Frage 1
Frage
What type of bond exists predominantly in sodium chloride crystal ?
Antworten
-
ionic bond
-
metallic bond
-
covalent bond
-
polar bond
Frage 2
Frage
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
Frage 3
Frage
Which of the following leads to a reduction in the electrical resistivity of a pure metal ?
Frage 4
Frage
The rigidity of polymer can be increased by
Frage 5
Frage
Which of the following properties of a metal is insensitive to microstructure ?
Antworten
-
modulus of elasticity
-
tensile strength
-
ductility
-
hardness
Frage 6
Frage
The dominant charge carriers in phosphorus - doped silicon crystal at room temperature are
Antworten
-
electrons
-
electron holes
-
protons
-
silicon ions
Frage 7
Frage
Metals are conductive because
Antworten
-
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
Frage 8
Frage 9
Frage
An electron - volt is
Antworten
-
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
Frage 10
Frage
Group IA are easily ionized because
Antworten
-
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
Frage 11
Frage
The rare earth metals all have very similar chemical properties because :
Antworten
-
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
Frage 12
Frage
Which of the following group of elements all form crystals of diamond structural lattice ?
Antworten
-
carbon, silicon, germanium
-
carbon, boron, aluminum
-
carbon, cobalt, nickel
-
lithium, sodium, potassium
Frage 13
Frage
The stress or load where a crystalline material fails is usually less then the predicted from calculated bond strengths in the crystal lattice because
Antworten
-
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
Frage 14
Frage
Which of the following material properties is adversely affected by grain refinement ?
Antworten
-
creep resistance
-
tensile strength
-
ductility
-
elastic module
Frage 15
Frage
Which of the following classes of materials exhibit a decreasing electrical conductivity with increasing temperature ?
Antworten
-
metals
-
pure ionic materials
-
intrinsic semiconductors
-
p - type semiconductors
Frage 16
Frage
The property that characterizes a material's ability to be drawn into a wire is its
Antworten
-
ductility
-
tensile strength
-
fatigue endurance limit
-
impact strength
Frage 17
Frage
Which of the following treatments will result in an increase in the fatigue strength of steel ?
Antworten
-
short peening
-
annealing
-
cold working
-
surface roughening
Frage 18
Frage
In p - type semiconductors, conductivity is provided by
Frage 19
Frage 20
Frage
Isotopes of an element are atomic species with
Antworten
-
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
Frage 21
Frage
The separation of isotopes of an elements always requires a physical, rather than chemical separation because
Antworten
-
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
Frage 22
Frage
The electronic configuration, 1s² 2s² 2p⁶ 3s² 3p⁵ is that of
Antworten
-
a halogen
-
an alkali metal
-
an inert gas
-
a transition metal
Frage 23
Frage
An angstrom unit, commonly used for atomic and sub - atomic distances is equal to
Frage 24
Frage
Which of the following statements about free carrier concentration associated with intrinsic semiconductors at room temperature is valid ?
Antworten
-
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
Frage 25
Frage
At absolute zero temperature, all the valence electrons in an intrinsic semiconductor
Frage 26
Frage
Carrier mobility depends on
Frage 27
Frage
The movement of changers from an area of higher carrier concentration to an area of lower concentration is called
Antworten
-
diffusion
-
gradient
-
mobility
-
recombination
Frage 28
Frage
Which term describes a material whose properties depend on the direction of stress
Antworten
-
anisotropic
-
isotropic
-
endotropic
-
asymmetrical
Frage 29
Frage
Materials that emit light in the absence of high heat and continue to emit light after the energy source has been removed are called
Frage 30
Frage
A gamma ray is composed of
Frage 31
Frage
Plank's constant represents
Antworten
-
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
Frage 32
Frage
The elements exhibit periodically recurring chemical and physical properties because
Antworten
-
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
Frage 33
Frage
Which element about crystal dislocations is incorrect ?
Antworten
-
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
Frage 34
Frage
Ions are formed when
Antworten
-
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
Frage 35
Frage
Which of the following statements about two crystalline forms of carbon, graphite and diamond is not correct ?
Antworten
-
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
Frage 36
Frage
Avogadro's number represents
Antworten
-
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
Frage 37
Frage
Aluminum hydroxide Al(OH)₃ is called an amphoteric hydroxide because
Antworten
-
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
Frage 38
Frage
Which of the following characteristics of the alkaline earth elements is unique
Antworten
-
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
Frage 39
Frage
The chemical formula of the salt formed from the neutralization of potassium hydroxide and sulphuric acid is
Frage 40
Frage
The chemical formula of the most common compound formed from beryllium and iodine is
Frage 41
Frage
Which of the following statements about the halogens is incorrect ?
Antworten
-
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
Frage 42
Frage
The group VIII elements, called the noble or rare gases, have the following properties
Antworten
-
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
Frage 43
Frage
Many transition metals exhibit more than one valence state in simple chemical reaction because
Antworten
-
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
Frage 44
Frage
For this reaction, the equilibrium conditions are
H₂ + I₂ = 2HI ΔH = -7.9 KJ
Frage 45
Frage
Ammonia is prepared by Haber's process
N₂ + 3H₂ = 2NH₃ ΔH = -5.3 KJ
In order to maximize the yield of ammonia, one can:
Antworten
-
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
Frage 46
Frage
A close system experiences a reversible process where heat rejection is the only energy transfer. The entropy change
Frage 47
Frage
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
Frage 48
Frage
If the temperature of a medium is 0°C, what will be the temperature if it is doubled ?
Frage 49
Frage
The compression ignition cycle is modeled by which ideal cycle ?
Antworten
-
diesel cycle
-
otto cycle
-
rankine cycle
-
brayton cycle
Frage 50
Frage
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
Frage 51
Frage
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
Antworten
-
heat of reaction
-
specific heat
-
heat of vaporization
-
heat of formation
Frage 52
Frage
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
Antworten
-
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
Frage 53
Frage
An open system First Law should be utilized for all of the following except
Frage 54
Frage
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
Frage 55
Frage
An adiabatic process is characterized by which of the following ?
Frage 56
Frage
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
Antworten
-
equal to zero
-
equal to the heat transter
-
equal to the volume times the change in pressure
-
equal to the change in internal energy
Frage 57
Frage
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 ?
Antworten
-
second law of thermodynamics
-
conservation of mass
-
first law of thermodynamics
-
zeroth law of thermodynamics
Frage 58
Frage
The isentropic efficiency is used to compare actual device such as turbines, compressors, nozzle and diffusers to ideal ones. Which statement is true
Antworten
-
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
Frage 59
Frage
The steam power cycle is modeled by the ideal cycle known as the
Antworten
-
rankine cycle
-
otto cycle
-
diesel cycle
-
brayton cycle
Frage 60
Frage
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
Antworten
-
throttling process
-
an isothermal process
-
a compression process
-
an isochoric process
Frage 61
Frage
In the case of regenerative gas turbine engine, which of the following is false ?
Antworten
-
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 %
Frage 62
Frage
For an ideal turbojet, all of the following statements are true except
Antworten
-
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 %
Frage 63
Frage
Which of the following statements about the carnot efficiency is not true ?
Antworten
-
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
Frage 64
Frage
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 ?
Antworten
-
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
Frage 65
Frage
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
Antworten
-
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
Frage 66
Frage
The simplified continuity equation ∇V = 0 is not valid for
Antworten
-
steady compressible flow
-
steady incompressible flow
-
unsteady incompressible flow
-
steady rotational incompressible flow
Frage 67
Frage
How many electrons are there in the outermost octate of a chlorine atom ?
Frage 68
Frage
Heat transferred at constant volume process to the thermodynamic system of a fixed mass. The thermodynamic system will produce
Antworten
-
zero work
-
small amount of work
-
negative work
-
positive work
Frage 69
Frage
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
Frage 70
Frage
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
Antworten
-
Qp is greater than Qv
-
Qp = Qv
-
Qp is less than Qv
-
Qp = Qv - ΔU
Frage 71
Frage
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
Antworten
-
impossible
-
possible
-
irreversible
-
reversible
Frage 72
Frage
Which of the following instruments for measuring fluid velocity does not need to be calibrated ?
Antworten
-
pitot static tube
-
orifice meter
-
venture tube
-
weir
Frage 73
Frage
Capillarity or the rise or fall of liquid in a thin tube is primarily controlled by which fluid property ?
Antworten
-
surface tension
-
viscosity
-
density
-
temperature
Frage 74
Frage
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
Frage 75
Frage
Cavitation in fluid mechanics refers to
Antworten
-
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
Frage 76
Frage
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
Antworten
-
- Vdp
-
pdV
-
Vdp + pdV
-
Vdp - pdV
Frage 77
Frage
The reheat rankine cycle is proposed to decrease
Antworten
-
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
Frage 78
Frage
In compressible fluid mechanics, a shock wave is considered normal shock wave when
Antworten
-
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
Frage 79
Frage
Which of the following statements defines best the capitalized cost ?
Antworten
-
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
Frage 80
Frage
Which of the following is not taken into account in making an economic decision between two alternative equipment ?
Antworten
-
reliability
-
operating cost
-
rate of return
-
salvage value
Frage 81
Frage
A heat sink will dissipate heat energy more rapidly if
Antworten
-
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
Frage 82
Frage
A reference frame which remains fixed while fluid flows through is called
Frage 83
Frage
For steady incompressible fully developed flow in a constant area pipe, friction along the walls of the pipe causes.
Antworten
-
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
Frage 84
Frage
Select the answer which correctly ranks fluid meters from lowest to highest pressure loss
Antworten
-
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
Frage 85
Frage
Identify which of the following problems for which the Moody chart would not be of use
Antworten
-
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
Frage 86
Frage
Effective interest rate per year is defined as
Antworten
-
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
Frage 87
Frage
During inflationary time, which of the following statements best describes the best the loan payments of a fixed amount ?
Antworten
-
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
Frage 88
Frage
A pump is used to increase the pressure of water entering the boiler of steam power cycle. Which statement is true concerning the pump ?
Antworten
-
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
Frage 89
Frage
Which of the following is not a unit of pressure ?
Frage 90
Frage
Which of the following is the definition of Joule ?
Antworten
-
N - m
-
a unit of power
-
kg - m / s²
-
rate of change of energy
Frage 91
Frage
Which of the following relations defines enthalpy ?
Antworten
-
H = U + PV
-
H = U + P / T
-
H = U + P / V
-
H = PV + T
Frage 92
Frage
How is the quality x of a liquid vapor mixture defined ?
Antworten
-
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
Frage 93
Frage
What is the actual shape of the methane CH₄ molecule ?
Antworten
-
a tetrahedral
-
linear
-
square planar
-
pyramidal
Frage 94
Frage
What is the oxidation state of the nitrogen in NO₃⁻ ?
Frage 95
Frage
What is the oxidation number of Cr in the dicromate ion (Cr₂O₇) ²⁻
Frage 96
Frage
Reactions generally proceed faster at higher temperature because of which of the following ?
Antworten
-
the activation energy is less
-
the molecules are less energetic
-
the bonds are easier to break
-
the molecules collide more frequently
Frage 97
Frage
Determine the height of the centroid of the semi - circle with radius r from its diameter
Antworten
-
4r / 3π
-
2r / 3
-
2πr /3
-
3r / 4π
Frage 98
Frage
What are valence electrons ?
Antworten
-
the outer shell electrons
-
electrons with positive charge
-
the electrons of complete quantum shells
-
the K - quantum shell electrons
Frage 99
Frage
What is the strong bond between hydrogen atoms known as ?
Antworten
-
covalent bond
-
ionic bond
-
metallic bond
-
ionic and metallic bond
Frage 100
Frage
What are Van der Waals forces ?
Antworten
-
weak secondary bonds between atoms
-
primary bonds between atoms
-
forces between electrons and protons
-
forces present only in gases
Frage 101
Frage
Compare the metallic iron form Fe and the ferric ions Fe²⁺ and Fe³⁺. Which has the smallest atomic radius of the same temperature ?
Antworten
-
Fe³⁺
-
Fe²⁺
-
Fe
-
they have the same radii
Frage 102
Frage
Polymers that favor crystallization are least likely to have which of the following
Frage 103
Frage
In general, what are the effects of cold working a metal ?
Antworten
-
increase strength, decrease ductility
-
increase strength, increase ductility
-
decrease strength, decrease ductility
-
decrease strength, increase ductility
Frage 104
Frage
Which of the following is not structural class steel ?
Antworten
-
tool and die
-
carbon
-
stainless
-
low - alloy
Frage 105
Frage
Which of the following phases of steel has face - centered cubic structure ?
Antworten
-
austenite
-
ferrite
-
pearlite
-
martensite
Frage 106
Frage
The state of a thermodynamic system is always defined by its
Antworten
-
properties
-
absolute temperature
-
process
-
temperature and pressure
Frage 107
Frage
Mathematically, a thermodynamic property is which of the following ?
Antworten
-
a point function
-
a path function
-
an exact differential
-
discontinuous
Frage 108
Frage
The first law of thermodynamics states that
Antworten
-
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
Frage 109
Frage
In terms of QH and QL, the network of a carnot cycle is
Antworten
-
W = QH - QL
-
W = QH - QL / QL
-
W = QL / QH - QL
-
W = QL - QH
Frage 110
Frage
Is any non - quasistatic thermodynamic process, the over - all entropy of an isolated system will
Frage 111
Frage
Entropy is the measure of
Antworten
-
randomness or disorder
-
the change in enthalpy of the system
-
the internal energy of the gas
-
the heat capacity of the substance
Frage 112
Frage
For spontaneously occurring natural process in an isolated system, which expression best express dS ?
Antworten
-
dS is greater than 0
-
dS equals 0
-
dS is less than zero
-
dS = dQ / T
Frage 113
Frage
Energy changes are represented by all except
Antworten
-
dQ rev / T
-
negative integral of VdP
-
mCpdT
-
TdS - PdV
Frage 114
Frage
Work or energy can be a function of all of the following except
Frage 115
Frage
U + PV is a quantity called
Antworten
-
enthalpy
-
flow energy
-
shaft work
-
entropy
Frage 116
Frage
In flow process, neglecting KE and PE changes, negative integral of Vdp represents
Antworten
-
shaft work
-
heat transfer
-
closed system work
-
flow energy
Frage 117
Frage
Power may be expressed in units of
Antworten
-
BTU / hr
-
ft - lbs
-
HP - hours
-
KW - hours
Frage 118
Frage
Equilibrium condition exist in all except which of the following ?
Antworten
-
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
Frage 119
Frage
Name the process that has no heat transfer
Antworten
-
isentropic
-
isothermal
-
quasistatic
-
polytropic
Frage 120
Frage
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
Antworten
-
convergent - divergent
-
diverging
-
converging
-
constant cross section
Frage 121
Frage
Enthalpy of an ideal gas is a function only of
Antworten
-
temperature
-
entropy
-
pressure
-
internal energy
Frage 122
Frage
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
Frage 123
Frage
The rate of heat transfer through a given section of a uniform wall or a given temperature difference is
Antworten
-
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
Frage 124
Frage
Which of the following metals has the highest specific heat capacity at 100°C ?
Antworten
-
aluminum
-
bismuth
-
copper
-
iron
Frage 125
Frage
The radical ion (NO₂)⁻ is called
Antworten
-
nitrite
-
nitrate
-
nitride
-
binitrite
Frage 126
Frage
a sample of a substance to which chemical formula can be assigned, whose weight is equal to its formula weight is termed as
Antworten
-
mole
-
molecule
-
gram equivalent weight
-
atom
Frage 127
Frage
The number of molecules in 22.4 L of a substance in its gaseous state is called
Antworten
-
Avogadro's number
-
Dulong's number
-
Petit's number
-
Graham's number
Frage 128
Frage
Which of the following radioactive decay results in an increased Z or number of protons in the nucleus ?
Antworten
-
negative beta decay ( electron emission )
-
alpha decay ( helium nucleus emission )
-
positive beta decay ( positron emission )
-
gamma emission ( photon energy emission )
Frage 129
Frage
The relationship between the extension of a spring and the force required to produce the extension is
Antworten
-
F = kx
-
F = ma
-
F = μN
-
F = mv² / r
Frage 130
Frage
The deflection of beam is
Antworten
-
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
Frage 131
Frage
Hard water is water which contains soluble salts of which of the following
Antworten
-
calcium
-
sodium
-
sulfur
-
chlorine
Frage 132
Frage
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 ?
Antworten
-
2WL / πD²E
-
WL / πD²E
-
WL / 2πD²E
-
WL / 2E
Frage 133
Frage
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 ?
Frage 134
Frage
The stress concentration factor
Antworten
-
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
Frage 135
Frage
Poisson's ratio is the ratio of
Antworten
-
unit lateral deformation to the unit of longitudinal deformation
-
unit stress to unit strain
-
elastic limit to proportional limit
-
shear strain to compressive strain
Frage 136
Frage
The modulus of rigidity of a steel member is
Antworten
-
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
Frage 137
Frage
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
Antworten
-
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
Frage 138
Frage
Hooke's law for an isotropic homogeneous medium experiencing one dimensional stress is
Frage 139
Frage
The three moment equation may be used to analyze
Frage 140
Frage
The area of the shear diagram of a beam between any two points on the beam is equal to the
Antworten
-
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
Frage 141
Frage
Fixing both ends of a simply supported beam that has only a concentrated load at midspan will increase the allowed load by
Antworten
-
100 %
-
50 %
-
25 %
-
no change
Frage 142
Frage
Young's modulus of elasticity for a material can be calculated indirectly form which of the following properties of material ?
Antworten
-
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
Frage 143
Frage
Modulus of resilience is
Antworten
-
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
Frage 144
Frage
When a metal is cold worked, all of the following generally occur except
Antworten
-
grains become equi - axed
-
ductility increases
-
tensile strength increases
-
recrystallization temperature decreases
Frage 145
Frage
Instrinsic silicon becomes extrinsically conductive, with electrons as majority carriers, when doped with
Antworten
-
antimony
-
boron
-
germanium
-
aluminum
Frage 146
Frage
Steel can be strengthened by the following except
Antworten
-
annealing
-
quenching and tempering
-
work hardening
-
grain refinement
Frage 147
Frage
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
Antworten
-
pearlite
-
austenite
-
bainite
-
cementite
Frage 148
Frage
Which of the following is not a method of non destructive testing of steel castings and forgings ?
Antworten
-
chemical analysis
-
radiography
-
magnetic particles
-
ultrasonic
Frage 149
Frage
Compressive strength of fully cured concrete is most directly related to
Antworten
-
water - cement ratio
-
sand gravel ratio
-
fineness modulus
-
aggregate gradation