2529474
Pregunta 1
Pregunta
What type of bond exists predominantly in sodium chloride crystal ?
Respuesta
-
ionic bond
-
metallic bond
-
covalent bond
-
polar bond
Pregunta 2
Pregunta
Pure metal A undergoes an isothermal transformation in which its crystal structure changes from face centered cubic FCC to body centered cubic BCC. As a result, the volume of a piece of metal A
Respuesta
-
increased
-
decreased
-
remains the same
-
decreased up to the midpoint of the transformation and then asymptotically reaches its original value
Pregunta 3
Pregunta
Which of the following leads to a reduction in the electrical resistivity of a pure metal ?
Respuesta
-
annealing
-
cold working
-
grain refinement
-
addition of alloying elements
Pregunta 4
Pregunta
The rigidity of polymer can be increased by
Respuesta
-
all of these
-
increase in degree of polymerization
-
increase in the extent of cross linking
-
crystallization
Pregunta 5
Pregunta
Which of the following properties of a metal is insensitive to microstructure ?
Respuesta
-
modulus of elasticity
-
tensile strength
-
ductility
-
hardness
Pregunta 6
Pregunta
The dominant charge carriers in phosphorus - doped silicon crystal at room temperature are
Respuesta
-
electrons
-
electron holes
-
protons
-
silicon ions
Pregunta 7
Pregunta
Metals are conductive because
Respuesta
-
the electrons are loosely bound to the nuclei and therefore mobile
-
they have a characteristic metallic luster
-
they have extra electrons as exhibited by normally positive valence states
-
they are on the left side of the periodic table
Pregunta 8
Pregunta
An X - ray is
Respuesta
-
an electromagnetic radiation
-
a ray of electrons
-
a ray of helium nuclei
-
not known, hence the name " x " ray
Pregunta 9
Pregunta
An electron - volt is
Respuesta
-
a unit of energy equal to the energy possessed by an electron accelerating through a potential of one volt
-
a voltage unit commonly used when measuring the voltage of the electrons
-
the unit of electrical charge of one electron
-
none of the above
Pregunta 10
Pregunta
Group IA are easily ionized because
Respuesta
-
they have a single "s" electrons in the outer orbit
-
they are metals and therefore conductive
-
they react violently in water to liberate hydrogen
-
they have relatively low melting points for metal
Pregunta 11
Pregunta
The rare earth metals all have very similar chemical properties because :
Respuesta
-
successive members of the series are formed by adding 4f electrons which have little effect on the reactivity
-
they are rare, hence little is known about their chemistry
-
they melt at extreme temperatures, hence are nearly inert
-
they are in separate row at the bottom of the periodic table
Pregunta 12
Pregunta
Which of the following group of elements all form crystals of diamond structural lattice ?
Respuesta
-
carbon, silicon, germanium
-
carbon, boron, aluminum
-
carbon, cobalt, nickel
-
lithium, sodium, potassium
Pregunta 13
Pregunta
The stress or load where a crystalline material fails is usually less then the predicted from calculated bond strengths in the crystal lattice because
Respuesta
-
the strength of failure is governed by crystal defects or crystal bond strength
-
the stress at failure is not reproducible experimentally
-
plastic deformation occurs before failure
-
it is, to date, impossible to calculate something as complicated as the stress at failure
Pregunta 14
Pregunta
Which of the following material properties is adversely affected by grain refinement ?
Respuesta
-
creep resistance
-
tensile strength
-
ductility
-
elastic module
Pregunta 15
Pregunta
Which of the following classes of materials exhibit a decreasing electrical conductivity with increasing temperature ?
Respuesta
-
metals
-
pure ionic materials
-
intrinsic semiconductors
-
p - type semiconductors
Pregunta 16
Pregunta
The property that characterizes a material's ability to be drawn into a wire is its
Respuesta
-
ductility
-
tensile strength
-
fatigue endurance limit
-
impact strength
Pregunta 17
Pregunta
Which of the following treatments will result in an increase in the fatigue strength of steel ?
Respuesta
-
short peening
-
annealing
-
cold working
-
surface roughening
Pregunta 18
Pregunta
In p - type semiconductors, conductivity is provided by
Respuesta
-
the motion of holes
-
the motion of electrons
-
the motion of ions
-
the motion of conductivity
Pregunta 19
Pregunta
A photon is
Respuesta
-
a particle of electromagnetic radiation
-
a neutral proton
-
a neutral electron
-
a charge neutron
Pregunta 20
Pregunta
Isotopes of an element are atomic species with
Respuesta
-
the same number of protons and electrons , but different numbers of neutrons
-
the same number electrons , but different numbers of neutrons and protons
-
the same number protons , but different numbers of neutrons and electons
-
the same number of valence electrons , but different numbers of protons, neutrons and non - valence electrons
Pregunta 21
Pregunta
The separation of isotopes of an elements always requires a physical, rather than chemical separation because
Respuesta
-
the differences in isotopes show up as difference in physical properties
-
the atomic mass, a physical characteristic, constitutes the difference between the isotopes
-
the electron configuration and, hence, chemical reactivity are the same
-
all of the above
Pregunta 22
Pregunta
The electronic configuration, 1s² 2s² 2p⁶ 3s² 3p⁵ is that of
Respuesta
-
a halogen
-
an alkali metal
-
an inert gas
-
a transition metal
Pregunta 23
Pregunta
An angstrom unit, commonly used for atomic and sub - atomic distances is equal to
Respuesta
-
10⁻¹⁰ m
-
10¹⁰ m
-
10⁻⁶ m
-
the distance light travels in 10⁻¹⁰ seconds
Pregunta 24
Pregunta
Which of the following statements about free carrier concentration associated with intrinsic semiconductors at room temperature is valid ?
Respuesta
-
it decreases with increasing values of energy gap
-
it increases with increasing values of energy gap
-
in increases with increasing carrier mobility
-
it decreases with increasing carrier mobility
Pregunta 25
Pregunta
At absolute zero temperature, all the valence electrons in an intrinsic semiconductor
Respuesta
-
are in the valence bond
-
are in the forbidden gap
-
are in the conduction bond
-
are free electrons
Pregunta 26
Pregunta
Carrier mobility depends on
Respuesta
-
temperature and the regularity of the crystal structure
-
resistivity
-
conductivity
-
charge per carrier
Pregunta 27
Pregunta
The movement of changers from an area of higher carrier concentration to an area of lower concentration is called
Respuesta
-
diffusion
-
gradient
-
mobility
-
recombination
Pregunta 28
Pregunta
Which term describes a material whose properties depend on the direction of stress
Respuesta
-
anisotropic
-
isotropic
-
endotropic
-
asymmetrical
Pregunta 29
Pregunta
Materials that emit light in the absence of high heat and continue to emit light after the energy source has been removed are called
Respuesta
-
phosphorescent
-
fluorescent
-
semiconductor - laser diodes
-
translucent diodes
Pregunta 30
Pregunta
A gamma ray is composed of
Respuesta
-
high energy electromagnetic radiation
-
high energy protons
-
high energy electrons
-
high energy neutrinos
Pregunta 31
Pregunta
Plank's constant represents
Respuesta
-
the ratio between the magnitude of a quantum of radiated energy and its frequency
-
the quantum or smallest amount of energy that can be emitted by radiation
-
the number of ergs in a kilogram calorie
-
the smallest number of any physical significance
Pregunta 32
Pregunta
The elements exhibit periodically recurring chemical and physical properties because
Respuesta
-
the properties are largely determined by the quantum numbers of the outer electrons, all of which except the first which indicates the orbit, recur in each orbit
-
they are arrange that way in the periodic table
-
the reason is unknown, it is simply observed experimentally
-
probability considerations dictate that properties will recur since there are limited number of possibilities
Pregunta 33
Pregunta
Which element about crystal dislocations is incorrect ?
Respuesta
-
dislocation in a crystalline lattice is located in an unexpected place
-
dislocations affect the tensile strength of a crystal
-
edge, screw and mixed dislocations are possible
-
dislocation is the defect caused by an atomic misalignment in a crystal
Pregunta 34
Pregunta
Ions are formed when
Respuesta
-
all of these
-
electrons are displaced from atoms or molecules by bombardment of high energy particles
-
a salt forms in an acid base neutralization reaction
-
salt crystal forms from the reaction of elemental sodium and chlorine
Pregunta 35
Pregunta
Which of the following statements about two crystalline forms of carbon, graphite and diamond is not correct ?
Respuesta
-
the properties of two crystals are, in fact, more similar than dissimilar
-
the diamond lattice is transparent to visible light, graphite is not
-
diamond is the hardest naturally occurring substance, graphite is soft
-
at high temperature diamond is a semiconductor, graphite is a conductor
Pregunta 36
Pregunta
Avogadro's number represents
Respuesta
-
the number of molecules in one gram mole of any compound
-
the number of molecules in one gram of any compound
-
the number of molecules in one liter of any gas at 1 atm pressure and 0°C
-
the number of valence electrons in a mole of any element
Pregunta 37
Pregunta
Aluminum hydroxide Al(OH)₃ is called an amphoteric hydroxide because
Respuesta
-
it can react as either an acid or a base
-
it has limited solubility in water
-
it contains 3 hydroxyl groups
-
either one, two or three hydroxyl group can ionize in water
Pregunta 38
Pregunta
Which of the following characteristics of the alkaline earth elements is unique
Respuesta
-
they are in group IIA of the periodic table
-
they have two "s" electrons in the outer orbit
-
they exhibit a valence of +2
-
they are found in soil
Pregunta 39
Pregunta
The chemical formula of the salt formed from the neutralization of potassium hydroxide and sulphuric acid is
Respuesta
-
K₂SO₄
-
NaCl
-
P₂SO₄
-
KSO₄
Pregunta 40
Pregunta
The chemical formula of the most common compound formed from beryllium and iodine is
Respuesta
-
BeI₂
-
Be₂I₇
-
BeI
-
Be₇I₂
Pregunta 41
Pregunta
Which of the following statements about the halogens is incorrect ?
Respuesta
-
they will react with water to form very strong bases
-
they are good oxidizing agents
-
they all exhibit a valence of -1
-
they form diatomic molecules
Pregunta 42
Pregunta
The group VIII elements, called the noble or rare gases, have the following properties
Respuesta
-
they do not react with other elements
-
they are rare
-
they are lighter than air
-
they remain gaseous down to just few degrees above absolute zero
Pregunta 43
Pregunta
Many transition metals exhibit more than one valence state in simple chemical reaction because
Respuesta
-
d electrons from one orbital down are not as reactive as the s electrons in the outer orbit
-
s and p electrons in the same orbit have very different reactivities
-
the valence state of metals change of the other elements in the molecule change
-
it is not always possible to predict how even simple reactions will occur
Pregunta 44
Pregunta
For this reaction, the equilibrium conditions are
H₂ + I₂ = 2HI ΔH = -7.9 KJ
Respuesta
-
temperature and concentration
-
pressure, temperature and concentration
-
pressure only
-
temperature only
Pregunta 45
Pregunta
Ammonia is prepared by Haber's process
N₂ + 3H₂ = 2NH₃ ΔH = -5.3 KJ
In order to maximize the yield of ammonia, one can:
Respuesta
-
increase concentrations of hydrogen and nitrogen and decrease the temperature
-
increase concentrations of hydrogen and nitrogen and increase the temperature
-
decrease concentrations of hydrogen and nitrogen and increase the temperature
-
increase the concentrations of all the gases and increase the temperature
Pregunta 46
Pregunta
A close system experiences a reversible process where heat rejection is the only energy transfer. The entropy change
Respuesta
-
must be negative
-
must be zero
-
must be positive
-
is equal to the heat transfer
Pregunta 47
Pregunta
Consider an air - water vapor mixture similar to the atmosphere. If the dry bulb temperature equals the dew point temperature, the relative humidity will be
Respuesta
-
100 %
-
25 %
-
0 %
-
50 %
Pregunta 48
Pregunta
If the temperature of a medium is 0°C, what will be the temperature if it is doubled ?
Respuesta
-
273°C
-
0°C
-
524°R
-
460°R
Pregunta 49
Pregunta
The compression ignition cycle is modeled by which ideal cycle ?
Respuesta
-
diesel cycle
-
otto cycle
-
rankine cycle
-
brayton cycle
Pregunta 50
Pregunta
An ideal gas is contained in a rigid container. There is no work of a rotating shaft associated with the container. Any heat transfer is a function of
Respuesta
-
temperature only
-
pressure only
-
volume only
-
there cannot be any heat transfer
Pregunta 51
Pregunta
In a combustion chamber, fuel is burned to raise the temperature of the medium prior to production of work through an expansion process. The heat generated during the combustion reaction is the
Respuesta
-
heat of reaction
-
specific heat
-
heat of vaporization
-
heat of formation
Pregunta 52
Pregunta
There are many types of work associated with energy transfer across a boundary. One form of work is flow work which is described by all of the following except
Respuesta
-
it is associated with a closed system
-
it is the work which pushes mass in or out of a device
-
it is necessary to maintain a continuous flow
-
it is added to the internal energy to obtain enthalpy in the first law for a control volume
Pregunta 53
Pregunta
An open system First Law should be utilized for all of the following except
Respuesta
-
a piston - cylinder device
-
a nozzle
-
a turbine
-
a compressor
Pregunta 54
Pregunta
An insulated rigid container contains and ideal gas. The container is initially divided in half by a membrane such that one side is a vacuum and the other side contains the ideal gas. The membrane is broken and the gas fills the entire volume. All are true except
Respuesta
-
the temperature is quadrupled
-
the pressure is halved
-
the volume is doubled
-
the process is irreversible
Pregunta 55
Pregunta
An adiabatic process is characterized by which of the following ?
Respuesta
-
the heat transfer is zero
-
the entropy change is zero
-
the work is zero
-
it is reversible
Pregunta 56
Pregunta
A rigid container is heated by the sun. There is no shaft work associated with the container. From the First Law of Thermodynamics, you determine the resulting work to be
Respuesta
-
equal to zero
-
equal to the heat transter
-
equal to the volume times the change in pressure
-
equal to the change in internal energy
Pregunta 57
Pregunta
An inventor claims to have built and engineer which will revolutionize the automotive industry. Which of the following would be the best test to determine if the inventors claim is true ?
Respuesta
-
second law of thermodynamics
-
conservation of mass
-
first law of thermodynamics
-
zeroth law of thermodynamics
Pregunta 58
Pregunta
The isentropic efficiency is used to compare actual device such as turbines, compressors, nozzle and diffusers to ideal ones. Which statement is true
Respuesta
-
the inlet state and exit pressure are the same for both the ideal and actual device
-
only the ideal device is considered adiabatic
-
the ideal device operate irreversibly
-
the efficiency can be greater than one
Pregunta 59
Pregunta
The steam power cycle is modeled by the ideal cycle known as the
Respuesta
-
rankine cycle
-
otto cycle
-
diesel cycle
-
brayton cycle
Pregunta 60
Pregunta
In an ideal refrigeration cycle, liquid leaves the condenser and is expanded in such a manner that the enthalpy of the resulting saturated mixture. This type of expansion is known as
Respuesta
-
throttling process
-
an isothermal process
-
a compression process
-
an isochoric process
Pregunta 61
Pregunta
In the case of regenerative gas turbine engine, which of the following is false ?
Respuesta
-
there is no heat rejected to the atmosphere in a regenerative gas turbine engine
-
the regenerator improves the efficiency of the engine
-
the exit temperature of the generator is higher than the inlet temperature of the compressor
-
if the generator is reversible, the effectiveness can approach 100 %
Pregunta 62
Pregunta
For an ideal turbojet, all of the following statements are true except
Respuesta
-
the work produced by the turbine is greater than the work required by the compressor
-
the process efficiency of the turbine is 100 %
-
the process efficiency of the compressor is 100 %
-
the process efficiency of the nozzle is 100 %
Pregunta 63
Pregunta
Which of the following statements about the carnot efficiency is not true ?
Respuesta
-
no reversible power cycles operating between two thermal reservoir can have an efficiency equal to the carnot efficiency
-
it depends only on the temperatures of the thermal reservoir
-
it can be used to determine if the cycle is possible or impossible
-
absolute temperature scales must be used when performing carnot efficiency calculation
Pregunta 64
Pregunta
Two independent intensive properties are required to fix the state of pure, simple compressible substance. People only attempt to fix the state of the medium using heat and work, which are not properties, which of the following statements about heat and work is not true ?
Respuesta
-
heat and work are point function
-
heat and work are transient phenomena
-
heat and work are forms of energy
-
heat and work are boundary phenomena
Pregunta 65
Pregunta
For steady, incompressible, inviscid flow, with no shaft and heat transfer, Bernoulli's equation can be written P/ρ + ½ v² + gz = constant. This form of equation is valid
Respuesta
-
for rotational flow, but only along streamlines
-
for irrotational flow, but only along streamlines
-
for rotational flow everywhere
-
for rotational flow, but only across streamlines
Pregunta 66
Pregunta
The simplified continuity equation ∇V = 0 is not valid for
Respuesta
-
steady compressible flow
-
steady incompressible flow
-
unsteady incompressible flow
-
steady rotational incompressible flow
Pregunta 67
Pregunta
How many electrons are there in the outermost octate of a chlorine atom ?
Respuesta
-
7
-
1
-
3
-
8
Pregunta 68
Pregunta
Heat transferred at constant volume process to the thermodynamic system of a fixed mass. The thermodynamic system will produce
Respuesta
-
zero work
-
small amount of work
-
negative work
-
positive work
Pregunta 69
Pregunta
Compressibility factor Z is a measure of the deviation of the actual gas behavior from ideal gas. An actual gas behavior may be assumed closed to the ideal gas when compressiblity factor Z approaches
Respuesta
-
1.0
-
0
-
0.5
-
0.75
Pregunta 70
Pregunta
Let's assume that the gas can be heated either at constant pressure or at constant volume process. The amount of heat Qp and Qv are transferred to the gas accordingly. If temperature increment per unit mass ΔT = constant, then
Respuesta
-
Qp is greater than Qv
-
Qp = Qv
-
Qp is less than Qv
-
Qp = Qv - ΔU
Pregunta 71
Pregunta
In manufacturing process 1000 KW of waste heat at temperature 327°C is available for utilization purposes. If the ambient temperature is 27°C, the designed heat engine producing 510 KW of net power will be
Respuesta
-
impossible
-
possible
-
irreversible
-
reversible
Pregunta 72
Pregunta
Which of the following instruments for measuring fluid velocity does not need to be calibrated ?
Respuesta
-
pitot static tube
-
orifice meter
-
venture tube
-
weir
Pregunta 73
Pregunta
Capillarity or the rise or fall of liquid in a thin tube is primarily controlled by which fluid property ?
Respuesta
-
surface tension
-
viscosity
-
density
-
temperature
Pregunta 74
Pregunta
A polytropic process is one in which the functional relationship between pressure and volume is given by PV ᴺ = constant with N value from -∞ to +∞ depending on the particular process. A constant volume process is represented by N equals
Respuesta
-
∞
-
zero
-
2
-
K
Pregunta 75
Pregunta
Cavitation in fluid mechanics refers to
Respuesta
-
a liquid to gaseous phase transition of the fluid due to low pressure
-
the oscillation of a plate due to turbulent fluctuations
-
the condensation of the vapor into liquid due to high pressure
-
the violation of the no slip condition on the wall
Pregunta 76
Pregunta
A large class of devices involve work. Assuming reversible steady state, steady flow process with negligible changes in kinetic and potential energy, the elementary work is
Respuesta
-
- Vdp
-
pdV
-
Vdp + pdV
-
Vdp - pdV
Pregunta 77
Pregunta
The reheat rankine cycle is proposed to decrease
Respuesta
-
moisture content in the low pressure stages of the turbine
-
mass flow rate of cooling water in the condenser
-
back pressure of the turbine
-
volumetric flow rate of the working fluid
Pregunta 78
Pregunta
In compressible fluid mechanics, a shock wave is considered normal shock wave when
Respuesta
-
the angle between the direction of flow and the wave is 90°
-
the shock wave occurs in air
-
the shock wave occurs at oblique angle to the flow
-
the flow remains supersonic on both sides of the shock wave
Pregunta 79
Pregunta
Which of the following statements defines best the capitalized cost ?
Respuesta
-
is the present worth of a specified uniform cash flow for an infinite analysis period
-
it is the initial cost of some equipment
-
it is the salvage value of an equipment
-
it is the amount of money equal to the cost minus benefit for an equipment
Pregunta 80
Pregunta
Which of the following is not taken into account in making an economic decision between two alternative equipment ?
Respuesta
-
reliability
-
operating cost
-
rate of return
-
salvage value
Pregunta 81
Pregunta
A heat sink will dissipate heat energy more rapidly if
Respuesta
-
its surface area is increased
-
its temperature is the same as the temperature of the surrounding air
-
it is covered by a material having a high thermal resistance
-
it is kept away from air current
Pregunta 82
Pregunta
A reference frame which remains fixed while fluid flows through is called
Respuesta
-
Eulerian
-
Lagrangian
-
Stokesian
-
A Navier - Stokes reference frame
Pregunta 83
Pregunta
For steady incompressible fully developed flow in a constant area pipe, friction along the walls of the pipe causes.
Respuesta
-
a reduction in static pressure along the length of the pipe
-
a reduction in mass flow rate along the length of pipe
-
a reduction of velocity along the length of pipe
-
an increase in the darcy friction factor along the length of the pipe
Pregunta 84
Pregunta
Select the answer which correctly ranks fluid meters from lowest to highest pressure loss
Respuesta
-
venturi tube, flow nozzle, thin plate orifice
-
venturi tube,thin plate orifice, flow nozzle
-
thin plate orifice, venturi tube, flow nozzle
-
flow nozzle, thin plate orifice, venturi tube
Pregunta 85
Pregunta
Identify which of the following problems for which the Moody chart would not be of use
Respuesta
-
flow in subsonic diffuser
-
flow of natural gas in long pipe
-
flow of oil in a long channel with square cross section
-
flow of water in a pipe at very high speed where the flow is extremely turbulent
Pregunta 86
Pregunta
Effective interest rate per year is defined as
Respuesta
-
the annual interest rate taking into account the effect of any compounding during the year
-
the nominal interest rate per year
-
the rate of return that can be realized from an investment
-
the interest rate per period times the number of periods per year
Pregunta 87
Pregunta
During inflationary time, which of the following statements best describes the best the loan payments of a fixed amount ?
Respuesta
-
future payments in year zero dollars are not constant in amount
-
future payments are worth more in year zero dollars
-
in actual dollars, the amount of future payments decreases
-
year zero dollars are worth less then future dollars
Pregunta 88
Pregunta
A pump is used to increase the pressure of water entering the boiler of steam power cycle. Which statement is true concerning the pump ?
Respuesta
-
the enthalpy of water leaving the pump is higher than the enthalpy of water entering the pump
-
the pump produces work
-
the pump has no effect on the cycle
-
the enthalpy is constant during the process
Pregunta 89
Pregunta
Which of the following is not a unit of pressure ?
Respuesta
-
kg / m²
-
Pa
-
bars
-
N / m²
Pregunta 90
Pregunta
Which of the following is the definition of Joule ?
Respuesta
-
N - m
-
a unit of power
-
kg - m / s²
-
rate of change of energy
Pregunta 91
Pregunta
Which of the following relations defines enthalpy ?
Respuesta
-
H = U + PV
-
H = U + P / T
-
H = U + P / V
-
H = PV + T
Pregunta 92
Pregunta
How is the quality x of a liquid vapor mixture defined ?
Respuesta
-
the fraction of the total mass that is saturated vapor
-
the fraction of the total volume that is saturated vapor
-
the fraction of total volume that is saturated liquid
-
the fraction of the total mass that is saturated liquid
Pregunta 93
Pregunta
What is the actual shape of the methane CH₄ molecule ?
Respuesta
-
a tetrahedral
-
linear
-
square planar
-
pyramidal
Pregunta 94
Pregunta
What is the oxidation state of the nitrogen in NO₃⁻ ?
Respuesta
-
+ 5
-
- 1
-
+ 3
-
+ 1
Pregunta 95
Pregunta
What is the oxidation number of Cr in the dicromate ion (Cr₂O₇) ²⁻
Respuesta
-
+ 6
-
- 1
-
0
-
7
Pregunta 96
Pregunta
Reactions generally proceed faster at higher temperature because of which of the following ?
Respuesta
-
the activation energy is less
-
the molecules are less energetic
-
the bonds are easier to break
-
the molecules collide more frequently
Pregunta 97
Pregunta
Determine the height of the centroid of the semi - circle with radius r from its diameter
Respuesta
-
4r / 3π
-
2r / 3
-
2πr /3
-
3r / 4π
Pregunta 98
Pregunta
What are valence electrons ?
Respuesta
-
the outer shell electrons
-
electrons with positive charge
-
the electrons of complete quantum shells
-
the K - quantum shell electrons
Pregunta 99
Pregunta
What is the strong bond between hydrogen atoms known as ?
Respuesta
-
covalent bond
-
ionic bond
-
metallic bond
-
ionic and metallic bond
Pregunta 100
Pregunta
What are Van der Waals forces ?
Respuesta
-
weak secondary bonds between atoms
-
primary bonds between atoms
-
forces between electrons and protons
-
forces present only in gases
Pregunta 101
Pregunta
Compare the metallic iron form Fe and the ferric ions Fe²⁺ and Fe³⁺. Which has the smallest atomic radius of the same temperature ?
Respuesta
-
Fe³⁺
-
Fe²⁺
-
Fe
-
they have the same radii
Pregunta 102
Pregunta
Polymers that favor crystallization are least likely to have which of the following
Respuesta
-
an atactic configuration of side group
-
small side group
-
only one repeating unit
-
small chain length
Pregunta 103
Pregunta
In general, what are the effects of cold working a metal ?
Respuesta
-
increase strength, decrease ductility
-
increase strength, increase ductility
-
decrease strength, decrease ductility
-
decrease strength, increase ductility
Pregunta 104
Pregunta
Which of the following is not structural class steel ?
Respuesta
-
tool and die
-
carbon
-
stainless
-
low - alloy
Pregunta 105
Pregunta
Which of the following phases of steel has face - centered cubic structure ?
Respuesta
-
austenite
-
ferrite
-
pearlite
-
martensite
Pregunta 106
Pregunta
The state of a thermodynamic system is always defined by its
Respuesta
-
properties
-
absolute temperature
-
process
-
temperature and pressure
Pregunta 107
Pregunta
Mathematically, a thermodynamic property is which of the following ?
Respuesta
-
a point function
-
a path function
-
an exact differential
-
discontinuous
Pregunta 108
Pregunta
The first law of thermodynamics states that
Respuesta
-
energy can neither be created nor destroyed
-
heat energy cannot be completely transformed into work
-
internal energy is due to molecular motion
-
entropy of the universe is increased by irreversible process
Pregunta 109
Pregunta
In terms of QH and QL, the network of a carnot cycle is
Respuesta
-
W = QH - QL
-
W = QH - QL / QL
-
W = QL / QH - QL
-
W = QL - QH
Pregunta 110
Pregunta
Is any non - quasistatic thermodynamic process, the over - all entropy of an isolated system will
Respuesta
-
increase only
-
decrease only
-
stay the same
-
decrease and then increase
Pregunta 111
Pregunta
Entropy is the measure of
Respuesta
-
randomness or disorder
-
the change in enthalpy of the system
-
the internal energy of the gas
-
the heat capacity of the substance
Pregunta 112
Pregunta
For spontaneously occurring natural process in an isolated system, which expression best express dS ?
Respuesta
-
dS is greater than 0
-
dS equals 0
-
dS is less than zero
-
dS = dQ / T
Pregunta 113
Pregunta
Energy changes are represented by all except
Respuesta
-
dQ rev / T
-
negative integral of VdP
-
mCpdT
-
TdS - PdV
Pregunta 114
Pregunta
Work or energy can be a function of all of the following except
Respuesta
-
force and time
-
force and distance
-
toque and angular acceleration
-
power and time
Pregunta 115
Pregunta
U + PV is a quantity called
Respuesta
-
enthalpy
-
flow energy
-
shaft work
-
entropy
Pregunta 116
Pregunta
In flow process, neglecting KE and PE changes, negative integral of Vdp represents
Respuesta
-
shaft work
-
heat transfer
-
closed system work
-
flow energy
Pregunta 117
Pregunta
Power may be expressed in units of
Respuesta
-
BTU / hr
-
ft - lbs
-
HP - hours
-
KW - hours
Pregunta 118
Pregunta
Equilibrium condition exist in all except which of the following ?
Respuesta
-
in steady state flow process
-
in reversible process
-
in process where driving forces are infinitesimals
-
where nothing can occur without an effect on the system's surroundings
Pregunta 119
Pregunta
Name the process that has no heat transfer
Respuesta
-
isentropic
-
isothermal
-
quasistatic
-
polytropic
Pregunta 120
Pregunta
An ideal gas ( k = 1.4 ) is expanded in a nozzle from Po = 1.5 MPa, To = 150°C, Vo = 0, to P₂ = 0.3 MPa. Assuming reversible adiabatic process the nozzle should be
Respuesta
-
convergent - divergent
-
diverging
-
converging
-
constant cross section
Pregunta 121
Pregunta
Enthalpy of an ideal gas is a function only of
Respuesta
-
temperature
-
entropy
-
pressure
-
internal energy
Pregunta 122
Pregunta
A small plastic bag is filled with moist air at 50% relative humidity, sealed and placed in an environmental chamber whose temperature and pressure may be independently varied. The relative humidity of the bag will lower under which of the following conditions
Respuesta
-
pressure is decreased
-
pressure is increased
-
temperature is decrease
-
temperature is decreased and pressure in increased
Pregunta 123
Pregunta
The rate of heat transfer through a given section of a uniform wall or a given temperature difference is
Respuesta
-
directly proportional to the thermal conductivity and inversely proportional to the thickness of the wall
-
directly proportional to the thermal conductivity and to the thickness of the wall
-
inversely proportional to the thermal conductivity and directly proportional thickness of the wall
-
inversely proportional to the thermal conductivity and to the thickness of the wall
Pregunta 124
Pregunta
Which of the following metals has the highest specific heat capacity at 100°C ?
Respuesta
-
aluminum
-
bismuth
-
copper
-
iron
Pregunta 125
Pregunta
The radical ion (NO₂)⁻ is called
Respuesta
-
nitrite
-
nitrate
-
nitride
-
binitrite
Pregunta 126
Pregunta
a sample of a substance to which chemical formula can be assigned, whose weight is equal to its formula weight is termed as
Respuesta
-
mole
-
molecule
-
gram equivalent weight
-
atom
Pregunta 127
Pregunta
The number of molecules in 22.4 L of a substance in its gaseous state is called
Respuesta
-
Avogadro's number
-
Dulong's number
-
Petit's number
-
Graham's number
Pregunta 128
Pregunta
Which of the following radioactive decay results in an increased Z or number of protons in the nucleus ?
Respuesta
-
negative beta decay ( electron emission )
-
alpha decay ( helium nucleus emission )
-
positive beta decay ( positron emission )
-
gamma emission ( photon energy emission )
Pregunta 129
Pregunta
The relationship between the extension of a spring and the force required to produce the extension is
Respuesta
-
F = kx
-
F = ma
-
F = μN
-
F = mv² / r
Pregunta 130
Pregunta
The deflection of beam is
Respuesta
-
inversely proportional to the modulus of elasticity and the moment of inertia
-
directly proportional to the modulus of elasticity and the moment of inertia
-
inversely proportional to the modulus of elasticity and the length of the beam cube
-
inversely proportional to the weight and length
Pregunta 131
Pregunta
Hard water is water which contains soluble salts of which of the following
Respuesta
-
calcium
-
sodium
-
sulfur
-
chlorine
Pregunta 132
Pregunta
A homogeneous round bar of diameter D, length L and total weight W is hung vertically from one end. If E is the modulus of elasticity, what is the total elongation of the bar ?
Respuesta
-
2WL / πD²E
-
WL / πD²E
-
WL / 2πD²E
-
WL / 2E
Pregunta 133
Pregunta
A thin walled pressurized vessel consist of a right circular cylinder with flat ends. Midway between the ends the stress is greatest in what direction ?
Respuesta
-
circumferential
-
longitudinal
-
radial
-
at an angle of 45° to the longitudinal and circumferential directions
Pregunta 134
Pregunta
The stress concentration factor
Respuesta
-
is the ratio of the maximum stress produced in a cross section to the allowable stress
-
is the ratio of the average stress produced in a cross section to the allowable stress
-
is the ratio of areas involved in the sudden change in cross section
-
cannot be evaluated for brittle material
Pregunta 135
Pregunta
Poisson's ratio is the ratio of
Respuesta
-
unit lateral deformation to the unit of longitudinal deformation
-
unit stress to unit strain
-
elastic limit to proportional limit
-
shear strain to compressive strain
Pregunta 136
Pregunta
The modulus of rigidity of a steel member is
Respuesta
-
defined as the unit shear stress divided by the unit shear deformation
-
a function of the length and depth
-
equal to the modulus of elasticity divided by one Poise
-
defined as the length divided by the moment of inertia
Pregunta 137
Pregunta
A thin homogeneous metallic plate containing a hole is heated sufficiently to cause expansion. If the coefficient of surface expansion is linear, the area of the hole will
Respuesta
-
increase at the same rate as the area of the metal increases
-
decrease at the same rate as the area of the metal increases
-
stay the same
-
increase at twice the rate of the are of the metal increases
Pregunta 138
Pregunta
Hooke's law for an isotropic homogeneous medium experiencing one dimensional stress is
Respuesta
-
stress = E ⋅ strain
-
strain = E ⋅ stress
-
strain energy = E ⋅ internal energy
-
Force ⋅ area = E ⋅ change in length / length
Pregunta 139
Pregunta
The three moment equation may be used to analyze
Respuesta
-
continuous beam
-
beam loaded at the third point
-
a three element composite beam
-
a step tapered column
Pregunta 140
Pregunta
The area of the shear diagram of a beam between any two points on the beam is equal to the
Respuesta
-
change in the moment between the two points
-
change in the shear between the two points
-
total shear beyond the two points
-
average moment between the two points
Pregunta 141
Pregunta
Fixing both ends of a simply supported beam that has only a concentrated load at midspan will increase the allowed load by
Respuesta
-
100 %
-
50 %
-
25 %
-
no change
Pregunta 142
Pregunta
Young's modulus of elasticity for a material can be calculated indirectly form which of the following properties of material ?
Respuesta
-
density and velocity of sound in the material
-
temperature coefficient of expansion and dielectric constant
-
temperature coefficient of expansion and specific heat
-
density and interatomic spacing in the material
Pregunta 143
Pregunta
Modulus of resilience is
Respuesta
-
the measure of a materials ability to store strain energy
-
the same as the modulus of elasticity
-
the reciprocal of the modulus of elasticity
-
a measure of the deflection of a member
Pregunta 144
Pregunta
When a metal is cold worked, all of the following generally occur except
Respuesta
-
grains become equi - axed
-
ductility increases
-
tensile strength increases
-
recrystallization temperature decreases
Pregunta 145
Pregunta
Instrinsic silicon becomes extrinsically conductive, with electrons as majority carriers, when doped with
Respuesta
-
antimony
-
boron
-
germanium
-
aluminum
Pregunta 146
Pregunta
Steel can be strengthened by the following except
Respuesta
-
annealing
-
quenching and tempering
-
work hardening
-
grain refinement
Pregunta 147
Pregunta
If 1080 steel ( 0.8 % wt C ) is annealed by very slow cooling from 1000°C to ambient temperature, its microstructure will consist of almost solely of
Respuesta
-
pearlite
-
austenite
-
bainite
-
cementite
Pregunta 148
Pregunta
Which of the following is not a method of non destructive testing of steel castings and forgings ?
Respuesta
-
chemical analysis
-
radiography
-
magnetic particles
-
ultrasonic
Pregunta 149
Pregunta
Compressive strength of fully cured concrete is most directly related to
Respuesta
-
water - cement ratio
-
sand gravel ratio
-
fineness modulus
-
aggregate gradation
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