Question Bank - Thermodynamics

QUESTION BANK

 

Question No.	Questions	Bloom’s Level
PART-A (Two Marks Questions)
UNIT 1 - BASIC CONCEPTS OF THERMODYNAMICS
1	Define the term “Thermodynamics”.	BT1
2	Define the term “An open system”.	BT1
3	Define the term “A closed system”.	BT1
4	Define the term “An isolated system”.	BT1
5	What is meant by intensive properties and give some examples.	BT1
6	What is meant by extensive properties and give some examples.	BT1
7	Define the term “Continuum”.	BT1
8	What is meant by Macroscopic viewpoints?	BT1
9	What is meant by Microscopic viewpoints?	BT1
10	What is meant by reversible cycle?	BT1
11	What is meant by irreversible cycle?	BT1
12	Explain briefly “Quasi-static process”.	BT1
13	Define the term “Mechanical equilibrium”.	BT1
14	Define the term “Thermal equilibrium”.	BT1
15	Define the term “Chemical equilibrium”.	BT1
UNIT 2 - FIRST LAW OF THERMODYNAMICS
1	Define the term “State of a system”.	BT1
2	What is meant by Point function?	BT1
3	What is meant by Path function?	BT1
4	State “Law of conservation of energy”.	BT1
5	Define the term “Potential energy”.	BT1
6	Define the term “Kinetic energy”.	BT1
7	Define the term “Internal energy”.	BT1
8	Define the term “Heat” and how it can transferred in different distinct ways?	BT1
9	Define the term “Specific heat”.	BT1
10	Define the term “Thermal capacity”.	BT1
11	What is meant by water equivalent?	BT1
12	State “Zeroth law of thermodynamics”.	BT1
13	State “First law of thermodynamics”.	BT1
14	What are the limitations of first law of thermodynamics?	BT1
15	Write the relationship between Cp and Cv?	BT2
UNIT 3 - SECOND LAW OF THERMODYNAMICS AND THERMODYNAMIC  RELATIONS
1	Write the name of two statements in second law of thermodynamics.	BT1
2	State “Kelvin - Planck statement” in second law of thermodynamics.	BT1
3	State “Clausius statement” in second law of thermodynamics.	BT1
4	What are the various thermodynamics process involved in Carnot cycle?	BT1
5	Why Carnot cycle efficiency is higher than all other cycles?	BT1
6	Why Carnot cycle cannot be performed in practice?	BT1
7	A Carnot engine working between 650K and 310K, produces 150 kJ of work. Find thermal efficiency and heat added during the process.	BT2
8	An engine operating on a Carnot cycle works with in temperature limits of 600K and 300K. If the engine receives 2000 kJ of heat. Evaluate the workdone and thermal efficiency of the engine.	BT2
9	A Carnot cycle operates between source and sink temperature of 250°C and -15°C respectively. If the system receives 90 kJ from the source. Find: (i) efficiency of the system and (ii) the net work transfer.	BT2
10	A cyclic heat engine operates a source temperature of 100°C and a Sink temperature of 40°C. Find the least rate of heat rejection per kw net output of the engine.	BT2
11	Define the term “Entropy”.	BT1
12	State “Clausius inequality”.	BT1
13	State “Third law of thermodynamics”.	BT1
14	Define the term “Helmholtz function”.	BT1
15	Define the term “Gibbs function”.	BT1
UNIT 4 - PROPERTY OF PURE SUBSTANCES AND POWER CYCLES
1	What is meant by pure substance?	BT1
2	Define the term “Latent heat of ice”.	BT1
3	Define the term “Sensible heat of water”.	BT1
4	What is meant by wet and dry steam and which term is used denoted for it?	BT1
5	Define the term “Latent heat of vaporization”.	BT1
6	What is meant by superheated steam and indicate its use.	BT1
7	Define the terms “Degree of super heat”.	BT1
8	What is meant by triple point and indicate in diagram.	BT1
9	What is meant by PVT surface?	BT1
10	What is meant by critical point for pure substance?	BT1
11	Define the term “Stroke volume”.	BT1
12	What is the necessity of providing clearance volume in an IC engines?	BT1
13	What is meant by total volume?	BT1
14	Define the term “Compression ratio”.	BT1
15	Define the term “Cutoff ratio”.	BT1
UNIT 5 - REFRIGERATION AND AIR CONDITIONING
1	What is meant by refrigeration and air conditioning?	BT1
2	Define the term ‘Unit of refrigeration’.	BT1
3	What is meant by relative COP?	BT1
4	Explain the term “Tonne of refrigeration”.	BT1
5	A machine working on reversed Carnot cycle operates between 300C and -150C. Determine COP, when it is operated as refrigerator.	BT2
6	A refrigerating machine working on reversed Carnot cycle consumes 6kW for producing refrigerating effect of 1000kJ/min. Determine the COP of machine.	BT2
7	Describe the essential components of the refrigeration plant.	BT1
8	Draw the T-S and p-h diagram for vapour compression refrigeration systems.	BT1
9	How the refrigerants are classified?	BT1
10	List out some name of secondary refrigerants used in refrigeration systems.	BT1
11	State the desirable properties of ideal refrigerants.	BT1
12	Classify air conditioning systems.	BT1
13	Define room sensible heat factor (RSHF).	BT1
14	What are the factors affecting optimum effective temperature?	BT1
15	What are the factors affecting human comfort?	BT1

 

QUESTION BANK

 

 

Question No.	Questions	Bloom’s Level
PART-B (Ten Marks Questions)
UNIT 1 - BASIC CONCEPTS OF THERMODYNAMICS
1	A fluid at of pressure of 3 bar and with volume of 0.18 m³/kg contained in cylinder behind a piston expands reversibly to a pressure of 0.6 bar. According to law a P = C/V2, where C is a constant. Calculate the workdone by the fluid on the piston.	BT4
2	A temperature scale of certain thermometers is given by the relation: t = a ln(p) + b, where ‘a’ and ‘b’ are constant and ‘p’ is the thermometric property of the fluid in the thermometer. If at the ice point and steam point of the thermometric properties are found to be 1.5 and 7.5 respectively. What will be the temperature corresponding to the thermometric property of 3.5 on Celsius scale.	BT4
3	A temperature scale of certain thermometers is given by the relation: t = a ln(k) + b, where ‘a’ and ‘b’ are constant and ‘k’ is the thermometric property of the fluid in the thermometer. If at the ice point and steam point of the thermometric properties are found to be 1.83 and 6.78 respectively. What will be the temperature corresponding to the thermometric property of 2.42 on Celsius scale.	BT4
4	Prove that Cp-Cv=R and determine the relationship between Cp, Cv, R and also find the adiabatic index (γ).	BT2
5	The properties of a closed system change following the relation between pressure and volume as PV=3, where p in bar, V in m3. Calculate the workdone when the pressure increases from 1.5bar to 7.5bar.	BT4
6	A barometer reads 76cm of Hg. What would be the absolute pressure if; (i)      A pressure gauge connected to turbine inlet reads 28bar and (ii)    A vacuum gauge connected in the outlet line of the same turbine reads 70cm of Hg.	BT4
7	Determine the work done by the air which enters into an evacuated vessel from atmosphere when the valve is opened. The atmosphere pressure is 1.013 bar and 1.5m³ air at atmosphere condition enters into the vessel.	BT4
8	A mass of 1.5kg air is compressed in a quasi-static process from 0.1MPa to 0.7MPa for which PV = constant. The initial density of air is 1.16 kg/m³. Find the workdone by the piston to compress the air.	BT4
9	During the compression stroke of reciprocating compressor, the workdone to the air in the cylinder is 95 kJ/kg and 43 kJ/kg of heat is rejected to the surroundings. Determine the change in internal energy.	BT4
10	State law’s of perfect gases and how the laws are governed by variables?	BT2
UNIT 2 - FIRST LAW OF THERMODYNAMICS
1	State the first law of thermodynamics and prove that first law is the law of conservation of energy for a non-flow process and it leads to the energy equation δQ = dU+δW.	BT2
2	A stationary mass of gas is compressed without friction from an initial state of 0.3 m³ and 0.105 MPa to a final state of 0.15m³ and 0.105 MPa. The pressure remains constant during the process. There is a transfer of 37.6 kJ of heat from the gas during the process. How much does the internal energy of the gas change?	BT4
3	A mass of 0.25 kg of air in a closed system from 2 bar, 600C to1 bar, 40°C, while receiving 1.005kJ of heat from a reservoir at 1000C. The surrounding atmosphere is at 0.95 bar and 270C. Determine the maximum work.	BT4
4	List out the heating and expansion of gases in non-flow processes and derive the expression for P-V-T relation, workdone, change in internal energy, heat supplied and change in enthalpy by using constant volume process.	BT2
5	List out the heating and expansion of gases in non-flow processes and derive the expression for P-V-T relation, workdone, change in internal energy, heat supplied and change in enthalpy by using constant pressure process.	BT2
6	A certain gas occupies a space of 0.3m³ at a pressure of 2 bar and temperature of 77oC. It is heated at a constant volume until the pressure is 7 bar. Determine: (i) temperatures at the end of the process, (ii) mass of the gas, (iii) change in internal energy and (iv) change in enthalpy during the process. Assume Cp =1.005 kJ/kg.K, Cv=0.712kJ/kg.K.	BT4
7	The values of specific heats at constant pressure and at constant volume for an ideal gas are 0.984 kJ/kg.K and 0.728 kJ/kg.K. Find the values of characteristic gas constant (R) and ratio of specific heats for the gas. If 1 kg of this gas is heated at constant pressure from 25°C to 200°C. Estimate the heat added, ideal workdone and change in internal energy. Also calculate the pressure and final volume. If the initial volume was 2m³.	BT4
8	Derive the expression application of first law of thermodynamics to a steady flow process.	BT2
9	Derive the steady flow energy equations for the flowing applications in engineering systems: (i) Boiler, (ii) Nozzle and (iii) turbine.	BT2
10	Derive the steady flow energy equations for the flowing applications in engineering systems: (i) Evaporator, (ii) Condenser and (iii) Compressor.	BT2
UNIT 3 - SECOND LAW OF THERMODYNAMICS AND THERMODYNAMIC  RELATIONS
1	State the second law of thermodynamics and find COP of heat pump and refrigerator.	BT2
2	Derive the expression for Carnot cycle and what reasons it cannot be performed in practice?	BT2
3	Derive the expression of change in entropy of a perfect gas in the process of constant volume.	BT2
4	Derive the expression of change in entropy of a perfect gas in the process of constant pressure.
5	Derive the expression of change in entropy of a perfect gas in polytropic process.	BT2
6	A vessel of 2.5m3 capacity contains 1kg-mole of nitrogen at 1000C. If the gas cooled to 300C. Calculate the change in specific entropy. The ratio of specific heats is 1.4 and 1kg-mole nitrogen is 28kg.	BT4
7	Cold air from atmosphere is circulated through an air heating system, where the temperature of air is increased from 7.20C to 21.20C without any pressure loss. If the hourly consumption of warm air at 21.2°C is 850m³. Calculate: (i) how much heat per hour must be imparted to the air, (ii) what will be the change in entropy of air circulated per hour? Assume proper values of the specific heat of air.	BT4
8	A fluid undergoes a reversible adiabatic compression from 4bar, 0.3m3 to 0.08m3. According to the law, PV1.25=C. Determine: (i) change in enthalpy, (ii) change in internal energy, (iii) change in entropy and (iv) heat and work transfer during the process.	BT4
9	Drive the expression of “Maxwell equations”.	BT2
10	Explain about the “Helmholtz function” and “Gibbs function” and determine the workdone of these functions.	BT2
UNIT 4 - PROPERTY OF PURE SUBSTANCES AND POWER CYCLES
1	Explain about the formation of steam with the help of T-dQ diagram.	BT2
2	Explain the following indicator diagram for a pure substance: (i)     Pressure - Temperature (P-T),  (ii)   Temperature - Volume (T-V), and (iii)  Temperature – Specific Enthalpy (T-h),	BT2
3	Explain the following indicator diagram for a pure substance: (i)     Pressure - Volume - Temperature (P-V-T) surface and (ii)    Specific Enthalpy - Specific Entropy(h-S)	BT2
4	Find the dryness fraction, specific volume and specific internal energy of steam at 7bar and enthalpy 2550 kJ/kg.	BT4
5	Two boilers one with superheater and other without superheater are delivering equal quantities of steam into a common main. The pressure in the boilers and main is 20 bar. The temperature of steam from a boiler with a superheater is 350°C and temperature of the steam in the main is 250°C. Determine the quality of steam supplied by the other boiler. Take; Cps =2.25 kJ/kg.K	BT4
6	Explain the measurement of dryness fraction of steam by using bucket calorimeter.	BT2
7	Explain the construction and working of an Otto cycle.	BT2
8	Explain the construction and working of a Diesel cycle.	BT2
9	Distinguish between air standard cycle and actual cycle.	BT2
10	Distinguish between Otto cycle and Diesel cycle.	BT2
UNIT 5 - REFRIGERATION AND AIR CONDITIONING
1	Explain the main components in vapour compression refrigeration system with neat sketch.	BT2
2	Explain with a flow diagram, the working of aqua-ammonia vapour absorption refrigeration system.	BT2
3	Explain about physical, safe working and thermodynamic properties of a ideal refrigerant?	BT2
4	List out the various psychrometric properties of air and explain each.	BT2
5	Draw the psychrometric chart and mention the Psychrometry properties in it.	BT2
6	200 m3 of air at 15°C dry bulb temperature and 75% relative humidity is heated until its temperature is 250C. Find: (i) relative humidity of heated air, (ii) wet bulb temperature of heated air and (iii) Heat added to air/min.	BT4
7	Atmosphere air at a dry bulb temperature of 16°C and 25% relative humidity passes through a furnace and then through a humidifier, in such a way that the final dry bulb temperature is 300C and  relative humidity 50%. Find the heat and moisture added to the air. Also determine the sensible heat factor of the process.	BT4
8	Atmosphere air at 30°c dry bulb temperature and 45% relative humidity is to be conditioned to 17°C dry bulb temperature and 15°C wet bulb temperature. Find the amount of heat rejected by the air. Also find the sensible heat factor of the process.	BT4
9	One kg of air at 400C dry bulb temperature and 50% relative humidity is mixed with 2kg of air at 200C dry bulb temperature and 200C dew point temperature. Calculate the temperature and specific humidity of the mixture.	BT4
10	Define the term “Effective temperature” and mention the factors affecting optimum effective temperature.	BT2

Note:                                                         Bloom’s Taxonomy

Bloom’s Level	Descriptions	Bloom’s Level	Descriptions
BT 1	Remember	BT 2	Understand
BT 3	Apply	BT 4	Analyze
BT 5	Evaluate	BT 6	Create

 

Prepared by

Mr. R.Satheesh Associate Professor