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Worksheetsthermo
Total questions: 102
Worksheet time: 13mins
Enthalpy of an ideal gas is a function only of
entropy
internal temperature
temperature
pressure
Which of the following is the most efficient thermodynamic cycle?
brayton
otto
carnot
diesel
What is the first law of thermodynamics?
internal energy is due to molecular motions
entropy of the universe is increased by irreversible processes
energy can neither be crated nor destroyed
heat energy cannot be completely transformed into work
An ideal gas is compressed isothermally, what is the enthalpy change?
always negative
always positive
zero
undefined
Name the process that has no heat transfer.
isothermal
isobaric
Polytropic
adiabatic
An ideal gas is compressed in a cylinder so well insulated that there is essentially no
heat transfer. The temperature of the gas
decreases
increases
remain constant
is zero
What is the SI unit of pressure?
𝑘𝑔/cm²
𝑑𝑦𝑛𝑒𝑠/cm2
Pascal
Psi
The equation 𝐶𝑝 = 𝐶𝑣 + R applies to which of the following?
enthalpy
ideal gas
two phase state
all pure substances
In the flow process, neglecting kinetic and potential energies, the integral of Vdp represents what?
heat transfer
flow energy
enthalpy change
shaft work
Mechanical energy of pressure transformed into energy of heat.
kinetic energy
enthalpy
heat exchanger
heat of compression
The theory of changing heat into mechanical work.
thermodynamics
kinematics
inertia
kinetics
Average pressure on a surface when a changing pressure condition exist.
back pressure
partial pressure
pressure drop
mean effective pressure
Which of the following cycles consists two isothermal and two constant volume processes?
diesel cycle
Ericson cycle
Stirling cycle
Otto cycle
A control volume refers to what?
a fixed region in space
a reversible process
an isolated system
a specified mass
In the polytropic process, 𝑃𝑉𝑛 = constant, if the value of n is infinitely large, the process is
isobaric
isometric
isothermal
polytropic
If the temperature is held constant and the pressure is increased beyond the saturation pressure, then the working medium must be:
compressed liquid
sub cooled liquid
saturated vapour
saturated liquid
Is one whose temperature is below the saturation temperature corresponding to its pressure.
super heated vapor
wet vapor
sub cooled liquid
saturated liquid
Number of molecules in a mole of any substance is a constant called
Rankine constant
Avogadro’s number
Otto cycle
Thompson constant
If the pressure of a gas is constant the volume is directly proportional to the absolute temperature.
Boyle’s law
Joule’s law
Charle’s law
Kelvin’s law
The number of protons in the nucleus of an atom or the number of electrons in the orbit of an atom.
atomic volume
atomic number
atomic weight
atomic mass
In a P-T diagram of a pure substance, the curve separating the solid phase from the liquid phase is:
vaporization curve
fusion curve
boiling point
sublimation point
A water temperature of 18 °F in the water cooled condenser is equivalent in °C to
7.78
10
263.56
-9.44
The latent heat of vaporization in joules per kg is equal to
5.4x10 2
4.13x10³
22.6x10 5
3.35x10 5
Form of energy associated with the kinetic energy of the random motion of large number of molecules.
internal energy
kinetic energy
heat of fusion
heat
If the temperature is held constant and the pressure is increased beyond the saturation pressure, then the working medium must be:
saturated vapor
compressed liquid
saturated liquid
sub cooled liquid
Is the condition of pressure and temperature at which a liquid and its vapor are indistinguishable.
critical point
dew point
absolute humidity
relative humidity
When a substance in gaseous state is below the critical temperature, it is called
vapor
cloud
cloud
steam
Super heated vapour behaves
just as gas
just as steam
just as ordinary vapor
approximately as gas
Which of the following provides the basis for measuring thermodynamic property of temperature?
zeroth law of thermodynamics
first law of thermodynamics
second law of thermodynamics
third law of thermodynamics
Which of the following is commonly used as liquid absorbent?
silica gel
activated alumina
ethylene glycol
none of these
Mechanism designed to lower the temperature of air passing through it.
air cooler
air defense
air spill ove
air cycle
A device for measuring the velocity of wind.
aneroid barometer
anemometer
anemoscope
anemograph
Heat normally flowing from a high temperature body to a low temperature body where in it is impossible to convert heat with out other effects.
first law of thermodynamics
second law of thermodynamics
third law of thermodynamics
zeroth law of thermodynamics
The temperature at which its vapour pressure is equal to the pressure exerted on the liquid.
absolute humidity
calorimeter
boiling point
thermal point
A nozzle is used to
increase velocity and decrease pressure
decrease velocity as well as pressure
increase velocity as well as pressure
decrease velocity and increase pressure
The sum of energies of all the molecules in a system where energies appear in several complex form.
kinetic energy
potential energy
internal energy
frictional energy
The total energy in a compressible or incompressible fluid flowing across any section in a pipeline is a function of
pressure and velocity
pressure, density and velocity
pressure, density, velocity and viscosity
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.
relative density
specific gravity
specific density
relative gravity
Is one whose pressure is higher than the saturation pressure corresponding to its temperature.
compressed liquid
saturated liquid
saturated vapor
super heated vapor
The changing of solid directly to vapour without passing through the liquid state is called.
evaporation
vaporation
sublimation
condensation
Weight per unit volume is termed as
specific gravity
density
weight density
specific volume
What is the SI unit of force?
pound
Newton
Kilogram
Dyne
The volume of fluid passing a cross-section of steam in unit time
steady flow
discharge
Dyne
What equation applies in the first law of thermodynamics for an ideal gas in a reversible open steady-state system?
Q – W = 𝑈2 - 𝑈1
Q + VdP = 𝐻2 - 𝐻1
Q – VdP = 𝑈2 - 𝑈1
Q – PdV = 𝐻2 - 𝐻1
A pressure of 1 millibar is equivalent to
1000 𝑑𝑦𝑛𝑒𝑠/𝑐𝑚2
1000 cm of Hg
1000 psi
1000 𝑘𝑔 𝑐𝑚2
When a system deviates infinitesimally from equilibrium at every instant of its state, it is undergoing:
isobaric process
quasi-static process
isometric process
cyclic process
What is the force which tends to draw a body toward the center about which it is rotating?
centrifugal force
centrifugal in motion
centrifugal in advance
centripetal force
What is the process that has no heat transfer?
reversible isometric
isothermal
polytropic
adiabatic
Which of the engine is used for fighter bombers?
turbojet
pulse jet
rockets
ramjet
Exhaust gases from an engine posses:
solar energy
kinetic energy
chemical energy
stored energy
At critical point the latent enthalpy of vaporization is
temperature dependent
zero
minimum
maximum
What is the force which tends to draw a body toward the center about which it is rotating?
centrifugal force
centrifugal in motion
centrifugal advance
centripetal force
When a system deviates infinitesimally from equilibrium at every instant of its state, it is undergoing
isobaric process
quasi – static process
isometric process
cyclic process
A pressure of 1 millibar is equivalent to
1000 dynes/cm²
1000 cm of Hg
1000 psi
1000 kg/cm²
Work done per unit charge when charged is moved from one point to another.
equipotential surface
potential at a point
electro static point
potential difference
How many independent properties are required to completely fix the equilibrium state of a pure gaseous compound?
1
2
3
4
Which of the following relations defines enthalpy?
h = u + p/T
h = u +pV
h = u + p/V
h = pV + T
Which of the following is true for water at a reference temperature where enthalpy is zero?
internal energy is negative
entropy is non - zero
specific volume is zero
vapour pressure is zero
On what plane is the Mollier diagram plotted
p - V
p - T
h - s
h - u
The compressibility factor z, is used for predicting the behaviour of non – ideal gasses. How is the compressibility factor defined relative to an ideal gas? (subscript c refers to critical value)
z = P/𝑃c
z = PV/RT
z = T/𝑇c
z = (T/𝑇c) ( 𝑃c/P)
How is the quality x of a liquid – vapour mixture defined?
the fraction of the total volume that is saturated vapor
the fraction of the total volume that is saturated liquid
the fraction of the total mass that is saturated vapor
the fraction of the total mass that is saturated liquid
What is the expression for heat of vaporization?
hg
hf
hg - hf
hf - hg
What is the value of the work done for a closed, reversible, isometric system?
zero
positive
negative
indeterminate
What is the equation for the done by a constant temperature system?
W = mRT ln (𝑉2 - 𝑉2)
W = mRT (𝑇2 − 𝑇1) ln (𝑉2/ 𝑉1)
W = mRT ln (𝑉2/ 𝑉1)
W = RT ln (𝑉2/ 𝑉1)
What is the true about the polytropic exponent n for a perfect gas undergoing an isobaric process?
n > 0
n < 0
n = ∞
n = 0
How does an adiabatic process compare to an isentropic process?
adiabatic: heat transfer = 0, isentropic: heat transfer = 0
adiabatic: heat transfer = 0, isentropic: heat transfer = 0
adiabatic: reversible, isentropic: not reversible
both: heat transfer = 0; isentropic: reversible
During an adiabatic, internally reversible process, what is true about the change in entropy?
it is always zero
it is always less than zero
it is always greater than zero
it is temperature - dependent
For an irreversible process, what is true about the change in entropy of the system and surroundings?
ds = 𝑑𝑞/dt
ds = 0
ds > 0
ds < 0
For which type of process does the equation dQ = Tds hold?
irreversible
reversible
isobaric
isothermal
Which of the following is true for any process?
∆S (surrounding) + ∆ (system) > 0
∆S (surrounding) + ∆ (system) < 0
∆S (surrounding) + ∆ (system) ≤ 0
∆S (surrounding) + ∆ (system) ≥ 0
Which of the following thermodynamic cycle is the most efficient?
Brayton
Rankine
Carnot
Otto
The ideal reversible Carnot cycle involves four basic processes. What type of processes are they?
all isothermal
all adiabatic
all isentropic
two isothermal and two isentropic
What is the temperature difference of the cycle if the entropy difference is ∆S, and the work done is W?
W - ∆S
W / ∆S
∆S / W
∆S - W
Which of the following is not an advantage of a superheated, closed Rankine cycle over an open Rankine cycle?
lower equipment cost
increased efficiency
increased turbine life
increased boiler life
Which of the following statements regarding Rankine cycle is not true?
use of a condensable vapour in the cycle increases the efficiency of the cycle
the temperatures at which energy is transferred to and from the working liquid are less separated than in a Carnot cycle,
super heating increases the efficiency of a Rankine cycle
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 K and 1atm pressure
0 F and zero pressure
32 F and zero pressure
0 ℃ and 1atm pressure
A substance is oxidized when which of the following occurs?
it turns red
it loses electrons
it gives off heat
it absorbs energy
Which of the following is not a unit of pressure?
Pa
𝑘𝑔/ m-s
bars
kg/m2
Which of the following is the definition of Joule?
Newton meter
kg m / s2
unit of power
rate of change of energy
Which of the following is the basis for Bernoulli’s law for fluid flow?
the principle of conservation of mass
the principle of conservation of energy
the continuity equation
Fourier’s law
Equation of state for a single component can be any of the following except:
the ideal gas law
any relationship interrelating 3 or more state functions
relationship mathematically interrelating thermodynamic properties of the material
a mathematical expression defining a path between states
The state of a thermodynamic system is always defined by its:
absolute temperature
process
properties
temperature and pressure
In any non quasi – static thermodynamic process, the overall entropy of an isolated system will
increase and then decrease
decrease and then increase
increase only
decrease only
Entropy is the measure of :
the internal energy of a gas
the heat capacity of a substance
randomness or disorder
the change of enthalpy
Which of the following statements about entropy is false?
entropy of mixture is greater than that of its components under the same condition
an irreversible process increases entropy of the universe
net entropy change in any closed cycle is zero
entropy of a crystal at 0 ℉ 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
Energy changes are represented by all except which one of the following:
m𝐶𝑝dt
- ∫ VdP
Tds - PdV
𝑑𝑄/T
U + pV is a quantity called :
shaft work
entropy
enthalpy
internal energy
In flow process, neglecting KE and PE changes, ∫ vdP represents which item below?
heat transfer
shaft work
enthalpy change
closed system work
Power, may be expressed in units of
ft - lb
Kw - hr
Btu
btu / hr
Equilibrium condition exist in all except which of the following?
in reversible process
in processes where driving forces are infinitesimals
in a steady state flow process
where nothing can occur without an effect on the system’s surrounding
In a closed system (with a moving boundary) which of the following represents work done during an isothermal process?
W = 0
W = P (𝑉2 − 𝑉1)
W = P1v1 ln V2/V1p
W = P2V2 - P1V1 / 1 - n
A substance that exist, or is regarded as existing, as a continuoum characterized by a lo w resistance to flow and the tendency to assume the shape of its container.
fluid
atom
molecule
vapor
A substance that is homogenous in composition and homogenous and invariable in chemical aggregation.
pure substance
simple substance
vapor
water
A substance whose state is defined by variable intensive thermodynamic properties.
pure substance
simple substance
vapor
water
A system in which there is no exchange of matter with the surrounding or mass does not cross its boundaries.
open system
closed system
isolated system
non flow system
A system that is completely impervious to its surrounding or neither mass nor energy cross its boundaries.
open system
closed system
isolated system
non flow system
A system in which there is a flow of mass across its boundaries.
open system
closed system
isolated system
non flow system
The properties that are dependent upon the mass of the system and are total values such as total volume and total internal energy.
intensive properties
extensive properties
specific properties
state properties
The properties that are independent of the mass of the system such as temperature, pressure, density and voltage.
intensive properties
extensive properties
specific properties
state properties
The properties for a unit mass and are intensive by definition such as specific volume.
intensive properties
extensive properties
specific properties
thermodynamic properties
The condition as identified through the properties of the substance, generally defined by particular values of any two independent properties.
state
point
process
flow
