Solved question paper for EME May-2014 (B-TECH 1st-2nd)

Solved Question Paper

Elements of mechanical engineering May-2014

PTU • B-TECH • Mechanical Engineering • 1st-2nd • May-2014

elements of mechanical engineering previous year question papers on BRpaper are organized for students of Punjab Technical University’s Bachelor of Technology program, 1st-2nd semester. This section makes it easier to browse subject-wise old question papers for elements of mechanical engineering, so students can review how questions are typically framed in past exams and get a sense of the exam pattern. Many students search for elements of mechanical engineering question bank while preparing for exams, and this page is built to support exactly that kind of subject-wise browsing and revision. BRpaper is not the official website of Punjab Technical University or any institution, and it does not publish official notices or academic updates.

Solved Questions

Solved
  1. If the change in energy of a closed system is known for a process between two end states, can you determine whether the energy change was due to work, heat transfer, or some combination of work and heat transfer?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  2. Show how the polytropic exponent n can be evaluated if you know the end state properties (P1, V1) and (P2, V2).
    Short Answer 2 Marks May-2014 • PTU B-TECH
  3. In the absence of any friction and other irreversibilities, can a heat engine have an efficiency of 100 percent? Explain.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  4. In a complete cycle, what is the net change in energy and volume?
    Very Short Answer 2 Marks May-2014 • PTU B-TECH
  5. The entropy of a hot baked potato decreases as it cools. Is this a violation of the increase of entropy principle? Explain.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  6. Ice cubes in a glass of liquid water will eventually melt and all the water approach room temperature. Is this a reversible process? Why?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  7. The moment of inertia of a triangular section of base b and height h about an axis passing through its vertex and parallel to its base is ______ times as that passing through its centre of gravity and parallel to its base.
    Fill in the Blanks 2 Marks May-2014 • PTU B-TECH
  8. State the purpose of piston rings and crank shaft in an I.C. engine.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  9. Name any four mechanical properties of metals and corresponding tests to find them.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  10. What are composites? Name any four along with their applications.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  11. A piston cylinder device contains unit mass of a fluid at 20 atm and 0.04 m3. The fluid is expanded reversibly according to the law pV^1.5 = C until the volume becomes 2 times that of its initial value. The fluid is then cooled reversibly at constant pressure until the piston comes back to its original position. Now, heat is supplied reversibly with the piston locked in position until the pressure rises to the original value of 20 atm. Calculate the net work done by the fluid.
    Long Answer May-2014 • PTU B-TECH
  12. Justify the statement that work and heat are not properties.
    Short Answer May-2014 • PTU B-TECH
  13. Oxygen passes through an adiabatic steady flow compressor at the rate of 1000 kg/h, entering as saturated vapour at 2.5 atm and emerging at 17.5 atm and 175 K. Find the shaft power required per kg of oxygen and the required power of the motor to run the compressor. Treat oxygen as an ideal gas and take y = 1.4.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  14. Prove that the COP of a reversible refrigerator operating between two given temperatures is the maximum.
    Long Answer May-2014 • PTU B-TECH
  15. A reversible engine operates between temperatures T1 and T2 (T1 > T2). The energy rejected from the engine is received by a second reversible engine at the same temperature T2. The second engine rejects energy at temperature T3 (T3 < T2). Show that the temperature T2 is the arithmetic mean of temperatures T1 and T3 if the engine produces the same amount of work output.
    Long Answer May-2014 • PTU B-TECH
  16. Define the term entropy. Show that entropy is a property of the system.
    Long Answer May-2014 • PTU B-TECH
  17. 1 kg of ice at -5°C is exposed to the atmosphere, which is at 20°C. The ice melts, and comes to thermal equilibrium with the surroundings. Determine the entropy increase of the universe. Take Cp(ice) = 2.093 kJ/kg-K and the latent heat of fusion of ice = 334 kJ/kg.
    Long Answer May-2014 • PTU B-TECH
  18. What do you mean by air standard cycles? What are the assumptions for air standard cycles?
    Short Answer May-2014 • PTU B-TECH
  19. An engine working on air standard Otto cycle in which the salient points are 1, 2, 3 and 4 has upper and lower temperature limits T1 and T2. If the maximum work per kg of air is to be done, show that the intermediate temperature T3 = √(T1T2).
    Long Answer May-2014 • PTU B-TECH
  20. Find the centroid of a lamina as shown in figure.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  21. Find the moment of inertia for a triangular lamina about (a) centroidal axis parallel to the base, (b) the base.
    Long Answer May-2014 • PTU B-TECH
  22. Differentiate between: (a) Creep and fatigue, (b) Ductility and malleability, (c) Elastic limit and proportional limit, (d) Yield stress and proof stress.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  23. Briefly describe the selection procedure of materials.
    Short Answer 4 Marks May-2014 • PTU B-TECH
  24. Discuss the difference between theoretical and actual p–V diagrams for four stroke S.I. and C.I. engines.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  25. In an engine based on Carnot cycle 0.6 kg of air is used giving a thermal efficiency of 60 percent. During isothermal expansion the heat transfer is 50 kJ. At the start of isothermal expansion, the pressure is 7 bar and the volume is 0.125 m3. Calculate: (a) the maximum and the minimum temperature for the cycle, (b) volume at the end of isothermal expansion, (c) heat transfer during each of the four processes. Take Cv = 0.718 kJ/kg-K and Cp = 1.005 kJ/kg-K.
    Long Answer 8 Marks May-2014 • PTU B-TECH

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01 Where can I find elements of mechanical engineering previous year question papers for Bachelor of Technology, 1st-2nd semester?

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02 Are these official Punjab Technical University question papers?

BRpaper is not the official website of Punjab Technical University. These papers are shared for reference and revision purposes only and are not official university material.

03 How can previous year elements of mechanical engineering papers help in exam preparation?

Reviewing past papers can help you understand how questions are typically framed, notice commonly repeated topics, and get a sense of the exam pattern before your own exam.

04 What kind of topics does elements of mechanical engineering usually cover?

The question papers here relate to the official elements of mechanical engineering syllabus set by the university for this course and semester.

05 Does this page include a elements of mechanical engineering question bank or solved answers?

This page focuses on providing access to the previous year question papers themselves. A separate question bank or solved answers may not be available for every paper.

06 Can I find papers for other subjects in the same Bachelor of Technology?

Yes, BRpaper organizes papers by university, course, stream, and semester, so you can browse other subjects within the same Punjab Technical University Bachelor of Technology.