W/m.∞C. The inner and outer surface temperatures of the wall are measured to be 18∞C to 4∞C. The rate of heat conduction through the wall is

(a) 112 W (b) 3360 W (c)  2640 W (d) 38 W (e) 1680 W

Answer  (e) 1680 W

Solution Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 

A=3*5 “m^2”

L=0.15 “m”

T1=18 “C”

T2=4 “C”

k=1.2  “W/m.C”

Q=k*A*(T1-T2)/L “W”

“Some Wrong Solutions with Common Mistakes:”

W1_Q=k*(T1-T2)/L “Not using area”

W2_Q=k*2*A*(T1-T2)/L  “Using areas of both surfaces”

W3_Q=k*A*(T1 T2)/L  “Adding temperatures instead of subtracting”

W4_Q=k*A*L*(T1-T2) “Multiplying by thickness instead of dividing by it”

Topic: Test Bank for Thermodynamics: An Engineering Approach, 8th Edition by Yunus A. Çengel and Michael A. Boles (SI Units)

The Test Bank for “Thermodynamics: An Engineering Approach, 8th Edition” by Yunus A. Çengel and Michael A. Boles, adapted for SI units, is a comprehensive assessment resource designed to support educators in evaluating students’ understanding of the fundamental principles of thermodynamics within an engineering context. This test bank aligns with the detailed and methodical approach presented in the textbook, which is widely respected for its clarity, real-world application, and rigorous treatment of thermodynamic concepts.

Key Features:

1. Comprehensive Coverage of Thermodynamic Principles:
   • The test bank thoroughly covers the key principles of thermodynamics as outlined in the textbook, including the laws of thermodynamics, energy analysis, entropy, and exergy, along with various thermodynamic cycles. Each question is crafted to ensure that students grasp the core concepts essential for engineering applications.
2. Variety of Question Types:
   • The test bank includes a range of question types such as multiple-choice, true/false, short answer, and problem-solving questions. This variety ensures that students are assessed not only on their theoretical knowledge but also on their ability to apply concepts to solve practical engineering problems.
3. Real-World Engineering Applications:
   • Reflecting the textbook’s focus on real-world applications, the test bank includes questions that require students to apply thermodynamic principles to solve problems encountered in engineering practice. These problems often involve the analysis of real systems such as power plants, refrigerators, and engines, making the learning process more relevant and engaging.
4. Focus on Problem-Solving Skills:
   • A significant portion of the test bank is dedicated to problem-solving questions that challenge students to apply their knowledge in practical scenarios. These questions typically involve calculations and the use of thermodynamic tables, reinforcing students’ ability to approach and solve complex engineering problems.
5. SI Unit Consistency:
   • All questions and problems in the test bank are presented using SI units, ensuring consistency with the textbook and helping students develop familiarity with the metric system, which is standard in engineering practice worldwide.
6. Conceptual Understanding and Critical Thinking:
   • The test bank emphasizes not just rote memorization but also deep conceptual understanding and critical thinking. Questions are designed to test students’ grasp of the fundamental concepts and their ability to analyze and interpret thermodynamic data effectively.
7. Integration of Diagrams and Tables:
   • The test bank makes extensive use of diagrams, tables, and charts, similar to those found in the textbook. These visual aids are integral to understanding and solving thermodynamic problems, helping students to visualize complex systems and processes.
8. Customizable for Different Learning Levels:
   • Instructors can easily adapt the test bank to suit different levels of learning, from introductory courses to more advanced engineering classes. This flexibility makes the test bank a versatile tool that can be used across various educational settings.

Content Areas Covered:

• Basic Concepts of Thermodynamics:
  • Questions cover foundational topics such as the definition of thermodynamics, properties of pure substances, the first and second laws of thermodynamics, and the concept of state, process, and cycle.
• Energy, Work, and Heat:
  • This section tests students’ understanding of energy interactions, including work and heat transfer, and the application of the first law of thermodynamics to closed and open systems.
• Properties of Pure Substances:
  • Students are assessed on their ability to use thermodynamic tables and charts to determine the properties of pure substances, such as water and refrigerants, in different phases.
• The First and Second Laws of Thermodynamics:
  • These sections focus on energy conservation (first law) and the concepts of entropy and irreversibility (second law), with questions requiring both conceptual explanations and numerical problem-solving.
• Thermodynamic Cycles:
  • The test bank includes questions on the analysis of various thermodynamic cycles, such as the Carnot, Rankine, and refrigeration cycles, assessing students’ ability to evaluate the performance and efficiency of these cycles.
• Exergy Analysis:
  • Advanced questions are included on the topic of exergy, challenging students to analyze systems based on the concept of exergy and to identify and minimize losses in energy conversion processes.
• Heat Transfer:
  • While not the primary focus, the test bank also touches on heat transfer methods (conduction, convection, radiation) as they relate to thermodynamic systems, integrating these concepts into problem-solving questions.

Conclusion:

The Test Bank for “Thermodynamics: An Engineering Approach, 8th Edition” (SI Units) is an essential resource for instructors aiming to thoroughly assess their students’ understanding of thermodynamics in an engineering context. By offering a wide range of question types that emphasize both theoretical knowledge and practical problem-solving skills, this test bank ensures that students are well-prepared to apply thermodynamic principles in real-world engineering situations. Its comprehensive coverage, alignment with the textbook, and focus on critical thinking make it an invaluable tool in the education of future engineers.