Solved question paper for EME Dec-2016 (B-TECH 1st-2nd)
Solved Question Paper
Elements of mechanical engineering Dec-2016
PTU • B-TECH • Mechanical Engineering • 1st-2nd • Dec-2016
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-
Explain the difference between temperature, heat and internal energy.Short Answer 2 Marks Dec-2016 • PTU B-TECH
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May 2019 Distinguish between internal energy and enthalpy.
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May 2018 Differentiate between temperature, heat and internal energy.
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Dec 2014 Differentiate between temperature, heat and internal energy.
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Dec 2012 Differentiate between temperature, heat and internal energy.
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May 2010 Differentiate between temperature, heat and internal energy.
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State the basic assumptions of steady flow energy equation.Short Answer 2 Marks Dec-2016 • PTU B-TECH
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Dec 2023 Derive steady flow energy equation for a single stream of fluid entering and leaving the control volume.
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May 2019 Derive steady flow energy equation for a single stream of fluid entering and leaving the control volume.
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May 2016 Give the differential form of the steady flow energy equation.
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Dec 2009 Explain and derive steady flow energy equation.
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May 2007 State and write the steady flow energy equation.
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Why does the enthalpy of an ideal gas depend upon temperature only?Short Answer 2 Marks Dec-2016 • PTU B-TECH
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May 2008 Define enthalpy, why does the enthalpy of an ideal gas depend only on temperature? Discuss.
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State Carnot theorem for an engine and a refrigerator.Short Answer 2 Marks Dec-2016 • PTU B-TECH
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May 2018 State the Carnot Theorem in the context of a heat pump / refrigerator.
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Dec 2014 State the Carnot Theorem in the context of a heat pump/refrigerator.
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How does the Second law of thermodynamics overcome the limitation of the First law?Short Answer 2 Marks Dec-2016 • PTU B-TECH
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Dec 2009 What are the limitations of first law of thermodynamics?
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May 2007 What are the limitations of first law of thermodynamics?
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May 2007 How second law of thermodynamics overcomes the limitation of first law?
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What is the function of crank shaft and flywheel in an IC engine?Short Answer 2 Marks Dec-2016 • PTU B-TECH
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May 2014 State the purpose of piston rings and crank shaft in an I.C. engine.
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Dec 2011 State the purpose of cam shaft and piston rings in an I.C. engine?
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Dec 2011 State the purpose of cam shaft and flywheel in an I.C. engine.
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What is air standard efficiency? Write its expression for diesel cycle.Short Answer 2 Marks Dec-2016 • 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 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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May 2012 Derive an expression for efficiency and mean effective pressure for a Diesel cycle.
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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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What is mild steel? How is it different from cast iron and wrought iron?Short Answer 2 Marks Dec-2016 • PTU B-TECH
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How does stainless steel become stainless?Short Answer 2 Marks Dec-2016 • PTU B-TECH
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Define centre of gravity and centroid.Short Answer 2 Marks Dec-2016 • PTU B-TECH
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Dec 2019 Differentiate between centroid and centre of gravity.
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A mass of 1.5 kg of air is compressed in a quasi-static process from 1.1 bar to 10 bar according to the law pV^1.25 = Constant. The initial density of air is 1.2 kg/m^3. Find the work involved in the compression process.Long Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2018 A mass of 1.5 kg of air is compressed in a quasi-static process from 1.1 bar to 10 bar according to the law pV1.25 = Constant. The initial density of air is 1.2 kg/m3. Find the work involved in the compression process.
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What is the concept of continuum? How density and pressure are defined using this concept?Short Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2018 What is the concept of continuum? How density and pressure are defined using this concept?
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May 2013 What is the concept of continuum? How will you define density and pressure using this concept?
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Dec 2012 What is the concept of continuum? How density and pressure are defined using this concept.
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Steam enters a nozzle at a pressure of 7 bar and 205°C (i.e. initial enthalpy 2850 kJ/kg) and leaves at a pressure of 1.5 bar. The initial velocity of steam at the entrance is 40 m/s and exit velocity from the nozzle is 700 m/s. The mass flow rate through the nozzle is 1400 kg/hr. The heat loss from the nozzle is 11705 kJ/hr. Determine the final enthalpy of steam and the nozzle exit area, if the specific volume is 1.24 m^3/kg.Long Answer 8 Marks Dec-2016 • PTU B-TECH
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Prove that the efficiency of an engine working on a reversible cycle depends only on the temperature of source and sink and is independent of the working fluid.Long Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2016 Prove that the efficiency of an engine working on a reversible cycle depends only on the temperature of source and sink and is independent of the working fluid.
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Comment on the validity of the statement: All reversible engines operating between the same two thermal reservoirs have the same efficiency.Short Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2014 Verify the statement “The efficiency of an irreversible engine is always less than the efficiency of reversible one operating between the same two thermal reservoirs”.
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Dec 2012 Comment on the validity of the statement: “All reversible engines operating between the same two thermal reservoirs have the same efficiency.”
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Define entropy and show that for an irreversible process, dS > δQ/T.Long Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2014 Define inequality of Clausius and entropy of a system. Show that for an irreversible process ds > dQ/T.
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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.Short Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2012 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.
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Derive an expression for efficiency and mean effective pressure of Otto cycle.Long Answer 8 Marks Dec-2016 • PTU B-TECH
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Dec 2023 Draw Otto cycle and derive its air standard efficiency and mean effective pressure.
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Dec 2018 Derive an expression for the air standard thermal efficiency of Otto cycle.
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May 2017 Derive the expression for air standard efficiency for Otto cycle. Also draw its PV and T-S diagram.
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Dec 2010 Derive an expression for the air standard efficiency and mean effective pressure of an Otto cycle. State the assumptions made.
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May 2007 Derive the expression for the air standard efficiency for otto cycle.
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Find the moment of inertia of a circle about its diametrical axis.Short Answer 4 Marks Dec-2016 • 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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May 2012 Find the moment of inertia of a semi circle about its diametrical axis.
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Find the centroid of a quarter of a circle.Short Answer 4 Marks Dec-2016 • PTU B-TECH
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Dec 2023 b) Find the centroid of a quarter of a circle.
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May 2012 Find the centroid of a quarter of a circle.
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Discuss the effect of following alloying elements in steel: Chromium, Nickel, Tungsten, Sulphur.Short Answer 4 Marks Dec-2016 • PTU B-TECH
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What are ceramics? Explain classification of ceramics. Also write properties and application of ceramics.Long Answer 4 Marks Dec-2016 • PTU B-TECH
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Dec 2012 What are ceramic materials? Name some of important ceramic materials. State advantages of ceramic materials.
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Explain briefly particle-reinforced, fibre-reinforced and structural composite.Short Answer 4 Marks Dec-2016 • PTU B-TECH
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May 2018 Explain briefly, particle reinforced, fiber reinforced and structural composites.
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Dec 2014 Explain briefly particle reinforced, fiber reinforced and structural composites.
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A diesel engine takes in air at 1 bar and 27°C. The compression and expansion ratios are 18 and 6 respectively. Estimate the quantity of heat energy added, rejected and the efficiency of the cycle. Take γ = 1.4, cp = 1.005 kJ/kg-K, and cv = 0.717 kJ/kg-K.Long Answer 4 Marks Dec-2016 • PTU B-TECH
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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.