UNIQUE CLASSES; JINDAL NAGAR

There is a popular belief that there are two types of study techniques, where as one is for quick and vague learning basically to score easily in the examination. This process is also known as vomiting techniques. Here, before examination students study basically notes and Question answer seried like Quantum books of UP.
The other process is the process of concept building and it needs attentive study with high concentration. It is difficult but it is the process which helps to clear various entrance examinations and qualifying examinations of various PSU jobs as well as jobs in the private sectors
Personally, I was never a believer of the Cramming Process, although I know language problems often force a student to take the help of Cramming. But, to get rid of this tandency, we wanted to establish a learning center near the place where students reside. Partially it will reduce their travelling time and get more time to study.
As per our requirement Jindal Nagar becomes the choice of our place. When we enquired about a suitable place, then we came to contact with UNIQUE CLASSES in JINDAL NAGAR. We liked the place and overtaken the UNIQUE CLASSES and merged our venture CRACKGATE EDUCATION. The new entity will be named as UNIQUE CLASSES and it will be run by us.

UNIQUE CLASSES : JINDAL NAGAR

Address: SHYAM HOSTEL; JINDAL NAGAR
NEAR PUNJAB & NATIONAL BANK

Call at 7500113349; 9555921800

THE COURSES OFFERED BY US
COACHING FOR GATE 2015 in MECHANICAL ENGINEERING.

Complete syllabus will be covered

@Rs. 2000 per month

Introducing BACK PAPERS coaching for sure pass in (@Rs.1300 per subject)

Engineering Mechanics

Applied Thermodynamics

Mathematics

Sensors and instrumentation

Physics

Regular Classes for 1st, 3rd and 5th Mechanical Engineering Subjects,

Engineering Mechanics (1st Sem)

Engineering Mathematics (1st Sem)

Thermodynamics(3rd Sem)

Fluid Mechanics(3rd Sem)

Strength Of Materials (3rd Sem)

I C Engines & Comptessors (5th Sem)

Heat and Mass Transfer (5th Sem)

Subhankar Karmakar

SAMPLE SHEET: GATE 2015; STRENGTH OF MATERIALS (MECHANICAL ENGINEERING)

CRACKGATE EDUCATION

House No: 237; Sector – 5; Chiranjeev Vihar, Ghaziabad

                     Contact No : #9555921800

PRACTICE WORKSHEET GATE-2015

MECHANICAL ENGINEERING

TOPIC: STRENGTH OF MATERIALS

Difficulty Level: 1

SET ONE: Each question has several entries, choose the most appropriate one

01)  The intensity of stress which causes unit strain is called

            a) unit stress                                                     b) bulk modulus

            c) modulus of elasticity                                               d) principal stress

02)  Which of the following materials has poisson’s ratio more than unity

            a) steel                                                                         b) copper

            c) cast iron                                                       d) none of these

03) The change in the unit volume of a material under tension with increase in its Poisson’s ratio will

            a) increase                                                       b) decrease

            c) increase initially and then decrease              d) remain same

04) In a tensile test, near the elastic zone, the tensile strain

            a) increases more quickly                                b) decreases more quickly

            c) increases in proportion to the stress                         d) increases more slowly

05) The stress necessary to initiate yielding is

            a) considerably greater than that necessary to continue it

            b) considerably lesser than that necessary to continue it

            c) remain same to continue it

            d) can’t be predicted

06) Flow stress corresponds to

            a) fluids in motion                                           b) breaking point

            c) plastic deformation of solids                                   d) rupture stress

07) The maximum strain energy that can be stored in a body is known as

            a) impact energy                                              b) resilience

            c) proof resilience                                            d) modulus of resilience

08) Thermal stress is always

            a) tensile                                                          b) compressive

            c) tensile or compressive                                 d) none of these

09) The loss of strength in compression due to overloading is known as

            a) hysteresis                                                     b) relaxation

            c) creep                                                            d) Bouschinger effect

10) If a material expands freely due to heating, it will develop

            a) thermal stress                                               b) lateral stress

            c) creep stress                                                  d) no stress

SAMPLE SHEET: GATE 2015; FLUID MECHANICS (MECHANICAL ENGINEERING)

CRACKGATE EDUCATION

House No: 237; Sector – 5; Chiranjeev Vihar, Ghaziabad

                     Contact No : 09678534833; 09555921800

PRACTICE WORKSHEET GATE-2015

MECHANICAL ENGINEERING

TOPIC: FLUID MECHANICS

Difficulty Level: 1

SET ONE: Each question has several entries, choose the most appropriate one

01) If no resistance is encountered due to displacement then such a substance is called

            a) fluid               b) real gas                 c) ideal fluid          d) visco-elastic fluid

02) The volumetric change of a fluid due to a resistance is called as

            a) volumetric strain,                             b) volumetric index

            c) compressibility                                d) cohesion

03) Mercury does not wet glass due to a property of liquids known as

            a) adhesion                                          b) cohesion

            c) viscosity                                          d) surface tension

04) The surface tension of Mercury at normal temperature compared to that of water is

            a) more                                                          b) less

            c) depends upon the glass tube                        d) equal

05) Kinematic viscosity is dependent upon

            a) pressure       b) distance       c) density         d) flow

06) Alcohol is used in manometers because

            a) it is clearly visible                            b) it provides suitable meniscus

            c) it can provide longer column due to its low density

            d) it has low surface tension

07) The buoyancy depends upon

            a) mass of liquid displaced                  b) viscosity of the liquid

            c) pressure of the displaced liquid       d) none of the above

08) The centre of gravity of the volume of the liquid displaced by an immersed body is called

            a) meta-centre                                      b) centre of gravity

            c) centre of pressure                            d) centre of buoyancy

09) Surface energy per unit area of a surface is numerically equal to

            a) atmospheric pressure                                   b) surface tension

            c) force of cohesion                                         d)  viscosity

10) Flow occurring in a pipeline when a valve is being opened is

            a) steady flow                                                 b) unsteady flow

            c) laminar flow                                                d) vortex flow

For answers contact at 09555921800

SAMPLE SHEET: GATE 2015; THERMODYNAMICS (MECHANICAL ENGINEERING)

CRACKGATE EDUCATION

House No: 237; Sector – 5; Chiranjeev Vihar, Ghaziabad

                     Contact No : #9555921800

PRACTICE WORKSHEET GATE-2015

MECHANICAL ENGINEERING

TOPIC: BASIC THERMODYNAMICS

Difficulty Level: 1

SET ONE: Each question has several entries, choose the most appropriate one

01) Gas laws are applicable to

            a) Gases as well as vapours     b) Gases alone and not applicable to vapours

            c) Gases and Steam                  d) Gases and Superheated vapours

02) An ideal gas compared to a real gas at very high pressures occupies

            a) more volume           b) less volume            

c) same volume           d) can’t be predicted

03) Temperature of a gas is produced due to

            a) its heating value                   b) kinetic energy of the molecules

            c) molecular vibration              d) inter-molecular attractions

04)  According to kinetic theory of gases, the absolute zero temperature is attained when

            a) volume of the gas is zero                             b) pressure of the gas is zero

            c) kinetic energy of the molecule is zero                     d)  specific heat is zero 

05)  The quantity δQ – δW; where δQ is elemental heat transfer and δW is the elemental work    

transfer is

            a) path function                       b) point function

            c) cyclic function                     d) in-exact differential

06)  The workdone in an adiabatic process between a given pair of end states depends on

            a) the values of the endstates only,      b) the end states and specific heat ratio  γ

            c) the end states and polytropic index n,          d) none of the above.

07)  If the value of polytropic index n is high, then the compressor work between given pressure limits will be

            a) less                                      b) more

            c) no effect                              d) zero

08)  A perfect gas at 27^oC is heated at constant pressure till its volume becomes double. The final temperature will be

            a) 54^oC                                    b) 327^oC

            c) 108^oC                                  d) 600^oC

09)  Mixing of ice and water at 0^oC at atmospheric pressure is an example of

            a) reversible process                b) irreversible process

            c) quasi-static process              d) isentropic process

10)  Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant

            a) pressure                               b) temperature

            c) volume                                d) entropy

GATE 2015: MECHANICAL ENGINEERING COACHING IN CHIRANJEEV VIHAR AND GOVINDPURAM GHAZIABAD

GATE 2015

MECHANICAL ENGINEERING COACHING IN

CHIRANJEEV VIHAR AND GOVINDPURAM

THE SALIENT POINTS OF THE COURSE:

• THE COURSE HAS BEEN DESIGNED TO HELP THOSE STUDENTS WHO HAVE DIFFICULTIES IN THE BASIC CONCEPTS.
• AT FIRST THE BASIC CONCEPTS WOULD BE TAUGHT AND THEN ADVANCED CONCEPTS WILL BE INTRODUCED.
• WHILE TEACHING A CONCEPT, SIMULTANEOUSLY MULTIPLE CHOICES QUESTIONS WILL BE SHOWN FROM THAT CONCEPT.
• MORE THAN 2500 MULTIPLE CHOICES QUESTIONS WILL BE DISCUSSED WITH SOLUTIONS.
• PROBLEM SOLVING TECHNIQUES WOULD BE TAUGHT WITH THE HELP OF MASTER CHARTS.
• TWO HOURS PER DAY SIX DAYS PER WEEK CLASSES.
• CLASSES ON IMPROVING LEARNING ABILITIES, INCREASING CONCENTRATION AND THE SCIENTIFIC STUDYING TECHNIQUES WILL BE TAKEN.
• CONCEPTS WOULD BE TAUGHT USING ANIMATIONS, GRAPHS, PICTOGRAMS, MNEMONICS AND OTHER LEARNING ENHANCEMENT TOOLS.
• ONLY 20 STUDENTS PER BATCH TO FOCUS MORE ON THE INDIVIDUAL NEEDS OF THE STUDENTS.
• ASSISTANCES FOR INDIVIDUAL PSU (LIKE ONGC, IOC etc.)
• TRIAL CLASSES ARE THERE TO BE AWARE OF THE PERFORMANCES OF THE CLASSES.
• HIGH TECH STUDY MATERIALS AT AFFORDABLE PRICE.
• COURSE DURATION IS SIX MONTHS.
• INTRODUCTORY PRICES ARE AS LOW AS @₨ 2500 PER MONTH
• CLASSES WILL BE STARTED FROM 25^th JULY; 2014
• CALL AT # +91-9458042791; +91-9555921800; +91-9678534833

CRACKGATE EDUCATION

House No: 237; Sector – 5; Chiranjeev Vihar, Ghaziabad

                     Contact No : +91-9458042791; +91-9555921800; +91-9678534833

ENGINEERING DRAWING

अर्धबार्षिक परीक्षा प्रश्न पत्र  2013 

इंजीनियरिंग ड्राइंग 

प्रथम वर्ष  यांत्रिक इंजीनियरिंग 

___________________________________________________________________

[ समय : 2 घंटा ]                                                                                   पूर्णांक : 30 

               नोट : किन्ही तीन प्रश्नो के उत्तर दीजिये। प्रश्न संख्या 4 अनिवार्य है। 

                         प्रत्येक प्रश्न के अंक प्रश्न के सामने अंकित है। 

               1 ) 10 mm ऊंचाई के एकल प्रयास उर्ध्वाधर कैपिटल अक्षरों मैं निम्नलिखित वाक्य को        

                    स्वच्छता पूर्वक लिखिए।                                                                        (7. 5 )

                         "CIVIL ENGINEERING IS THE BACKBONE OF CIVILIZATION."

               2 ) एक रेखा AB , HP से 60^o का कोण बनाती है, तथा VP से 25 mm पीछे समानांतर है।  
                    यदि रेखा के सिरा 'A' H.P. से 25 mm निचे है , तथा रेखा की लम्बाई 50 mm है , तब रेखा 
                   के Front  View एबं Top View बनाइये।                                                    (7. 5 )

               3) (1 /50) निरूपक भिन्न (R. F.) वाली एक निकर्ण मापनी बनाइये जिस पर मीटर , 
                   डेसीमीटर तथा सेन्टीमीटर का मापन किया जा सके तथा 9 मीटर लम्बाई तक पढ़ने के 
                   लिए पर्याप्त हो। मापनी पर 6.47 मीटर की दूरी चिह्नित कीजिये।            (7. 5 )


               4) चित्रों मई एक समपरिमन दृश्य (Isometric View) दर्शाया गया है , दी गई दिशाओं से 
                   देखकर इनका अनुविक्षेप (Plan/ Top View) एबं  उत्सेध (Front View) तथा पार्श्व दृश्य 
                   ( Side View ) को III^rd Angle मैं बनाइये।                                                ( 15 )

ME-301: THERMODYNAMICS FOR THIRD SEMESTER; UPTU

SECTION A: Each question carry 2 marks

01) What is point function and path function?

02) Define Enthalpy.

03) What is SFEE?

04) What is internal energy of a system

05) What is vapour dome and dryness factor?

06) What is saturated liquid line and saturated vapour line?

07) What is triple point of water?

08) Define specific heats of ideal gases.

09) Write the reduced form of Vander Waals equation for real gases.

10) Define a thermodynamic system.

11) State with reasoning whether the following systems are closed, open or isolated
i) Refrigerator; ii) Pressure Cooker

12) Distinguish between isolated system and adiabatic system.

13) Explain the concept of flow work

14) What is control volume and control surface?

15) When does a real gas behave like an ideal gas?

16) What are extensive and intensive properties?

17) What is enthalpy of evaporation of steam?

18) Define degree of under-cooling and degree of superheat.

19) What is COP of a heat pump?

20) Define throttling process.

21) Define entropy.

22) Two moles of an ideal gas occupy a volume of 4.24 m³ at 400 K temperature. Find the pressure exerted by the gas.

23) Distinguish between refrigerator and heat pump.

24) What is Free Expansion?

25) Explain Zeroth law of thermodynamics.

26) Explain the concept of compressibility factor?

27) What is PMM-1.

28) What is a superheated steam?

29) Distinguish between universal gas constant and characteristic gas constant.

30) What is Exergy?

31) Distinguish between quasi-static process and reversible process.

32) What is a diathermal system boundary?

33) What is a steady flow open system?

34) What is the difference between latent heat and sensible heat?

35) What is a thermodynamic cycle?

36) Distinguish between restraint and unrestraint process.

37) What is a thermodynamic definition of work?

38) What is work of evaporation?

39) What is a pure substance?

40) What is the concept of continuum?

41) Define thermodynamic state, process and path.

42) Distinguish between thermal equilibrium and thermodynamic equilibrium.

43) What are the conditions for reversible process?

44) Distinguish between heat and work.

45) What are the differences between gas and vapour?

SECTION B: Attempt any three of the following questions. Each question contains two parts of 5 marks each. Total marks In this section is 3x10 = 30

01) a) State Zeroth law of thermodynamics and explain how it leads to the concept of temperature.

b) Explain different types of temperature scale and the relations among them.

02) a) Explain the corollaries of first law of thermodynamics.

b) 2 kg of air is confined in a rigid container of 0.42 m³ at 4 bar pressure. When heat energy of 164 kJ is added, its temperature becomes 127°C.
Find :

i) Work done by the system.
ii) Change in internal energy.
iii) Specific heat at constant volume.

03) a) Derive an expression for heat transfer and work done in a polytropic process.

b) 1.5 kg of oxygen contained in a cylinder at 4 bar pressure and 300 K expands three times its original volume in a constant pressure process. Determine
i) Initial volume, ii) Final temperature, iii) Work done by the gas, iv) Heat added and v) Change in internal energy.
; Assume C_p = 1.005 kJ/kg-K and R = 260 J/kg-K

04) a) Make steady flow energy analysis on a turbine.

b) Find the velocity and diameter at exit of a nozzle if 5 kg/s air at 9 bar and 200°C expands through the nozzle up to pressure at 1.1 bar. Approach velocity is 50 m/s.

05) a) Differentiate between absolute pressure and gauge pressure. What is a manometer?

b) An ideal gas of molecular weight 42.4 has a pressure of 10 bar and occupies a volume of 0.3 m³ at 27°C. Determine the characteristic gas constant for the ideal gas, its mass and number of moles.

06) a) Write the first law of thermodynamics for a flow process. Derive an expression for flow work.

b) Find the total work done and efficiency for a reversible Carnot cycle.

07) a) What is continuity equation in flow process?

b) 3 kg air at 2 bar pressure and 27℃ temperature has been compressed isothermally till the pressure reaches 6 bar. Next it has been heated at constant pressure and thereafter reaches the initial state by expanding adiabatically. Find the maximum Temperature reached in the cycle and total work done by the system.

08) a) Explain the Joule's experiment.

b) Prove that internal energy is a point function.

09) a) What is thermodynamic temperature scale?

b) i) A heat engine running between 300 K and 800 K generates 2000 kJ of energy. Find the total heat extracted from the source.
ii) Determine the power required to run a refrigerator that transfers 2000 kJ/min of heat from a cooled space at 0°C to the surroundings atmosphere at 27°C.

10) a) What is PMM - 2? State Kelvin-Planck statement of second law of thermodynics.

b) A heat engine running between two thermal reservoirs of 800 K and 300 K is used to power a refrigerator running between two thermal reservoirs of 325 K and 260 K. If the heat engine draws 5000 kJ heat from reservoirs at 800 K, then find the amount of heat extracted from 260 K reservoir by the refrigerator.

11) a) Explain the Vander Waal's gas equation.

b) 4 kg of steam at 16 bar occupies a volume of 0.28 m³. The steam expands at constant volume to a pressure of 8 bar. Determine the final dryness fraction, final internal energy and change in entropy.

12) a) Explain and derive Clausius Inequality.

b) 3 kg of air is heated reversibly at constant pressure of 2.5 bar from 23°C to 227°C. If the lowest available temperature is 20°C determine the increase in the available energy of air due to heating. Take C_p = 1.005 kJ/kg-K.

13) a) What is thermodynamic definitions of work? Distinguish between ∫pdV work and other types of work.

b) 3 kg of air at 1.5 bar pressure and 350 K is compressed isothermally to a pressure of 6 bar. Then heat of 350 kJ is added at constant volume. What will be the maximum temperature of air during the process? Find the total work done in the processes. Also find the change in internal energy of air.

14) a) Write the limitations of second law of thermodynamics. Prove that C_p - C_v = R

b) 10 kg of air at 300 K is stored in a totally insulated cylinder of volume 0.3 m³/kg. If 1 kg air has been taken out of the system, then what will be the value of new pressure?

15) a) Steam at 1.2 bar and a dryness fraction of 0.5 is heated at constant pressure until it becomes saturated vapour. Calculate the heat transferred per kg of steam.

b) Steam at 8 MPa and 500°C passes through a throttling process such that the pressure is suddenly dropped to 0.3 MPa. Find the expected temperature after throttling.

16) a) What are the causes of irreversibility?

b) Distinguish between a quasi-static process and reversible process.

17) a) 3 kg of air at 400 K and 4 bar pressure adiabatically mixed with 4 kg of air at 500 K and 3 bar pressure. Find the change in entropy of the universe.

b) Explain the principle of increase of entropy.

SECTION C : marks 50, 5 questions of 10 mark each. Each question contains 3 parts. Attempt any two parts out of three from each question.

01) a) Steam at 20 bar pressure and 300°C expands isentropically in a turbine to a pressure of 2 bar. Find the final condition of the steam. Also Calculate the work delivered by the turbine.

b) What is isentropic efficiency of a turbine? Calculate internal energy of steam at 6 bar pressure and 300°C.

c) Explain the steam formation process at constant pressure.

02) a) What is adiabatic mixing of two ideal gases? Derive the expressions for final temperature and pressure.

b) 5 kg of steam at 8 bar pressure and 200°C mixed with 3 kg of steam at 5 bar and dryness fraction x = 0.8 adiabatically. Find the final condition of the steam.

c) 5 kg of air at 4 bar pressure is heated at constant pressure from 300 K to 500 K. Find the change in entropy of the system.

03) a) Prove that in an adiabatic process pV^γ = Constant.

b) Polytropic compression of air from state 1 to state 2 where p₁ = 100 kPa and T₁ = 300 K, p₂ = 300 kPa and n = 1.2 where as mass of air is 3 kg. If R = 0.287 kJ/kg-K. Then find

i) heat exchange during the process
ii) change in internal energy
iii) total work done by the air
iv) change in entropy


c) A non flow reversible process occurs for which pressure and volume are correlated by the relation p = (V² + 6V), where V is the volume in m³ and pressure p is in bar. Determine work done if volume changes from 3 to 6 m³.

04) a) A gas expands according to the equation pv = 100, where " p " is the pressure in kPa and " v " is the specific volume. Initial and final pressures are 1000 kPa and 500 kPa respectively. The gas is then heated at constant volume back to it'd original pressure of 1000 kPa. Determine the net work done. Also sketch the processes in p-v coordinates.

b) What is the definition of thermodynamic work?

c) What is the efficiency of a thermodynamic cycle?

05) a) What is paddle work? Distinguish between ∫pdV work and ∫-vdp work.

b) If pV = mRT, determine whether the expression (V/T).dp + (p/T).dV is a property of a system.

c) 2 kg of air at 1 bar pressure and 300 K is compressed adiabatically to a pressure of 6 bar. Then heat of 200 kJ is added at constant pressure. What will be the maximum temperature of air during the process? Find the total work done in the processes. Also find the change in internal energy of air.

06) a) Find the expression for heat transfer in terms of work done in a polytropic process.

b) What is the specific heat C_n for a polytropic process?

c) 2 kg of air at pressure 2 bar and 300 K is compressed reversibly to 4 bar and 650 K temperature in a polytropic process. Determine the polytropic index (n) of the process.

07) a) Find an expression for mechanical work in steady flow process.

b) What is the meaning of - vdp work?

c) Air flows through a gas turbine system at a rate of 5 kg/s. It enters with a velocity of 150 m/s and an enthalpy of 1000 kJ/kg. At exit the velocity is 120 m/s and enthalpy is 600 kJ/kg. If the air passing through the turbine looses 30 kJ/kg of heat to the surroundings, determine the power developed by the system.

08) a) Write the assumptions considered in Kinetic theory of gases? Prove that C_p - C_v = R

b) Explain the law of corresponding states.

c) 10 kg of air at 300 K is stored in a cylinder of volume 0.3 m³/kg. Find the pressure exerted by air using Vander Waals gas equation. Critical properties of air are: P_c = 37.7 bar, T_c = 132.5 K, v_c = 0.093 m³/kg_mole, R = 287 J/kg-K

09) a) What are the limitations of Vander Waals gas equation? Explain reduced properties of a real gas?

b) What is a undercooled liquid and degree of undercooling? Also define enthalpy of water.

c) What are the properties of steam at critical state? Explain sublimation process and triple point line.

10) a) What are the differences between dry saturated steam and superheated steam at a same pressure? Also, explain vapourdome, saturated liquid line, saturated vapour line and critical point.

b) What are the differences between work of evaporation and enthalpy of evaporation?

c) An inventor claims to have developed a refrigeration unit which maintains −10℃ in the refrigerator which is kept at a room where the surrounding temperature is 25℃ and which has COP of 8.5. Find the claim of the inventor is possible or not.

11) a) Prove that the absolute zero temperature is impossible to achieve according to second law of thermodynamics.

b) Two reversible heat engines A and B are arranged in series. A rejects heat directly to B. Engine A receives 200 kJ at a temperature of 421℃ from the hot source while engine B is in communication with a cold sink at a temperature of 5℃. If work output of A is twice that of B, find :
(i) Intermediate temperature between A and B.
(ii) Efficiency of each engine.
(iii) Heat rejected to the sink.


c) Prove that the reversible heat engines are the most efficient.

12) a) Steam at 1 bar and a dryness fraction of 0.523 is heated in a rigid vessel until it becomes saturated vapour. Calculate the heat transferred per kg of steam.

b) Steam at 9 MPa and 600°C passes through a throttling process such that the pressure is suddenly dropped to 0.4 MPa. Find the expected temperature after throttling.

c) What will be the quality of the steam at the end of adiabatic expansion of steam at 12 bar pressure and 400°C to 1.2 bar in a turbine. Also, find the ideal work out put by the turbine.

13) a) Explain the change of entropy in a perfectly isolated system during a process in the system.

b) Explain the conditions those must be satisfied by a reversible process.

c) Two kg of water at 90℃ is mixed with three kg of water at 10℃ in a perfectly isolated system. Calculate the change in entropy of the system.

14) a) Explain the second law of thermodynamics and prove that no engine can have a 100% efficiency.

b) Explain the theoretical Carnot cycle and derive its efficiency with diagrams.

c) A reversible engine working in a cycle takes 4800 kJ of heat per minute from a source at 800 K and develops 35 kW power. The engine rejects heat to two reservoirs at 300 K and 360 K. Determine the heat rejected to each sink.

15) a) What are the causes of external irreversibility?

b) Write the first and second Tds equations and derive the expression for the change of entropy during a polytropic process.

c) Prove that reversible engines are most efficient.

16) a) Explain the second law of thermodynamics.

b) Derive the Clausius inequality.

c) Steam at 160 bar and 550℃ is supplied to a steam turbine. The expansion of steam is adiabatic with increase in entropy of 0.1 kJ/kg-K. If the exhaust pressure is 0.2 bar, calculate specific work of expansion.

17) a) 5 kg of water at 400 K is isobarically and adiabatically mixed with 3 kg of water at 500 K. Find the change in entropy of the universe.

b) Explain i) Second law efficiency, ii) Effectiveness of a system and iii) Availability of a closed system.

c) Explain the principle of increase of entropy.

18) a) Explain Helmholtz and Gibbs function.

b) Explain the concept of PMM-I and PMM-II.

c) Find an expression of exit velocity C₂ in terms of pressure ratio when air passes through a nozzle from a pressure of p₁ and temperature T₁ to a pressure p₂.

19) a) Distinguish between enthalpy and internal energy.

b) What is absolute or thermodynamic temperature? Explain briefly.

c) Two Carnot engines work in series between the source at temperature 500 K and sink at temperature 300 K. If both develop equal power, determine the intermediate temperature.

20) a) Show that two adiabatic curves on p-V diagram never intersects each other.

b) Define and classify thermodynamic systems.

c) In an isentropic flow through nozzle, air flows at the rate of 600 kg/hr. At inlet to the nozzle pressure is 2 MPa and temperature is 27℃. The exit pressure is 0.5 MPa. Initial air velocity is 300 m/s, determine
i) exit velocity of air
ii) inlet and exit area of the nozzle

THE END