Solved question paper for EME May-2011 (B-TECH 1st-2nd)

Solved Question Paper

Elements of mechanical engineering May-2011

PTU • B-TECH • Mechanical Engineering • 1st-2nd • May-2011

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. With same compression ratio, an engine working on Dual, Diesel or Otto cycle is most efficient. Select the correct cycle.
    MCQ 2 Marks May-2011 • PTU B-TECH
  2. Starting from the same initial state, plot constant volume and constant pressure heat addition processes on the T-S coordinates along with arrow-heads indicating the direction of the processes, and identify these two processes on the T-S chart.
    Short Answer 2 Marks May-2011 • PTU B-TECH
  3. What is the fundamental and basic difference between the terms enthalpy and total energy associated with the mass of a thermodynamic medium?
    Short Answer 2 Marks May-2011 • PTU B-TECH
  4. Justify by assigning some numerical values, through a practical example, that dQ is not equal to dW for an irreversible heat exchange process; for example, by considering irreversible heat addition to a heat engine.
    Short Answer 2 Marks May-2011 • PTU B-TECH
  5. Starting from the same initial state, plot reversible and irreversible adiabatic expansion processes on T-S coordinates along with arrow-heads indicating the direction of the processes. Show the area which represents the fraction of energy that becomes unavailable during the irreversible process.
    Short Answer 2 Marks May-2011 • PTU B-TECH
  6. Can the COP of a refrigerator be greater than, less than, or both greater than as well as less than unity? Select the correct answer, and justify your reply by assigning numerical values to the cooling effect and the compressor work using a simple real-life practical example.
    MCQ 2 Marks May-2011 • PTU B-TECH
  7. Can throttling process be plotted on p-v coordinates? Give answer in YES or NO and give reasons for the same.
    True / False 2 Marks May-2011 • PTU B-TECH
  8. Super-impose a Carnot cycle on a Diesel cycle plotted on the T-S coordinates, such that the end-states representing the lowest and highest temperatures for the two cycles are coinciding with each other. Illustrate with the aid of T-S coordinates that the Diesel cycle operating between the same lowest and highest temperature limits will be less efficient than the corresponding Carnot cycle.
    Short Answer 2 Marks May-2011 • PTU B-TECH
  9. During free expansion process, temperature decreases, increases or remains constant. Select the correct answer.
    MCQ 2 Marks May-2011 • PTU B-TECH
  10. Define temperature stresses and strains.
    Short Answer 2 Marks May-2011 • PTU B-TECH
  11. How enthalpy differs from the term heat transfer? Explain the difference between the two in detail.
    Long Answer May-2011 • PTU B-TECH
  12. One of the essential requirements for accomplishing any reversible expansion process is that there should be complete thermal equilibrium between the system and the thermal reservoir exchanging heat during the process. Justify the above statement by thermodynamic or any other logic.
    Long Answer May-2011 • PTU B-TECH
  13. Is the equation dQ = dU - Vdp valid for a process occurring in an open system, in a closed system, or in both systems? Select the correct answer.
    MCQ May-2011 • PTU B-TECH
  14. The properties of a certain gas are related as follows: E = 196 + 0.718 t and Pv = 0.287 (t + 273), where E is the specific internal energy (kJ/kg), t is in °C, p is pressure in kN/m² and v is specific volume (m³/kg). Determine the two specific heats C_v and C_p for this gas.
    Long Answer May-2011 • PTU B-TECH
  15. Select suitable coordinates for plotting free expansion process and plot it on those coordinates along with an arrow-head indicating the direction of the process.
    Short Answer May-2011 • PTU B-TECH
  16. Air at 1 bar and 7°C is heated at constant volume in a cylinder till its temperature has risen to 821°C. It is then expanded isentropically to 1 bar and subsequently heat is rejected at constant pressure until the temperature is again equal to 7°C. Determine per kg of air: (i) pressure, volume and temperature at the end of each process, (ii) heat supplied to the cycle, (iii) work delivered by the cycle, and (iv) efficiency of the cycle.
    Long Answer May-2011 • PTU B-TECH
  17. An irreversible engine takes 1200 kW from a reservoir at 700 K and develops 200 kW of work when executing complete cycles. The engine rejects heat to two reservoirs at 600 K and 500 K. Determine heat rejected to both the reservoirs. Draw a schematic line sketch for the engine and plot the cycle for this engine on T-S coordinates.
    Long Answer May-2011 • PTU B-TECH
  18. Explain and justify how isothermal heat addition process contributes in optimizing the output and hence efficiency of the Carnot cycle.
    Long Answer May-2011 • PTU B-TECH
  19. Which is the more effective method of increasing the efficiency of a Carnot cycle out of the following two possibilities: (i) by increasing T1 while maintaining T2 constant, or (ii) by decreasing T2 while maintaining T1 constant (T1 > T2)? Arrive at your decision with the help of T-S chart.
    Long Answer May-2011 • PTU B-TECH
  20. In an air standard Brayton cycle, the air enters the compressor at 1 bar and 25°C. The pressure after compression is 3 bar. The temperature at turbine inlet is 650°C. Calculate per kg of air: (a) heat supplied, (b) heat rejected, (c) net work done, (d) temperature of air leaving the turbine, (e) air-standard efficiency of the cycle, and (f) work ratio of the unit.
    Long Answer May-2011 • PTU B-TECH
  21. Write brief notes on differential wheel and axle.
    Short Answer May-2011 • PTU B-TECH
  22. Write brief notes on lifting machines.
    Short Answer May-2011 • PTU B-TECH
  23. Write brief notes on worm and worm wheel.
    Short Answer May-2011 • PTU B-TECH
  24. Make a labeled sketch of the Oldham coupling and list its uses.
    Short Answer May-2011 • PTU B-TECH
  25. Define kinematic link, kinematic pair and kinematic chain.
    Short Answer May-2011 • 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?

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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?

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

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