Solved question paper for EME May-2012 (B-TECH 1st-2nd)
Solved Question Paper
Elements of mechanical engineering May-2012
PTU • B-TECH • Mechanical Engineering • 1st-2nd • May-2012
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.
PART-A
1. Basic Concepts of Thermodynamics (08)
Definition of thermodynamic: Need to study thermodynamics; Application areas of thermodynamic; Difference between Microscopic (or, Statistical) thermodynamics and Macroscopic(or, Classical) thermodynamics; Brief concept of continuum; Thermodynamic System : definition, types (Open, Closed and Isolated) and their examples; Thermodynamic System Boundary : definition, types and their examples; Surroundings; Control(fixed) mass and Control Volume concept and their example ; Thermodynamic State; Thermodynamic Property: definition, types citing their examples; condition for any quantity to be a property; State postulate; Thermodynamic equilibrium (which includes Thermal, Mechanical and Chemical equilibrium etc.); Thermodynamic path; Thermodynamic process: definition, concept of reversible process, quasi-static (or, quasi-equilibrium) process, irreversible process, conditions for reversibility and how these are met with, non-flow processes and flow processes, method of representation of reversible and irreversible process on property diagrams; Cyclic process; Thermodynamic Cycle: definition and its concept; Energy and its forms (microscopic and macroscopic); Physical insight to internal energy; Energy transfer across system boundary i.e. transient energies (heat and work); Difference between heat and work; Sign conventions for heat and work interactions; heat and work as path functions; Equality of Temperature and Zeroth law of Thermodynamics.
2. First Law of Thermodynamics and its applications (12)
Definition, essence and corollaries or consequences of first law of Thermodynamics; Expressions for First law of Thermodynamics for a control mass undergoing a Cycle and for process (i.e., a change in state of a control mass) ; Concept of Enthalpy and total energy and differentiation between the two - a thermodynamic property; Compressible and incompressible substances, Specific heats, Difference between Internal Energy and Enthalpy of compressible and incompressible substances; Representation of first law of thermodynamics as rate equation; Analysis of non-flow/ flow process for a control mass undergoing constant volume, constant pressure, constant temperature, adiabatic and polytropic processes; Free Expansion Process and its examples, its representation on Property diagram; Review of concepts of control volume; Expressions of first law of thermodynamics for a control volume (i.e. open system) ; Steady State Steady Flow process and its examples; First law analysis of Steady State Flow process e.g. isochoric, isobaric, isothermal, isentropic and polytropic process; Throttling process and its applications; Flow energy or inertial energy of flowing fluids or, Energy transport by mass; Application of Steady State Flow Energy Equation to various engineering devices.
3. Second Law of Thermodynamics (16)
Limitations of first law of thermodynamics; and how 2nd law is fully able to explain away and thus overcome those shortcomings of Ist law; Thermal Reservoirs, source and sink (Low temperature and high temperatures); Heat Engine, Heat Pump and Refrigerator: definitions, working, efficiency/performance and their real life examples. Justification as to why the actual efficiency of Heat Pump and Refrigerator shall also be ≤ 100% though on the face of it seems to be more than 100%; Various statements of Second Law of Thermodynamics and their equivalence; Philosophy of Carnot cycle and its consequences viz. how each of the individual four processes constituting the cycle contribute in optimizing the output and efficiency of the cycle; Carnot Engine, Carnot Refrigerator and Carnot Heat Pump: definitions, working, efficiency/performance and Limitations of the cycle; Carnot theorem for heat engines, refrigerators and heat pumps; derivation of Carnot efficiency/COP (which seems to be more than 100%); Thermodynamic Temperature Scale; Clausius theorem and Inequality; Philosophy and concept of entropy; Entropy changes during various processes; Temperature - Entropy Chart and representation of various processes on it; Principle of Increase of Entropy; Applications of Entropy Principle; Quality of Energy viz. high and low grade energies; Degradation of Energy; Third Law of Thermodynamics.
PART-B
4. Gas Power Cycles (12)
Introduction; Concept and philosophy of Air Standard Cycle alongwith associated assumptions and advantages; Air Standard Efficiency; Nomenclature of reciprocating piston-cylinder arrangement with basic definitions such as swept volume, clearance volume, compression ratio, mean effective pressure etc; Otto Cycle (or constant volume heat addition cycle), Diesel cycle (or constant pressure heat addition cycle) and Dual cycle (Mixed or Composite or Limited Pressure cycle) with their representation on P-V and T-S charts, their Air-standard (thermal) Efficiencies; Brayton Cycle, Comparison of Otto, Diesel and Dual cycle under some defined similar parametric conditions; Introduction to heat engines; Merits of I.C. Engines and their important applications, Classification and constructional features of I.C. Engines; working of two stroke and four stroke Petrol and Diesel engines and their comparison.
5. Engineering Materials (05)
Materials and Civilization, Materials and Engineering, Classification of Engineering Materials, Mechanical Properties of Materials: elasticity, plasticity, strength, ductility, brittleness, melleability, toughness, resilience, hardness, machinability, formability, weldability. Properties, Composition, and Industrial Applications of materials: metals (ferrous- cast iron, tool steels, stainless steels and non ferrous- Aluminum, brass, bronze ), polymers (natural and synthetic , thermoplastic and thermosetting), ceramics (glass, optical fibre glass, cements), composites ( fibre reinforced, metal matrix), smart materials (piezoelectric, shape memory, thermochromic, photochromic, magnetorheological), Conductors, Semiconductors and insulators, Organic and Inorganic materials. Selection of materials for engineering applications.
6. Centroid, Centre of Gravity and Moment of Inertia: (08)
Difference between centre of gravity and centroid. Determination of position of centroid of plane geometric figures of I, U, H, L, T, C, Circular and Triangular Sections. Centroid of Composite Areas. Determination of position of Centre of Gravity (CG) of regular solids viz. Right Circular Cone, Solid Hemisphere, thin Hollow Hemisphere. Area moment of inertia & mass moment of inertia, Polar moment of inertia, Parallel axes Theorem (or transfer formula), Perpendicular axes Theorem, Radius of gyration, determination of area Moment of Inertia of I, U, H, L, T, C, Circular and Triangular Sections along various axes. Mass moment of Inertia of Circular Ring, Disc, Cylinder, Sphere and Cone about their axis of symmetry and other axes.
Solved Questions
Solved-
Show that work is a path function.Short Answer 2 Marks May-2012 • PTU B-TECH
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What is a free expansion process? What are its characteristics?Short Answer 2 Marks May-2012 • PTU B-TECH
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Differentiate between a heat pump and a refrigerator.Short Answer 2 Marks May-2012 • PTU B-TECH
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Dec 2023 Distinguish between heat pump and refrigerator.
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May 2015 Differentiate between heat engine, heat pump and refrigerator.
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Draw the variation of thermal efficiency against compression ratio of an Otto cycle.Short Answer 2 Marks May-2012 • PTU B-TECH
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What is function of piston rings in an internal combustion engine?Short Answer 2 Marks May-2012 • PTU B-TECH
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May 2018 What is the function of compression and oil control rings provided on the piston of an IC engine?
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Differentiate between brass and bronze.Short Answer 2 Marks May-2012 • PTU B-TECH
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What are technological properties of materials?Short Answer 2 Marks May-2012 • PTU B-TECH
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Dec 2017 Explain any five properties of engineering materials.
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May 2013 Explain different types of technological properties of materials.
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What is moment of inertia and why is it called second moment of area?Short Answer 2 Marks May-2012 • PTU B-TECH
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Differentiate between thermoplastic and thermosetting plastic.Short Answer 2 Marks May-2012 • PTU B-TECH
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May 2020 What is the difference between thermoplastic and thermosetting materials?
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Dec 2020 What is the difference between thermoplastic and thermosetting materials?
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May 2017 Differentiate between thermoplastics and thermosetting plastics.
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An inventor of heat engine claims that his engine is 75% efficient which receives heat at 100°C and rejects at 20°C. How do you rate his claim?Short Answer 2 Marks May-2012 • PTU B-TECH
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A mass of gas is compressed in a quasi-static process from 80kPa, 0.1m3 to 0.4 MPa, 0.03m3. Assume that pressure and volume are related by pV n = Constant. Find the work done by the gas system.Short Answer 5 Marks May-2012 • PTU B-TECH
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Define control volume and control surface. How does control volume differ from an open system?Short Answer 3 Marks May-2012 • PTU B-TECH
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Dec 2012 How does a control volume differ from a system?
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Write down the general steady flow energy equation and deduce it for a nozzle, stating the assumptions taken.Short Answer 2 Marks May-2012 • PTU B-TECH
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May 2020 Write down the general energy equations for a steady flow system and simplify it for a steam nozzle.
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Dec 2020 Write down the general energy equations for steady flow system and simplify when applied to a steam nozzle.
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Steam enters a steam turbine at 5 m elevation, at a velocity of 30 m/s, enthalpy 2950 kJ/kg. At exit, the velocity is 600 m/s, enthalpy 2200 kJ/kg and elevation 2 m. 75 kJ/kg of heat is lost to the surroundings. Calculate the work output of the turbine.Short Answer 6 Marks May-2012 • PTU B-TECH
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Dec 2012 Steam enters a steam turbine at 5m elevation, at a velocity of 30m/s, enthalpy 2950 kJ/kg. At exit the velocity is 600 m/s, enthalpy 2200 kJ/kg and elevation 2m, 75 kJ/kg of heat is lost to the surroundings. Calculate the work output of the turbine.
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Dec 2011 The mass rate of flow into a steam turbine is 1.5 kg/s, and the heat transfer from the turbine is 8.5 kW. The following data are known for the steam entering and leaving the turbine: Inlet enthalpy 3137.0 kJ/kg, velocity 50 m/s, elevation above reference plane 6 m; Outlet enthalpy 2675.5 kJ/kg, velocity 200 m/s, elevation above reference plane 3 m. Find the power output of the turbine.
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State and prove Clausius inequality.Long Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2023 b) State and prove Clausius inequality.
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May 2016 Explain the concept of Clausius Inequality.
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Dec 2016 What is Clausius inequality?
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Dec 2011 State and prove Clausius inequality.
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In a refrigerator, heat is transferred from a lower temperature to higher temperature. Is this a violation of second law of thermodynamics? Explain.Short Answer 4 Marks May-2012 • PTU B-TECH
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Define the term entropy. Show that entropy is a property of the system.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2023 a) Define entropy and prove that it is property of a system.
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May 2014 Define the term entropy. Show that entropy is a property of the system.
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Heat flows from a hot reservoir at 800 K to another reservoir at 250 K. If the entropy change of overall process is 4.25 kJ/K, make calculations for the heat flowing out of the high temperature reservoir.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2016 Heat flows from a reservoir at 800 K to another reservoir at 250 K. If entropy change of the hot reservoir is –4 kJ/K, determine the entropy change of the cold reservoir.
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Derive an expression for efficiency and mean effective pressure for a Diesel cycle.Long Answer 8 Marks May-2012 • PTU B-TECH
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Dec 2020 Derive the expression for the efficiency of the Diesel cycle.
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Dec 2016 What is air standard efficiency? Write its expression for diesel cycle.
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Dec 2016 Derive the expression for the ideal efficiency of Diesel cycle.
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May 2015 Derive the efficiency equation for Diesel cycle.
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Dec 2014 Write down the expression for air standard efficiency for a diesel engine?
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May 2013 Derive an expression for the air standard efficiency and mean effective pressure of a Diesel cycle. State the assumptions made.
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Dec 2011 Derive an expression for mean effective pressure of diesel cycle.
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Dec 2007 What is air standard efficiency? Write its expression for diesel cycle.
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Find the moment of inertia of a semi circle about its diametrical axis.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2023 a) Find the moment of inertial of a semi circle about its diametrical axis.
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Dec 2016 Find the moment of inertia of a circle about its diametrical axis.
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Find the centroid of a quarter of a circle.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2023 b) Find the centroid of a quarter of a circle.
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Dec 2016 Find the centroid of a quarter of a circle.
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Discuss the composition, specific properties and main applications of Mild steel.Long Answer 6 Marks May-2012 • PTU B-TECH
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May 2016 Give composition and uses of high carbon steel and high speed steel.
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May 2012 Discuss the composition, specific properties and main applications of High carbon steel.
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May 2012 Discuss the composition, specific properties and main applications of High speed steel.
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May 2012 Discuss the composition, specific properties and main applications of Stainless steel.
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Discuss the composition, specific properties and main applications of High carbon steel.Long Answer 6 Marks May-2012 • PTU B-TECH
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May 2016 Give composition and uses of high carbon steel and high speed steel.
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May 2012 Discuss the composition, specific properties and main applications of Mild steel.
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May 2012 Discuss the composition, specific properties and main applications of High speed steel.
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May 2012 Discuss the composition, specific properties and main applications of Stainless steel.
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Discuss the composition, specific properties and main applications of High speed steel.Long Answer 6 Marks May-2012 • PTU B-TECH
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May 2016 Give composition and uses of high carbon steel and high speed steel.
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May 2012 Discuss the composition, specific properties and main applications of Mild steel.
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May 2012 Discuss the composition, specific properties and main applications of High carbon steel.
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May 2012 Discuss the composition, specific properties and main applications of Stainless steel.
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Discuss the composition, specific properties and main applications of Stainless steel.Long Answer 6 Marks May-2012 • PTU B-TECH
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May 2016 Give composition and uses of high carbon steel and high speed steel.
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May 2012 Discuss the composition, specific properties and main applications of Mild steel.
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May 2012 Discuss the composition, specific properties and main applications of High carbon steel.
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May 2012 Discuss the composition, specific properties and main applications of High speed steel.
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State Thermochromic effect.Short Answer 2 Marks May-2012 • PTU B-TECH
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May 2012 State Photochromic effect.
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State Photochromic effect.Short Answer 2 Marks May-2012 • PTU B-TECH
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May 2012 State Thermochromic effect.
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A gas engine working on Otto cycle has cylinder bore (diameter) = 220 mm; stroke length = 300 mm, clearance volume = 1600 cm3. Find the air standard efficiency. Take γ = 1.4.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2014 A gas engine working on otto cycle has: Cylinder borer (diameter) = 220 mm; Stroke length = 300 mm, Clearance volume = 1600 cm3. Find the air standard efficiency (Take y =1.4).
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List the major factors affecting the selection of materials.Short Answer 4 Marks May-2012 • PTU B-TECH
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Dec 2023 List the major factors affecting the selection of materials.
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May 2019 Enumerate the criteria for selection of materials for engineering applications.
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FAQ
Frequently Asked Questions
Answers about this subject, solved papers, and preparation.
01 Where can I find elements of mechanical engineering previous year question papers for Bachelor of Technology, 1st-2nd semester?
This page lists elements of mechanical engineering question papers uploaded for Punjab Technical University Bachelor of Technology, 1st-2nd semester, organized for subject-wise browsing where available.
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.