Chapters 1 (THERMODYNAMICS) Flashcards
Enthalpy of an ideal gas is a function only of ________
Temperature
Which of the following is the most efficient thermodynamic cycle?
Carnot
What is the first law of thermodynamics?
Energy can neither be created nor destroyed
An ideal gas is compressed isothermally. What is the enthalpy change?
Zero
Name the process that has no heat transfer.
Adiabatic
An ideal gas is compressed in a cylinder so well insulated that there is essentially no heat transfer. The temperature of the gas
Increases
What is the Sl unit of pressure?
Pascal
The equation Cp = Cv + R applies to which of the following?
Ideal gas
In the flow process, neglecting kinetic and potential energies, the integral of Vp represents what ?
Shaft work
Mechanical energy of pressure transformed into energy of heat.
Enthalpy
The theory of changing heat into mechanical work.
Thermodynamics
Average pressure on a surface when a changing pressure condition exist.
Mean effective pressure
Which of the following cycles consist two isothermal and two constant volume processes?
Stirling cycle
A control volume refers to what?
A fixed region in space
In the polytropic process, PV^n = constant, if the value of n is infinitely large, the process is
Isometric
If the temperature is held constant and the pressure is increased beyond the saturation pressure, then the working medium must be:
compressed liquid
Is one whose temperature is below the saturation temperature corresponding to its pressure
Subcooled liquid
Number of molecules in a mole of any substance is a constant is called
Avogadro’s number
If the pressure of a gas is constant the volume directly proportional to the absolute temperature
Charles’ Law
The number of protons in the nucleus of an atom or number of electrons in the orbit of an atom
Atomic number
In a P-T diagram of a pure substance, the curve separating the solid phase from the liquid phase is:
Fusion curve
A water temperature of 18 °F in the water cooled condenser is equivalent in °C to
10
The latent heat of vaporization in Joules per kg is equal to
22.6 x 10^5
Form of energy associated with the kinetic energy of the random motion of large number of molecules
Heat
If the temperature is held constant and the pressure is increased beyond the saturation pressure, then, the working medium must be:
Compressed liquid
Is the condition of pressure and temperature at which a liquid and its vapor are indistinguishable
Critical Point
When a substance in gaseous state is below the critical temperature, it is called
Vapor
Superheated vapor behaves
Approximately as a gas
Which of the following provides the basis for measuring thermodynamic property of temperature?
Zeroth Law of thermodynamics
Which of the following is commonly used as liquid absorbent
Ethylene glycol
Mechanism designed to lower the temperature of air passing through it.
Air cooler
A device for measuring the velocity of wind.
Anemometer
Heat normally flowing from high temperature body to a low temperature body wherein it is impossible to convert heat without other effects.
Second law of thermodynamics
The temperature at which its vapor pressure is equal to the pressure exerted on the liquid
Boiling point
A nozzle is used to
Increase velocity and decrease pressure
The sum of the energies of all the molecules in a system where energies appear in several complex form.
Internal energy
The total energy in a compressible or incompressible fluid flowing across any section in a pipeline is function of
Flow energy, kinetic energy, height above datum and internal energy
The ratio of the density of a substance to the density of some standard substance
Specific gravity
Is one whose pressure is higher than a saturation pressure corresponding to its temperature
Compressed liquid
The changing of solid directly to vapor without passing through the liquid state is called
Sublimation
Weight per unit volume is termed as
Weight density
What is the S1 unit of force?
Newton
The volume of fluid passing a cross-section of steam in unit time.
Discharge
What equation applies in the first law of thermodynamics for an ideal gas in a reversible open steady-state system?
Q + VdP = H2 – H1
A pressure of 1 millibar is equivalent to
1000 dynes/cm^2
When a system deviates infinitesimally from equilibrium at every instant of its state, it is undergoing:
quasi-static process
What is the force which tends to draw a body toward the center about which it is rotating?
Centripetal force
What is the process that has no heat transfer?
Adiabatic
Which of the engine is used for fighter bombers
Turbojet
Exhaust gases from an engine posses:
Kinetic Energy
A critical point the latent enthalpy of vaporization is
Zero
What is the force which tends to draw a body towards the center about which it is rotating?
Centripetal force
When a system deviates and infinitesimally from equilibrium at every instant of its state, it is undergoing
quasi- static process
Work done per unit charge when charged is moved from one point to another
Potential at a point
How many independent properties are requires to completely fix the equilibrium state of a pure gaseous compound?
2
Which of the following relations defines enthalpy?
h = u + pV
Which of the following is true for water at a reference temperature where enthalpy is zero?
Internal Energy is negative
On what plane is the Mollier diagram plotted?
h-s
The compressibility factor z, is used for predicting the behavior of non - ideal gases. How is the compressibility factor defined relative to an ideal gas? ( subscript c refers to critical value )
z= PV/RT
How is the quality x of a liquid - vapor mixture defined?
The fraction of the total mass that is saturated vapor
What is the expression for heat of vaporization?
hg-hf
What is the value of the work done for a closed, reversible, isometric system?
Zero
What is the equation for the work done by a constant temperature system?
W = MRT In (V2/V1)
What is true about polytropic exponent n for a perfect gas undergoing an isobaric process?
n = 0
How does an adiabatic process compare to an isentropic process?
Both: Heat transfer = 0; Isentropic: Reversible
During an adiabatic, internally reversible process, what is true about the change in entropy?
It is always zero
For an irreversible process, what is true about the change in entropy of the system and surroundings?
ds > 0
For which type of process does the equation dQ = Tds hold?
Reversible
Which of the following is true for any process?
∆S (Surrounding) + ∆S (system) ≥ 0
Which of the following thermodynamics cycle is the most efficient?
Carnot
The ideal reversible Carnot cycle involves four basic processes. What type of processes are they?
Two isothermal and two isentropic
What is the temperature difference of the cycle if the entropy difference ∆S, and they work done is W?
W / ∆S
Which of the following is not an advantage of a superheated, closed Rankine cycle over an open Rankine cycle?
Increased boiler life
Which of the following statements regarding Rankine cycle is not true?
In practical terms, the susceptibility of the engine materials to corrosion is not a key limitation on the operating efficiency
Which one of the following is standard temperature and pressure (STP)
0 °C and 1 atm pressure
A substance is oxidized when which of the following occurs?
it losses electrons
Which of the following is not a unit of pressure?
kg / m-s
Definition of Joule
Newton meter
Which of the following is the basis for Bernoulli’s law for fluid flow?
The principle of conservation of energy
Equation of state for a single component can be any of the following except:
A. the ideal gas law
B. any relationship interrelating 3 or more state functions
C. relationship mathematically interrelating
thermodynamic properties of the material
D.A mathematical expression defining a path between states
A mathematical expression defining a path between states
The state of a thermodynamic system is always defined by its:
properties
In any non quasi-static thermodynamic process, the overall entropy of an isolated system will
increase only
Entropy is the measure of :
randomness or disorder
Which of the following statements about entropy is
Entropy of a crystal at 0 °F is zero
Work or energy can be a function of all of the following except :
force and distance
power and time
force and time
temperature and entropy
force and time
Energy changes are represented by all except which one of the following:
dQ / T
U + pV is a quantity called :
enthalpy
In flow process, neglecting KE and PE changes, JvdP represents which item below?
Shaft work
Power may be expressed in units of
Btu / hr
Equilibrium condition exist in all except which of the following?
In a steady state flow process
In a closed system (with a moving boundary) which of the following represents work done during an isothermal process?
W= P1 V1 ln V2 / V1
A substance that exists, or is regarded as existing, as a continuoum characterized by a low resistance to flow and the tendency to assume the shape of its container.
Fluid
A substance that is homogeneous in composition and homogeneous and invariable in chemical aggregation.
Pure substance
A substance whose state is defined by variable intensive thermodynamic properties.
Simple substance
A system in which there is no exchange of matter with the surrounding or mass does not cross its boundaries.
Closed System
A system that is completely impervious to its surrounding or neither mass nor energy cross its boundaries.
Isolated system
A system in which there is a flow of mass across its boundaries
Open system
The properties that are dependent upon the mass of the system and are total values such as total volume and total internal energy.
Extensive properties
The properties that are independent of the mass of the system such as temperature, pressure, density and voltage.
Intensive properties
The properties for a unit mass and are intensive by definition such as specific volume.
Specific Properties
The condition as identified through the properties of the substance, generally defined by particular values of any two independent properties.
State
The only base unit with a prefix kilo is
kilogram
The force of gravity on the body.
Weight
The mass per unit volume of any substance
Density
The force of gravity on unit volume is
specific weight
The reciprocal of density is
Specific volume
Avogadro’s number, a fundamental constant of nature, is the number of molecules in a gram-mole. This constant is
6.02252 x 10^23
The ratio of the gas constant to Avogadro’s number is:
Boltzmann’z constant
The absolute zero on the Fahrenheit-scale is at
–459.7 °F
Absolute temperatures on the Fahrenheit scale are called:
Degrees Rankine
The absolute zero on the Celsius scale is at
-273.15 °C
What is the absolute temperature in celsius scale?
degrees Kelvine
The Fahrenheit scale was introduced by Gabriel Fahrenheit of amstermdam, Holland in what year?
1720
The Centigrade scale was introduced by Anders Celsius in what year?
1740
The National Bureau of Standards uses, among others, the liquid - vapor equilibrium of Nitrogen at
–196 °C
The liquid - vapor equilibrium of Oxygen is at what temperature?
-182.97 °C
The solid- liquid equilibrium of Mercury is at what temperature?
-38.87 °C
The national Bureau of standards uses, among others, the liquid- vapor equilibrium of hydrogen at
–253 °C
The solid- liquid equilibrium of Tin is at what temperature?
231.9 °C
The solid-liquid equilibrium of Zinc is at what temperature?
419.505 °C
The liquid-vapor equilibrium of sulfur is at what temperature?
444.60 °C
The solid-liquid equilibrium of Antimony is at what temperature?
630.5 °C
The solid liquid equilibrium of silver is at what temperature?
960.8 °C
the solid-liquid equilibrium of Gold is at what temperature?
1063 °C
The solid-liquid equilibrium of Platinum is at what temperature?
1774 °C
The solid-liquid equilibrium of Tungsten is at what temperature!
3370 °C
The device that measures temperature by the electromotive force.
thermocouple
The emf is a function of the temperature difference between the junction, a phenomenon called :
Seebeck effect
A device that measure temperature by the electromotive force called thermocouple was discovered by :
Seebeck
When two bodies, isolated from other environment, are in thermal equilibrium with a third body, the two are in thermal equilibrium with each other.
Zeroth law of thermodynamics
The total entropy of pure substances approaches zero as the absolute thermodynamic temperature approaches zero.
Third law of thermodynamics
If any one or more properties of a system change, the system is said to have undergone a
process
When a certain mass of fluid in a particular state passes through a series of processes and returns to its initial state, it undergoes a :
cycle
The term given to the collection of matter under consideration enclosed within a boundary
System
The region outside the boundary or the space and matter external to a system
Surrounding
The true pressure measured above a perfect vacuum
Absolute pressure
The pressure measured from the level of atmospheric pressure by most pressure recording instrument like pressure gage and open ended manometer
Gage pressure
The pressure obtained from barometric reading
Atmospheric pressure
It is a form of energy associated with the kinetic random motion of large number of molecules
Heat
The heat needed to change the temperature of the body without changing its phase
Sensible heat
The heat needed by the body to change its phase without changing its temperature
Latent heat
The measure of the randomness of the molecules of a substance
Entropy
The heat energy transferred to a substance at a constant pressure process is
enthalpy
It is the energy stored within the body
Internal energy
A theoretically ideal gas which strictly follows Boyle’s law and Charle’s law of gases
Perfect gas
In a confined gas, if the absolute temperature is held constant, the volume is inversely proportional to the absolute pressure
Boyle’s Law
In a confined gas if the absolute pressure is held constant the volume is directly proportional to the absolute temperature.
Charles law
The pressure exerted in a vessel by a mixture of gases is equal to the sum of the pressures that each separate gas would exert if it alone occupied the whole volume of the vessel.
Dalton’s law
At equal volume, at the same temperature and pressure conditions, the gases contain the same number of molecules.
Avogadro’s law
A process which gives the same states/conditions after the system undergoes a series of processes :
Cyclic process
A thermodynamic system that generally serves as a heat source or heat sink for another system.
Heat reservoir
A thermodynamic system that operates continuously with only energy (heat and work) crossing its boundaries; its boundaries are impervious to the flow
of mass.
Heat engine
A surface that is impervious to heat is
adiabatic surface
One of the consequences of Einstein’s theory of relativity is that mass may be
converted into energy and energy into mass, the relation being given by the famous equation, E = mc^2. What is the value of the speed of light c?
2.9979 x 10^10 cm/s
In the polytropic process we have pv = constant, the value of n is infinitely large, the process is called
constant volume process
The thermodynamic cycle used un a thermal power plant is :
Rankine
Fo the same heat input and same compression ratio :
efficiency depends mainly on working substance
A heat exchange process where un the product of pressure and volume remains constant called :
hyperbolic process
Which of the following provides the basis for measuring thermodynamics property of temperature?
Zeroth law of thermodynamics
1 watt
1 Nm/s
Under ideal conditions, isothermal al, isobaric, isochoric and adiabatic processes are :
quasi-static processes
Isentropic flow is
reversible adiabatic flow
Exhaust gases from an engine possess
kinetic energy
The extension and compression of a helical spring is an example of what process?
reversible process
At critical point the latent enthalpy of vaporization is
zero
Which of the following relations is not applicable in a free expansion process?
Change in temperature is zero
The triple point of a substance is the temperature and pressure at which :
the solid does not melt, the liquid does not boil and the gas does not condense
According to Clausius statement :
A. Heat flows from hot substance to cold substance, unaided
B. Heat cannot flow from cold substance to hot substance
C. Heat can flow from cold substance to hot substance with the aid of external work
D. A and C
A and C
A heat is supplied heat at rate of 30 000 J/s gives an output of9 kW. The thermal efficiency of the engine is
30%
The RMS velocity of hydrogen gas at N.T.P is approximately
1839 m/s
“It is impossible to construct a heat engine that operates in a cycle and receives a given quantity of heat from a high temperature body and does an equal amount of work” The above statement is known as :
Kelvin - Planck’s law
For steam nozzle, which of the following ratios will have the value less than unity?
Specific volume at inlet / (Specific volume outlet)
A Bell- Coleman cycle is a reversed
Joule cycle
Ericsson cycle consists of the following processes:
two isothermal and two constant pressure
A steam nozzle changes
heat energy into kinetic energy
Which is not correct for calculating air standard efficiency?
Gases dissociate at higher temperatures
According to Pettlier Thomson effect:
Work can’t be converted to heat
In actual gases the molecular collisions are:
inelastic
The Beattie-Bridgeman equation of state is quite accurate in cases of:
densities less than about 0.8 times the critical density
Which of the following statement about Vander Waals equation is correct?
It has three roots of identical value at the critical point
The Clayperon’s equation is applicable to :
a change of state when two phases are in equilibrium
The vapor pressure is related to the enthalpy of vaporization by the:
Clausius-Claypeyron’s ewuation
Solubility of a gas in a liquid at small concentration can be represented by which law?
Henry’s law
A compound pressure gauge is used for to measure:
positive and negative pressures
Which of the engine is used for fighter bombers?
Turbojet
The thermal efficiency of gas-vapor cycle as compared to steam turbine or gas turbine
greater than
The process in which heat energy is transferred to thermal energy storage device is known as:
regeneration
The absolute zero in Celsius scale is:
-273
What is the temperature when water and vapor are in equilibrium with the atmospheric pressure?
Steam point
The temperature of a pure substance at a temperature of absolute zero is:
zero
When the number of reheat stages in a reheat cycle is increased, the average temperature :
increases
The temperature measurement in an ordinary thermometer which has constant specific humidity.
Dew point temperature
In a closed vessel, when vaporization takes place, the temperature rises. Due to the rising temperature, the pressure increases until an equilibrium is established between the temperature and pressure. The temperature of equilibrium is called :
Boiling point
When hot soup was served in a cup during dinner an engineer was so eager to drink it. Since it was hot, he added cubes of ice to cool the soup and stirred it. He noticed that dew starts to form on the outermost surface of the cup. What is this temperature equal to?
equal to air’s dew point temperature
Is a measure of the energy that is no longer available to perform useful work within the current environment
Absolute entropy
A graph of enthalpy versus entropy for steam
Mollier diagram
The reaction of inertia in an accelerated body is called
Kinetic reaction
A Mollier chart of thermodynamic properties is shown in which of the following diagrams?
h-S diagram
The following are included in the first law thermodynamics for closed system EXCEPT :
Internal energy
All processes below are irreversible except one. Which one?
Elastic tension and release of a steel bar
The combination of conditions that best describes thermodynamics process is given by which of the following?
Has successive states through which the system passes
The sum of the energies of all the molecules in a system where energies appear in several complex forms is the:
internal energy
The Carnot refrigeration cycle includes all of the following process except:
isenthalpic expansion
The maximum possible work that can be obtained cycle operating between two reservoirs is found from
Carnot efficiency
The following factors are necessary to define thermodynamic cycle except
the time it takes to complete the cycle
All of the following terms included in the second for open system except
Average work
The following terms are included in the first law of thermodynamics for open systems except
magnetic system
The following terms are included in the first law of thermodynamics for closed systems except:
kinetic energy
Which of the following statements about a path function is not true?
It represents values of p,v,t and s between states that are path functions
A constant pressure thermodynamic process obeys:
Charles Law
The first and second laws of thermodynamics are:
energy equations
Represents the temperature an ideal gas will attain when it is brought to rest adiabatically
Stagnation temperature
Gauge pressure and absolute pressure differ from each other by:
atmospheric pressure
Each of the following are correct values of standard atmospheric pressure except:
1013mm Hg
All of the following are properties of an ideal gas except:
Viscosity
Which of the following is not the universal gas constant?
8314 J/mol.K
The following are all commonly quoted values of standard temperatures and pressure except:
0 °F and 29.92 in Hg
The variation of pressure in an isobaric process is
zero
For fluid flow, the enthalpy is the sum of internal energy and
work flow
A thermodynamic process whose deviation from equilibrium is infinitesimal at all time is
in quasi-equilibrium
Which thermodynamic property best describes the molecular activity of a substance
Internal energy
Stagnation enthalpy represents the enthalpy of fluid when it is brought to rest
adiabatically
During stagnation process, the kinetic energy of a fluid is converted to enthalpy which results in an:
increase in the fluid temperature and pressure
The properties of fluid at the stagnation in state are called
stagnation state
All of the following are thermodynamic properties except
modulus of elasticity
A liquid boils when its vapor pressure equals
the ambient pressure
A system composed of ice and water at 0 °C is said to be:
A. a multiple material
B. in thermodynamic equilibrium
C. in thermal equilibrium
All of the above
The heat of fusion of a pure substance is:
the energy required to melt the substance
The heat of vaporization involves the change in enthalpy due to :
the change in phase from liquid to gas
The heat of sublimation involves the change in enthalpy due to :
the change in phase from solid to gas
A specific property
defines a specific variable ( e.g temperature)
A material’s specific heat can be defined as :
all of the above
If a substance temperature is less than its saturation temperature, the substance is :
Subcooled liquid
If a substance temperature is equal to its saturation temperature, the substance is
saturated liquid and vapor
If a substance’s temperature is greater than saturation temperature, the substance is a
superheated vapor
Critical properties refer to
property values where liquid and gas phase are indistinguishable
For the saturated vapor, the relationship between temperature and pressure is given by:
the steam table
Properties of a superheated vapor are given by
a superheated table
Properties of non-reacting gas mixtures are given by
volumetric weighting for molecular weight and density and geometric weighting for all other properties except entropy
The relationship between the total volume of a mixture of non- reacting gases and their partial volume is given by
Amagat’s law
The relationship between the total pressure of a mixture of non reacting gases and the partial pressures of constituents is given by
Dalton’s law
Which of the following is the best definition of enthalpy?
The amount of useful energy in a system
Which of the following statements is not true for real gases?
Real gases are found only rarely in nature
The stagnation state is called the isentropic stagnation state when the stagnation process is:
reversible as well as adiabatic
The entropy of a fluid remains constant during what process?
isentropic stagnation process
All of the following processes are irreversible except
an isentropic deceleration of a moving perfect fluid
All of the following processes are irreversible except:
an isentropic compression of a perfect gas
All of the following processes are irreversible except
elastic tension and release of a steel bar
Which of the following state(s) is/are necessary for a system to be in thermodynamic equilibrium?
Chemical, mechanical, and thermal equilibrium
Adiabatic heat transfer within a vapor cycle refers to:
The transfer of energy from one steam to another in a heat exchanger so that the energy of the output streams
Which of the following gives polytropic under n?
A = log P2/P1 / log V1/V2
The work done in an adiabatic process in a system?
is equal to the change in total energy of a closed system plus net heat transfer
Based on the first law of thermodynamics, which of the following is wrong?
The heat transfer cannot exceed the work done
Assuming real processed, the net entropy change in the universe:
is positive
Which of the following types of flowmeters is most accurate?
Pitot tube
What if referred by control volume?
Fixed region in space
What is the most efficient thermodynamic cycle?
Carnot
How do you treat a statement that is considered a scientific law?
Accept aa a summary of experimental observation
An instrument commonly used in most research and engineering laboratories because it is small and fast among the other thermometers
Thermocouple
In an actual gases, the molecular collisions are
inelastic
Which of the following is used in thermal power plant?
Rankine
The elongation and compression of a helical spring is an example of
reversible process
Otto cycle consists of
Two isentropic and two constant volume processes
Brayton cycle has
Two isentropic and two constant pressure processes
A bell- Coleman cycle is a reversee
Joule cycle
A steam nozzle changes
heat energy into kinetic energy
The pilot tube is a device used for measurement of
velocity
The continuity equation is applicable to
Conservation of mass
The work done by force of R Newtons moving in a distance of L meters is converted entirely into kinetic energy and expressed by the equation:
RL= 1/2 MV^2
Gas being heated at constant volume is undergoing the process of:
isometric
Dew point is defined as
The temperature to which the air must be cooled constant pressure to produce saturation
What do you call the changing of an atom of element with a different atomic mass?
Atomic transmutation
What do you call the weight of the column of air above the earth’s surface?
Atmospheric pressure
What keeps the moisture from passing through the system?
Dehydrator
What condition exists in an adiabatic throttling process?
Enthalpy is constant
The specific gravity of a substance is a ratio of its density to the density of:
water
A compound pressure gauge is used to measure:
positive and negative pressures
Isentropic flow is
reversible adiabatic flow
Under ideal conditions, isothermal, isobaric, isochoric and adiabatic processes are:
quasi-static processes
One watt is
1 N.m/s
A temperature above which a given gas cannot be liquefied
Critical temperature
The effectiveness of a body as a thermal radiator at a given temperature
Emissivity
Which if the following occurs in a reversible polytropic process?
Some heat transfer occurs
The instrument used to measure atmospheric pressure is
Barometer
A pneumatic tool is generally powered by
air
Which of the following gases can be used to measure the lowest temperature?
Helium
The triple point of a substance is the temperature and pressure at which:
The solid does not melt, the liquid does not boil and the gas does not condense
Which of the following relations is not applicable in a free expansion process?
Change in temperature is zero
Ericsson cycle has
Two isothermal and two constant pressure processes
A stirling cycle has
Two isothermal and two constant volume processes
The temperature of the fluid flowing under pressure through a pipe is usually measured by;
A. a glass thermometer
B. an electric resistance thermometer
C. a thermocouple
all of the above
Specific heat capacity in an SI derived unit described as
kJ/ kgK
Which of the following is mathematically thermodynamics property?
A point function
When the expansion or compression of gas takes place “without transfer of heat” to or from the gas, the process is called:
adiabatic
Another name for the liquid valve is:
King valve
A liquid whose temperature is lower than the saturation temperature corresponding to the existing pressure
Subcooled liquid
The law that states “Entropy of all perfect crystalline solids is zero at absolute zero temperature
Third law of thermodynamics
What should be the temperature of both water and steam whenever they are present together?
Saturation temperature for the existing pressure
A manometer is an instrument that is used to measure:
air pressure
What is the area under the curve of a temperature entropy diagram?
Heat
What do bodies at temperature above absolute zero emit?
Thermal radiation
In the absence of any irreversibilities, a thermo electric generator, a device that incorporates both thermal and electric effects, will have efficiency of a/an
Carnot cycle
Both Stirling and Ericson engines are
external combustion engines
Nozzles does not involve any work interaction. The fluid through this device experiences
no change in potential energy
If the actual kinetic energy of a nozzle is Ka and Ki is the maximum value that can be attained by an isentropic expansion from an initial to final state, then the efficiency of the nozzle is:
Ka / Ki
The convergent section of a nozzle increases the velocity of the flow of the gas. What does it to do on its pressure?
It decreases the pressure
In a closed vessel, when vaporization takes place, the temperature rises. Due to the rising temperature, the pressure increases until an equilibrium is established between the temperature and pressure. The temperature of equilibrium is called
boiling point
At steam point, the temperatures of water and its vapor at standard pressure are:
in equilibrium
When hot soup was served in a cup during dinner, an engineer was so eager to drink it. Since it was hot, he added cubes of ice to cool the soup and stirred it. He noticed that dew starts to form on the outermost suriace of the cup. He wanted to check the temperature of the outermost surface of the cup. What is this temperature equal to?
Equal to air’s dew point temperature
What do you call a conversion technology that yields electricity straight from sunlight without the aid of a Working substance like gas or steam without the use of any mechanical cycle?
Photovoltaic-energy conversion
Which of the following property of liquid extend resistance to angular or shear deformation
Viscosity
What is the pressure at the exit of a draft tube in a turbine
Atmospheric
When changes in kinetic energy of a compressed gas are negligible or insignificant, the work input to an adiabatic compressor is
equal to change in enthalpy
What is the area under the curve of a pressure volume diagram
Nonflow work
In Stirling and Ericson cycle, regeneration can
increase efficiency
The first law of thermodynamics is based on which of the following principles?
Conservation of energy
In a two-phase system, 30% moisture means
70% vapor, 30% liquid
At 101.325 kPa, the boiling point of water is 100 C, If the pressure is decreased the boiling temperature will:
decrease
Which of the following is equivalent to 1Hp in Btu/hr?
2545
What is the pressure above zero?
Gage pressure
One Newton -meter is equal to:
1 Joule
Which of the following is the instrument used to measure fluid velocity?
Pitot tube
Cryogenic temperature ranges from:
-250 ° F to -459 °F
Steam at 2kPa is saturated at 17.5 °. In what state will the state be at 40 °C if the pressure is 2.0 kPa?
Superheated
Acceleration is proportional to force
Newtons law
Which of the following could be defined a simply push and pull?
Force
The true pressure measured above a perfect vacuum is:
absolute pressure
If an initial volume of an ideal gas is compressed to one -half its original volume and to twice its original temperature, the pressure:
quadruples
When the expansion or compression of gas takes place without transfer of heat to or from the gas, the process is called:
adiabatic process
The body radiates heat proportional to the fourth power of its absolute temperature
Stefan-Boltzmann law
All substances emit radiation, the quantity and quality of which depends upon the absolute temperature and the properties of material, composing the radiating body.
Planck’s law
For bodies in thermal equilibrium with their environment, the ratio of total emissive power to the absorptivity is constant at any temperature
Kirchhoff’s law
