The study of thermodynamics provides answer to the followings, except
Whether a process is feasible or not
How much energy is required for a process to take place
Rate or speed with which a process occurs
Extent to which a reaction/ process takes place
For an isolated system executing a process
no heat is transferred
no work is done
no mass flows across the system boundary
no chemical reaction takes place within the system
Which of the above statements are correct?
1, 2 and 3
1, 3 and 4
2, 3 and 4
1, 2, 3 and 4
Choose the open thermodynamic system
Manual ice cream freezer
Centrifugal pump
Pressure cooker
Automobile storage battery
Which one of the following represents a closed system?
Bomb calorimeter
Steam generator
Universe
Exhaust stroke of an I.C. engine
Identify the heterogeneous system
Atmospheric air
Mixture of hydrogen and oxygen
Cooling fluid in a radiator
Mixture of ice, water and steam
Which aspect is not true regarding thermodynamic property of a system?
A characteristic that describes the condition of the system
A variable whose value depends upon the particular path in going from one state to another
An intensive property is independent of the extent or mass of the system
An extensive property can be made intensive, if it is divided by mass and is called specific property
The value of an extensive property is essentially dependent on
Mass or extent of the system
Interaction of system with its surroundings
Path followed by the system in going from one state to another
Nature of boundaries, rigid or flexible
Which one of the properties given below is an intensive property of the system?
Composition
Volume
Kinetic energy
Entropy
All of the following are intensive properties of a system, except
Viscosity
Temperature
Density
Potential energy
Which one of the followings is the extensive property of a thermodynamic system?
Volume
Pressure
Temperature
Density
Choose the specific property of a thermodynamic system
Viscosity
Density
Pressure
Temperature
Choose the false statement in the context of macroscopic approach followed in classical thermodynamics:
Considers gross behaviour of matter
Requires no hypothesis on the detailed structure of matter
Predicts the behaviour of individual fluid particles by statistical averaging
Deals with characteristics which can be perceived by senses and measured directly
Which one of the following quantities presents the property of a system?
p dv
v dp
(p dv+v dp)
Which aspect is not true concerning microscopic study of thermodynamics?
A knowledge of the structure of matter is essential
A limited number of variables /orioerties are needed to describe the state of matter
The values of these variables cannot be measured
Statistical averaging is adopted to predict the behaviour of individual fluid particles.
A thermodynamic system refers to
Any defined region in space
A specified mass in fluid flow
A specified region of constant volume
A prescribed and identifiable quantity of matter
A closed thermodynamic system manifests when
Matter is not allowed to cross the boundary, but energy transfer does occur across the boundary
There is transfer of both mass and energy across the system boundaries
There is only transfer of mass but no heat and work energy are transferred
There is absolutely no interaction of the system with surroundings across its boundaries
A closed thermodynamic system is one in which
There is no energy or mass transfer across the boundary
There is no mass transfer, but energy transfer exists
There is no energy transfer, but mass transfer exists
Both energy and mass transfer take place across the boundary, but the mass transfer is controlled by valves
In an open thermodynamic system
Mass content of the system under consideration remains same
Transfer of mass and/or energy takes place
There is only mass transfer even though there may not be any exchange of energy with the system environment
The system exchanges energy with the surroundings in the form of heat energy only
A thermodynamic system is referred to be an isolated system when there is transfer of ………….across the system boundaries
Only mass
Only energy
Both mass and energy
Neither mass nor energy
A system and its environment put together constitute
An adiabatic system
An isolated system
A segregated system
A homogeneous system
Which amongst the followings is not a property of the system?
Pressure
Composition
Thermal conductivity
Heat
Identify the false statement in the context of heat and work
They exist only during interaction between the system and the boundary
Are path functions and exact differential
May or may not occur simultaneously
Occur due to some unbalanced potential which tends to promote a change of state
As differentials, heat and work would be described mathematically as
Inexact
Exact
Discontinuity
Point function
Spot the odd one out
Thermal conductivity
Kinetic energy
Work
Pressure
Choose the correct statement
Temperature is an extensive property
Mass remains same in an open system
The system boundaries may expand or collapse
An isolated system allows exchange of energy in the form of heat only
Heat interaction between a system and its surroundings
Represents energy in transit
Does not depend on the choice of the system
Can be identified after the completion of process
Is a property of the system and its differential is exact
Identify the wrong statement:
The laws of thermodynamics cannot be derived mathematically
The quantity of matter constituting a system remains constant
The kinetic and potential energies possessed by a system can be converted into heat
The system and its surroundings taken together constitute an isolated system
In case of power failure, a battery is used to light a bulb, run a fan and heat an electric iron (each of 100W rating) for 10 minutes. In this operation, the work done W and heat supplied Q by the battery are
W=0, Q=0
W=180kj, Q=0
W=60kj, Q=120kj
None of the above
An insulted rigid vessel contains some gas and an electric resistor. In certain interval of time, the resistance connected to an external electric power heats the gas. Considering the vessel and its contents as the system
Heat and work transfer are zero
Heat and work transfer are positive
Heat transfer is zero and work transfer is negative
Heat transfer is positive and work transfer is zero
For a system to be thermodynamic equilibrium the system and its surroundings are to be in
Thermal equilibrium
Chemical equilibrium
Mechanical equilibrium
Thermal and chemical equilibrium
Thermal, chemical and mechanical equilibrium
Which statement corresponds to zeroth law of thermodynamics?
Work can be completely converted into heat
Two systems in thermal equilibrium with a third system are in thermal equilibrium with each other
There can not be transfer of heat from a system at low temperature to another system at high temperature
It is practically impossible to attain a zero degree absolute temperature
Zeroth law of thermodynamics states that:
Two thermodynamics systems are always in thermal equilibrium with each other
If two systems are in thermal equilibrium, then the third system will also be in thermal equilibrium
Two systems not in thermal equilibrium with a third system are also not in thermal equilibrium with each other
When two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other
Zeroth law of thermodynamics forms the basis of ………measurement
Pressure
Temperature
Heat exchange
Work
Two blocks which are different states are brought into contact with each other and allowed to reach a final state of thermal equilibrium. The final temperature attained is specified by the ………of thermodynamics
Zeroth law
First law
Second law
Third
The absolute zero temperature corresponds to the condition when
All the substances exist only as solids
Volume of a gas reduces to zero
Kinetic energy of gas molecules becomes zero
No pressure is exerted by the gas
The molecular kinetic energy of a gas is proportional to
T
T3/2
T2
Where T is the absolute temperature
The boiling point of water on a thermometer scale P is marked as 130o P and the freezing point -20oP. what will be the reading on this scale corresponding to 60 degree on celcius scale?
60oP
70oP
90oP
110oP
The pressure exerted on the walls of a container by a gas is due to the fact that gas molecules
Stick to the walls of the container
Lose their kinetic energy
Get accelerated towards the wall
Change their moment due to collision with the wall
A stream of gas molecules, each of mass m are hitting a surface normally with velocity v and getting absorbed. If the number of molecules per unit volume is n, the pressure exerted on the surface would be
mnv2
mnv2
mnv2
2mnv2
Which is not correct in the context of a pure substance?
Has a uniform and invariable chemical composition
Its state can be completely specified if any two independent intensive properties are fixed
An equilibrium mixture of liquid and gaseous air is a poor substance
Water is a pure substance if it exists as a solid, liquid, vapour or any combination of these
In thermodynamic analysis, a pure substance is that which
Has no dissolved impurities
Consists of only a single species
May have a number of chemical species but the composition remains constant
Behaves as a perfect gas
At triple point of a pure substance
Liquid and vapour phases co-exist
Solid and vapour phases co-exist
Liquid and solid phases co-exist
Solid, liquid and vapour phases co-exist
Mathematically, a pure substance can be written as
p=f(T,v)
v=f(p, T)
T=f(p,v)
Any one of the above
None of the above
Heat and work are equivalent quantities which under certain conditions can be converted one into the other in the equivalent proportions:Q=W/J. for engineering calculations, the constant of proportionately, J equals
29.27 mkgf/kcal
287 mkgf/kcal
427 mkgf/kcal
848 mkgf/kcal
The expression p dv gives the measure of work done during
Non-flow reversible process
Steady flow reversible process
Open system and any process
Any system and any process
The work done equals p dv for
An irreversible process
Unrestricted expansion
Non-flow quasi-static process
The arrangement where work is done on the gas as the paddle wheel turns by a falling weight
Identify the wrong statement concerning thermodynamic work
W=p dv for a reversible process only
W=0 if dv=0
W?p dv for a free expansion process
Is a path function and has in exact differential
Which of the followings is not valid in the context of a quasi-static process?
Pressure is uniform and remains process practically constant
Friction is negligible and the process proceeds at infinitesimally small speed
Process takes place due to finite unbalanced potential within the system or between it and the surroundings
Process can be represented graphically as a continuous line on a state diagram
A quasi-static process is one in which all the states through which a system passes are very close to
Equilibrium state
Original state
Same temperature
Each other
All of the following statements are true for a quasi-static process except :
Proceeds very slowly
Can proceed in either direction
Need not abe a reversible process
Occurs when the driving force is finite but very small
Which of the following is a non-quasi static process?
Gradual compression of gas inside a piston-cylinders arrangement
Expansion of gas in a cylinder under constant pressure
Free or unrestricted expansion of gas
Rapid leakage of air from a bicycle tyre
First law of thermodynamics refers to conservation of
Mass
Momentum
Energy
Force
Which of the following statement does not represent the essence of first law of thermodynamics?
Heat input to a system equals the net work done plus change in internal energy
The sum of heat and work effects will be zero if the system undergoes a cycle
Heat input cannot be more than the work output
For an isolated system, energy remains constant
Mark the statement/ formulation which is wrong:
1st law is applicable to reversible as well as irreversible processes
Quartz clock works continuously and thus constitutes a perpetual motion machine of first kind
=
(is an exact differential even though Q and W are inexact differential .
In the context of a closed non-flow system, the net energy transferred as heat and work equals the change in
Enthalpy
Internal energy
Entropy
Flow work
For a closed system, the difference between heat added to and work done by the system is equal to
Enthalpy
Internal energy
Gibbs function
Flow work
The internal energy of an ideal gas is a function of
Pressure only
Absolute temperature only
Pressure and volume
Pressure, volume and temperature
The internal energy of an ideal gas is a function of its absolute temperature only.
This statement refers to
Avogadro’s law
Maxwell law
Joule’s law
Regnault’s law
The identify Q=p dv is true for
Any process and open system
Any process and closed system
Any process and any system
Reversible process and closed system
In a general compression process, 1kj of mechanical work is supplied to 2kg of fluid and 400 j of heat is rejected to the cooling jackt. The change in specific internal energy would be
700 j
350 j
300 j
600 j
A paddle wheel used for stirring a liquid contained in a tank supplies 5000 kJ of work and during the stirring operation the tank loses 1500 kJ of heat to the surroundings. If the tank and liquid are considered as a system, the change in its internal energy will be
1500 kJ
3500 kJ
5000 kJ
6500 kJ
A tank containing air is stirred by a paddle wheel. The work input to the paddle wheel is 9000 kJ and the heat transffered to the surroundings from the tank is 3000 kJ. The external work done by the system is
Zero
3000 kJ
6000 kJ
9000 kJ
When a system is taken from state point a to state point b along the path a-c-b, 80 kJ of heat flows into the system and it does 30 kJ of work. How much heat will flow into the system along path a-d-b if the work done by it along this path is 10 kJ?
20 kJ
40 kJ
60 kJ
80 kJ
Refer to cycle abcda executed by an ideal gas. The net work done during the cycle equals
Zero
pv
2pv
4pv
An ideal gas of mass m in state A expands to state point B via three paths. If Q1, Q2, Q3 represent the heat absorbed by the gas along these paths, then
Q1< Q2 Q1>Q2>Q3
Q1Q3
Q1>Q2 A closed system undergoes a thermodynamic cycle consisting of four separate and distinct processes. The heat transfer for each of the process is as given below:
1. No heat exchange
2. 20,000 kJ into the system
3. -2,000 out of the system
4. -6,000 out of the system
the thermal efficiency of the cycle will be
10%
30%
40%
60%
Choose the wrong statement
If a closed system tracks a cycle of operations, then dp is zero
is true only for reversible process and closed system
Internal energy is a property of the system
When a gas undergoes a free or unrestricted expansion, the W?p dv
Consider work done by an ideal gas when undergoing an expansion process. During this act, the temperature of the gas
Decreases only
Increases only
Increases or decreases
Remains constant
The values of heat transfer and work transfer for the flow processes of a thermodynamic cycle are given below:
Process Heat transfer
(kJ)Work transfer
(kJ)1.3003002.Zero2503.-100-1004.zero-250The thermal efficiency and work ratio for the cycle will be respectively
33% and 0.66
66% and 0.36
36% and 0.66
33% and 0.36
Heat is being supplied to air in a cylinder fitted with a frictionless piston held by a constant weight. The process is
Isothermal
Adiabatic
Isobaric
Isochoric
Under what conditions, the change in the enthalpy of a system equals the heat supplied?
Constant volume
Constant pressure
Constant temperature
Standard temperature pressure conditions
Which aspect is true in the context of an isochoric process?
No transfer of mass and energy
Product of pressure and volume remains constant
Free expansion takes place
Work output from the system is zero
An ideal gas is made to go from state A to state B in the following two different ways:
an asobaric and then an isochoric process
an isochoric and then an isobaric process
The work done by the gas in two cases is W1 respectively. Then
W1=W2
W1>W2
W1 W1=W2
The change in internal energy of a closed system during a certain reversible process equals the heat transferred if the process takes place at
Constant volume
Constant pressure
Constant temperature
Such a situation never arises
Heat supplied to a system equals the work done in case of a non-flow process carried out
Isochorically
Isobarically
Isothermally
Adiabatically
Which parameter remains constant during a reversible isothermal process?
Rate of heat exchange
Internal energy
Enthalpy
Entropy
Which of the following parameter changes during an isothermal process?
Pressure
Temperature
Internal energy
(pressure x specific volume)
Work output from a system is at the expense of internal energy is a non-flow process carried out
At constant pressure
At constant volume
Adiabatically
Polytropically
During an adiabatic process
Temperature of gas is varied but the pressure is kept constant
Total kinetic energy of the gas molecules remains constant
Gas is compressed at constant temperature and there is no change of entropy
Expansion and compression of a gas occur without any exchange of heat with the surroundings
For an adiabatic process, the pressure and volume are related as pvy= constant. The exponent y represents the ratio of specific heat at constant pressure to specific heat at constant volume and for air, its value equals
0.87
1.02
1.4
1.67
Which of the following is not a feature of the free expansion process?
Irreversible process
Non-quasistatic process
There is transfer of enegy to the system
Pressure and volume are not related through the equation of state
The gas with highest value of adiabatic index is
Helium
Nitrogen
Oxygen
Methane
For an adiabatic process, the temperature and pressure are related as; T2/T1=
(p2/p1)y-1
(p2/p1)1/y-1
(p2/p1)y-1/y
(p2/p1)y/y-1
During an adiabatic expansion process, the increase in volume is associated with
Decrease in both pressure and temperature
Increase in both pressure and temperature
Decrease in pressure and increase in temperature
Increase in pressure and decrease in temperature
Which one of the following characteristics does not change during a reversible adiabatic process?
Enthalpy
Entropy
Internal energy
Rate of heat exchange
Expension of hot gases in an I.C. engine can be approximated to an
Isothermal process
Adiabatic process
Isobaric process
Isochoric process
A gas at pressure p in the vessel is compressed suddenly to half of its original volume. Then pressure of the gas after a long time becomes
1/2p
2p
Less than 2p
Greater than 2p
During a general polytropic expansion process characterized by pvn=constant, the work done is equal to
P1v1-p2v2
P1v1 loge
The heat absorbed or rejected during a polytropic process (pvn=constant is
x work done
x work done
x work done
x work done
Isothermal and adiabatic processes are identical at
Saturation temperature
Critical temperature
Absolute zero temperature
Below 0oC temperature
For a closed system undergoing an expansion process, the work output
Increases with increase in n
Increases with decrease in n
Is maximum when n=0
Is independent of n
Consider a perfectly insulated container which has two compartments separated by a partition. One compartment contains a perfect gas and the other compartment is in a state of perfect vacuum. Upon removal of the partition, the gas expands and fills the whole space. Such an expansion process is referred to as
Adiabatic expansion
Isothermal expansion
Throttling
Free or unrestricted expansion
Which aspect does not pertain to a free expansion process?
No gain or loss of heat
Work done is zero
Pressure remains constant
No change in the temperature of the system
When a gas or vapour is allowed to escape through a minute aperature (i.e. leakage of steam through the safety valve of a pressure cooker), the leakage process is called
Constant pressure
Adiabatic
Throttling
Parabolic
Air is being forced by the bicycle pump into a tyre against a pressure of 4.5bar. A slow downward movement of the piston can be approximated as
Isobaric
Adiabatic process
Isothermal process
Throttling process
The value of exponent n= in the polytropic process pvn=c is indicative of
Throttling process
Isochoric process
Isobaric process
Isontropic process
Which parameter can be considered to remain constant if the value of exponent n in the poytropic equation pvn=constant takes a unit value?
Enthalpy
Entropy
Internal energy
Pressure or volume
A system at a given state undergoes change through the following expansion process to reach the same final volume
1. isotheramal
2. isobaric
3. adiabatic (y=1.4)
4. polytropic (n=1.2)
the correct ascending order of the work output in these four processes is
1, 2, 4, 3
1, 4, 3, 2
4, 1, 3, 2
4, 1, 2, 3
Give a correct match between the process listed in column A and the value of exponent n, in the relationship pvn=constant, listed in column B.
Column AColumn Badiabatic
isobaric
isochoric
isothermaaln=0
n=1
n=cp/cv=y
(1,c), (2,a), (3,d), (4,b)
(1,b), (2,c), (3,d), (4,a)
(1,a), (2,b), (3,c), (4,d)
(1,d), (2,a), (3,c), (4,d)
All of the following processes are identical regarding work output, except one process. Identify that process
Isochoric
Isothermal
Free expansion
Throttling
For obtaining maximum work in the act of a gas expanding in a closed system, the expansion process must take place at
Constant temperature
Constant pressure
Constant entropy
Constant enthalpy
Choose the wrong statement
For a quasi-static process, the work output is found to be maximum and work input minimum
The integral of p dv on a pressure-volume diagram is the area under the curve representing the quasi static process
The change in internal energy in a constant pressure process from temperature t1 to temperature t2 is given by mcp(t1-t2)
At a given temperature, the specific heat of a gas at constant pressure is always greater than its specific heat at constant volume
Neglecting changes in potential and kinetic energies, the shaft work during a steady flow process is given by
p dv
v dp
Pv
-h
For a reversible adiabatic compression in a steady flow process, the work transfer per unit mass is
p dv
v dp
T ds
s dT
Neglecting changes in kinetic and potential energies, the identity -v dp=h1-h2 for the shaft work during a steady flow process is valid for
Constant volume process
Reversible isothermal process
Reversible adiabatic process
Reversible polytropic process
A perpetual motion of first kind is represented by
Fully reversible engine
An engine with 100 per cent thermal efficiency
A machine that continuously creates its own energy
A machine that is capable of transferring heat energy from a system at low temperature to a system at high temperature
Which is the essence of second law of thermodynamics?
The whole of heat supplied to a system can be converted into equivalent mechanical work
No engine can be 100 per cent efficient
A refrigerator can reduce the temperature to absolute zero
Reversible engines working between the same temperature limits can have different thermal efficiencies
“Heat can not be transported from a system at low temperature to another system external agency”. This statement of second law is attributed to_____
Gay lusac
Clausius
Max-planck
Joule Thomson
Which condition will not contribute towards a process to be reversible?
There should be no friction;solid or flouid
Heat must be transferred only through an infinitely small temperature difference
The process must proceed in a series of equilibriaum states
The process must be accomplished quickly
Which of the following processes can approach reversibility?
Mixing of different substances
Chemical reactions
Controlled or restricted expansion or compression
Action of brakes in stopping a vehicle
The processes involved in a carnot cycle are:
Two adiabatic processes and two constant volume processes
Two adiabatic processes and two isothermal processes
Two isothermal and two constant pressure processes
Two constant pressure and two constant volume processes
In a carnot cycle, the rejection of heat is
At constant pressure
At constant volume
At constant temperature
Partly at constant pressure and partly at constant volume
The efficiency of a carnot cycle engine depends on
Speed of the engine
Working fluid; whether gas or vapour
Temperature at which heat is supplied and that at which it is rejected
Temperature of ambient air
A carnot cycle will be 100 per cent efficient if
The engine is made to run at infinitely high speeds
The working fluid is a pure substance
The source and sink temperatures are 500oC respectively
The rejection of heat is at 0oK temperature, whatever may be the temperature of source
Which aspect is not true in the context of the efficiency of a carnot cycle engine?
Depends upon the temperature of source and sink
Is always less than 100 per cent
Is same for all reversible engines working between the same temperature limits
Is dependent on the working fluid
The carnot cylcle is impracticable because it
Requires a perfect gas as the working fluid
Necessitates all processes comprising the cycle to be reversible
Demands high speeds for its working
Involves greater pressures and volumes
For a heat engine operating on carnot cycle, the work output is 1/4th of the heat rejected to the sink. The thermal efficiency of the engine would be
10%
20%
30%
50%
A heat engine is supplied with 260 kJ/s of heat at a constant fixed temperature of 520 K and heat rejection takes place at 260 K temperature. If the engine is reversible, the heat rejected would be approximately equal to
85 kJ/s
110 kJ/s
130 kJ/s
155 kJ/s
Three engines A, B and C operating on carnot cycle respectively use air, steam and helium as the working fluid. If all the engines operate within the same high and low temperature limits, then which engine will have the highest efficiency?
Engine A
Engine B
Engine C
All engines will have the same efficiency
If the thermal efficiency of a carnot heat engine is 40 percent, then coefficient of performance of a refrigerator working within the same temperature limits would be
1.5
2.5
3.5
4.5