Solved question paper for EME May-2018 (B-TECH 1st-2nd)
Solved Question Paper
Elements of mechanical engineering May-2018
PTU • B-TECH • Mechanical Engineering • 1st-2nd • May-2018
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-
What is meant by thermodynamic equilibrium? How does it differ from thermal equilibrium?Short Answer 2 Marks May-2018 • PTU B-TECH
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Dec 2019 Define thermodynamic equilibrium.
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Dec 2016 What do you understand by thermodynamic equilibrium?
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May 2013 Explain the concept of thermodynamic equilibrium.
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May 2009 Discuss the concept of thermal equilibrium.
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Dec 2008 What is meant by thermodynamic equilibrium?
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What is significance of ∫ pdv in a non-flow system?Short Answer 2 Marks May-2018 • PTU B-TECH
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Differentiate between pv and pdv and give examples of the inclusion of these terms in energy equation.Short Answer 2 Marks May-2018 • PTU B-TECH
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Why Carnot cycle cannot be used practically?Short Answer 2 Marks May-2018 • PTU B-TECH
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Dec 2011 Why is the Carnot cycle not suitable as an ideal cycle for all power producing cycle devices?
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What does the principle of increase of entropy specify?Short Answer 2 Marks May-2018 • PTU B-TECH
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May 2010 What is entropy principle?
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List the assumptions made in the analysis of air standard cycles.Short Answer 2 Marks May-2018 • PTU B-TECH
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What is the function of compression and oil control rings provided on the piston of an IC engine?Short Answer 2 Marks May-2018 • PTU B-TECH
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May 2012 What is function of piston rings in an internal combustion engine?
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State the condition of reversibility and self-locking of a machine.Short Answer 2 Marks May-2018 • PTU B-TECH
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A composite bar constituting of iron and copper in parallel is heated. What would be the nature of the thermal stresses induced in the two bars?Short Answer 2 Marks May-2018 • PTU B-TECH
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Define resilience, proof resilience and modulus of resilience.Short Answer 2 Marks May-2018 • PTU B-TECH
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May 2014 Define the following: i) Resilience, ii) Proof resilience, iii) Modulus of resilience.
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May 2012 Define resilience, proof resilience and modulus of resilience.
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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 pV1.25 = Constant. The initial density of air is 1.2 kg/m3. Find the work involved in the compression process.Long Answer 4 Marks May-2018 • PTU B-TECH
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Dec 2016 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.
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What is the concept of continuum? How density and pressure are defined using this concept?Short Answer 4 Marks May-2018 • PTU B-TECH
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Dec 2016 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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A 0.2 m3 of a gas at 400 kPa and 127°C is contained in a cylinder. A reversible adiabatic expansion takes place to a pressure of 100 kPa. The gas is then heated by an isobaric process till the enthalpy increase is 72 kJ. Find the net work done.Long Answer May-2018 • PTU B-TECH
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A 0.2 m3 of a gas at 400 kPa and 127°C is contained in a cylinder. A reversible adiabatic expansion takes place to a pressure of 100 kPa. The gas is then heated by an isobaric process till the enthalpy increase is 72 kJ. Find the index of expansion if the above processes are replaced by a single reversible polytropic process giving the same work between the same initial and final states.Long Answer May-2018 • PTU B-TECH
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Make an energy analysis of a centrifugal pump.Short Answer 2 Marks May-2018 • PTU B-TECH
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May 2018 Make an energy analysis of a centrifugal pump.
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Dec 2014 Make an energy analysis of a centrifugal pump.
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A centrifugal pump delivers 50 kg of water per second. The inlet and outlet pressures are 1 bar and 4.2 bar respectively. The suction is 2.2 m below the centre of the pump and delivery is 8.5 m above the centre of the pump. The suction and delivery pipe diameters are 20 cm and 10 cm respectively. Find the capacity of electric motor to run the pump.Long Answer 6 Marks May-2018 • PTU B-TECH
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May 2010 The centrifugal pump delivers 50 kg of water per second. The inlet and outlet pressures are 1 bar and 4.2 bar respectively. The suction is 2.2 m below the centre of the pump and delivery is 8.5 m above the centre of the pump. The suction and delivery pipe diameters are 20 cm and 10 cm respectively. Determine the capacity of the electric motor to run the pump.
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May 2009 A centrifugal pump delivers 2750 kg of water per minute from initial pressure of 0.8 bar absolute to a final pressure of 3.8 bar absolute. The suction is 2 m below and delivery is 5 m above the centre of pump. If the suction and delivery pipes are of 15 cm and 10 cm diameter respectively, make calculations for power required to run the pump. Density of water: 1000 kg/m3.
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Derive an expression for the efficiency of a heat engine. What is the normal range of efficiency of heat engine?Long Answer 3 Marks May-2018 • PTU B-TECH
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Which is more effective way to increase the efficiency of a Carnot heat engine: to increase the source temperature T1, while the sink temperature T2 is held constant, or to decrease the sink temperature by the same amount while the source temperature is held constant? How this result would be affected in case of a Carnot heat pump?Long Answer 5 Marks May-2018 • PTU B-TECH
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May 2011 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.
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In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.Long Answer May-2018 • PTU B-TECH
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.
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May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.
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Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4
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Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.
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Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
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In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.Long Answer May-2018 • PTU B-TECH
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.
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May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.
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Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4
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Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.
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Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
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In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.Long Answer May-2018 • PTU B-TECH
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.
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May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.
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Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4
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Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.
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Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
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In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the thermal efficiency.Long Answer May-2018 • PTU B-TECH
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the compression ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the maximum temperature in the cycle.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the work ratio.
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May 2018 In an air standard Otto cycle the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate the thermal efficiency.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the heat supplied per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the work done per kg of air.
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May 2018 In an air standard Otto cycle the compression ratio is 10, the compression begins at 38°C, 1 bar, and the maximum temperature of the cycle is 1060°C. Determine the maximum pressure of the cycle.
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May 2017 An engine working on otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 10^5 N/m^2, Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, take γ = 1.4.
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Dec 2017 An engine is working on OTTO cycle. The pressure and temperature at the beginning of compression stroke are 1 bar and 300 K and the temperature at the end of compression stroke is 600 K. If the temperature at the end of constant volume heat addition process is 1800 K, calculate the air standard efficiency, heat addition per kg of air and heat rejected per kg of air. Assume γ = 1.4, Cv = 0.751 J/kg K.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression = 1 × 105 N/m2. Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine. Take y = 1.4.
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May 2015 An engine working on Otto cycle has the following conditions: Pressure at the beginning of compression =1 × 10^5 N/m^2 Pressure at the end of compression = 10 bar. Calculate the air standard efficiency of the engine, Take y = 1.4
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Dec 2014 In an air standard Otto cycle, the pressure and temperature at the start of compression is 1 bar and 310 K. The pressure at the end of compression is 28 bar and at the end of heat addition is 75 bar. Calculate: (a) the compression ratio, (b) the maximum temperature in the cycle, (c) work ratio, (d) thermal efficiency.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the thermal efficiency of the cycle.
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May 2008 An air standard Otto cycle operates with a compression ratio of 8.5:1. At the beginning of the compression the air is at 1 bar and 32°C and during the heat addition process the pressure is tripled. Calculate the efficiency of the Carnot engine operating between the same overall temperature limits.
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Dec 2008 An air standard Otto cycle has compression ratio 10, the compression begins at 37.8°C, 1 bar and maximum temperature of the cycle is 1050°C. Determine: (a) the heat supplied per kg of air, (b) the work done per kg of air, (c) the maximum pressure of the cycle, and (d) the thermal efficiency.
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Prove that heat absorbed during a process is approximately equal to the change in entropy multiplied by the mean absolute temperature during process.Long Answer 4 Marks May-2018 • PTU B-TECH
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Show that whenever a system executes a complete cyclic process, ∮ is less than zero or in the limit is equal to zero.Long Answer 4 Marks May-2018 • PTU B-TECH
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A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate σx and σy.Long Answer May-2018 • PTU B-TECH
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in thickness of the plate.
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in volume of the plate.
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A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in thickness of the plate.Short Answer May-2018 • PTU B-TECH
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate σx and σy.
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in volume of the plate.
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A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in volume of the plate.Short Answer May-2018 • PTU B-TECH
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate σx and σy.
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May 2018 A rectangular steel plate 100 cm long, 40 cm wide and 2 cm thick is subjected to bi-axial stress σx and σy acting along length and width respectively. If the increase in length is 0.6 mm and the increase in width is 0.09 mm, calculate the change in thickness of the plate.
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Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Diesel engine. Describe briefly the factors which account for deviations between these plots.Long Answer 4 Marks May-2018 • PTU B-TECH
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May 2018 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.
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May 2014 Discuss the difference between theoretical and actual p–V diagrams for four stroke S.I. and C.I. engines.
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Dec 2014 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke petrol engine. Describe briefly the factors which account for deviations between these plots.
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May 2013 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.
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Dec 2012 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Diesel engine. Describe briefly the factors which account for deviations between these plots.
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Dec 2012 Give a neat sketch of the theoretical and actual pV diagrams for a four stroke Petrol engine. Describe briefly the factors which account for deviations between these plots.
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Dec 2011 Discuss the difference between theoretical and actual p–V diagrams for two stroke S.I. and C.I. engines.
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Sketch and briefly explain any two inversions of a double slider crank chain.Long Answer 4 Marks May-2018 • PTU B-TECH
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May 2011 Discuss various inversions of double slider crank chain mechanism.
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Dec 2010 Discuss the various inversion of double slider crank chain mechanism.
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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?
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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?
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