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GENERAL ENGINEERING II

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Quiz sobre GENERAL ENGINEERING II, criado por shuree em 18-04-2015.
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Quiz por shuree, atualizado more than 1 year ago
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Criado por shuree mais de 9 anos atrás
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Resumo de Recurso

Questão 1

Questão
What type of bond exists predominantly in sodium chloride crystal ?
Responda
  • ionic bond
  • metallic bond
  • covalent bond
  • polar bond

Questão 2

Questão
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
Responda
  • increased
  • decreased
  • remains the same
  • decreased up to the midpoint of the transformation and then asymptotically reaches its original value

Questão 3

Questão
Which of the following leads to a reduction in the electrical resistivity of a pure metal ?
Responda
  • annealing
  • cold working
  • grain refinement
  • addition of alloying elements

Questão 4

Questão
The rigidity of polymer can be increased by
Responda
  • all of these
  • increase in degree of polymerization
  • increase in the extent of cross linking
  • crystallization

Questão 5

Questão
Which of the following properties of a metal is insensitive to microstructure ?
Responda
  • modulus of elasticity
  • tensile strength
  • ductility
  • hardness

Questão 6

Questão
The dominant charge carriers in phosphorus - doped silicon crystal at room temperature are
Responda
  • electrons
  • electron holes
  • protons
  • silicon ions

Questão 7

Questão
Metals are conductive because
Responda
  • 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

Questão 8

Questão
An X - ray is
Responda
  • an electromagnetic radiation
  • a ray of electrons
  • a ray of helium nuclei
  • not known, hence the name " x " ray

Questão 9

Questão
An electron - volt is
Responda
  • 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

Questão 10

Questão
Group IA are easily ionized because
Responda
  • 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

Questão 11

Questão
The rare earth metals all have very similar chemical properties because :
Responda
  • 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

Questão 12

Questão
Which of the following group of elements all form crystals of diamond structural lattice ?
Responda
  • carbon, silicon, germanium
  • carbon, boron, aluminum
  • carbon, cobalt, nickel
  • lithium, sodium, potassium

Questão 13

Questão
The stress or load where a crystalline material fails is usually less then the predicted from calculated bond strengths in the crystal lattice because
Responda
  • 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

Questão 14

Questão
Which of the following material properties is adversely affected by grain refinement ?
Responda
  • creep resistance
  • tensile strength
  • ductility
  • elastic module

Questão 15

Questão
Which of the following classes of materials exhibit a decreasing electrical conductivity with increasing temperature ?
Responda
  • metals
  • pure ionic materials
  • intrinsic semiconductors
  • p - type semiconductors

Questão 16

Questão
The property that characterizes a material's ability to be drawn into a wire is its
Responda
  • ductility
  • tensile strength
  • fatigue endurance limit
  • impact strength

Questão 17

Questão
Which of the following treatments will result in an increase in the fatigue strength of steel ?
Responda
  • short peening
  • annealing
  • cold working
  • surface roughening

Questão 18

Questão
In p - type semiconductors, conductivity is provided by
Responda
  • the motion of holes
  • the motion of electrons
  • the motion of ions
  • the motion of conductivity

Questão 19

Questão
A photon is
Responda
  • a particle of electromagnetic radiation
  • a neutral proton
  • a neutral electron
  • a charge neutron

Questão 20

Questão
Isotopes of an element are atomic species with
Responda
  • 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

Questão 21

Questão
The separation of isotopes of an elements always requires a physical, rather than chemical separation because
Responda
  • 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

Questão 22

Questão
The electronic configuration, 1s² 2s² 2p⁶ 3s² 3p⁵ is that of
Responda
  • a halogen
  • an alkali metal
  • an inert gas
  • a transition metal

Questão 23

Questão
An angstrom unit, commonly used for atomic and sub - atomic distances is equal to
Responda
  • 10⁻¹⁰ m
  • 10¹⁰ m
  • 10⁻⁶ m
  • the distance light travels in 10⁻¹⁰ seconds

Questão 24

Questão
Which of the following statements about free carrier concentration associated with intrinsic semiconductors at room temperature is valid ?
Responda
  • 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

Questão 25

Questão
At absolute zero temperature, all the valence electrons in an intrinsic semiconductor
Responda
  • are in the valence bond
  • are in the forbidden gap
  • are in the conduction bond
  • are free electrons

Questão 26

Questão
Carrier mobility depends on
Responda
  • temperature and the regularity of the crystal structure
  • resistivity
  • conductivity
  • charge per carrier

Questão 27

Questão
The movement of changers from an area of higher carrier concentration to an area of lower concentration is called
Responda
  • diffusion
  • gradient
  • mobility
  • recombination

Questão 28

Questão
Which term describes a material whose properties depend on the direction of stress
Responda
  • anisotropic
  • isotropic
  • endotropic
  • asymmetrical

Questão 29

Questão
Materials that emit light in the absence of high heat and continue to emit light after the energy source has been removed are called
Responda
  • phosphorescent
  • fluorescent
  • semiconductor - laser diodes
  • translucent diodes

Questão 30

Questão
A gamma ray is composed of
Responda
  • high energy electromagnetic radiation
  • high energy protons
  • high energy electrons
  • high energy neutrinos

Questão 31

Questão
Plank's constant represents
Responda
  • 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

Questão 32

Questão
The elements exhibit periodically recurring chemical and physical properties because
Responda
  • 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

Questão 33

Questão
Which element about crystal dislocations is incorrect ?
Responda
  • 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

Questão 34

Questão
Ions are formed when
Responda
  • 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

Questão 35

Questão
Which of the following statements about two crystalline forms of carbon, graphite and diamond is not correct ?
Responda
  • 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

Questão 36

Questão
Avogadro's number represents
Responda
  • 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

Questão 37

Questão
Aluminum hydroxide Al(OH)₃ is called an amphoteric hydroxide because
Responda
  • 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

Questão 38

Questão
Which of the following characteristics of the alkaline earth elements is unique
Responda
  • 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

Questão 39

Questão
The chemical formula of the salt formed from the neutralization of potassium hydroxide and sulphuric acid is
Responda
  • K₂SO₄
  • NaCl
  • P₂SO₄
  • KSO₄

Questão 40

Questão
The chemical formula of the most common compound formed from beryllium and iodine is
Responda
  • BeI₂
  • Be₂I₇
  • BeI
  • Be₇I₂

Questão 41

Questão
Which of the following statements about the halogens is incorrect ?
Responda
  • 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

Questão 42

Questão
The group VIII elements, called the noble or rare gases, have the following properties
Responda
  • 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

Questão 43

Questão
Many transition metals exhibit more than one valence state in simple chemical reaction because
Responda
  • 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

Questão 44

Questão
For this reaction, the equilibrium conditions are H₂ + I₂ = 2HI ΔH = -7.9 KJ
Responda
  • temperature and concentration
  • pressure, temperature and concentration
  • pressure only
  • temperature only

Questão 45

Questão
Ammonia is prepared by Haber's process N₂ + 3H₂ = 2NH₃ ΔH = -5.3 KJ In order to maximize the yield of ammonia, one can:
Responda
  • 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

Questão 46

Questão
A close system experiences a reversible process where heat rejection is the only energy transfer. The entropy change
Responda
  • must be negative
  • must be zero
  • must be positive
  • is equal to the heat transfer

Questão 47

Questão
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
Responda
  • 100 %
  • 25 %
  • 0 %
  • 50 %

Questão 48

Questão
If the temperature of a medium is 0°C, what will be the temperature if it is doubled ?
Responda
  • 273°C
  • 0°C
  • 524°R
  • 460°R

Questão 49

Questão
The compression ignition cycle is modeled by which ideal cycle ?
Responda
  • diesel cycle
  • otto cycle
  • rankine cycle
  • brayton cycle

Questão 50

Questão
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
Responda
  • temperature only
  • pressure only
  • volume only
  • there cannot be any heat transfer

Questão 51

Questão
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
Responda
  • heat of reaction
  • specific heat
  • heat of vaporization
  • heat of formation

Questão 52

Questão
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
Responda
  • 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

Questão 53

Questão
An open system First Law should be utilized for all of the following except
Responda
  • a piston - cylinder device
  • a nozzle
  • a turbine
  • a compressor

Questão 54

Questão
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
Responda
  • the temperature is quadrupled
  • the pressure is halved
  • the volume is doubled
  • the process is irreversible

Questão 55

Questão
An adiabatic process is characterized by which of the following ?
Responda
  • the heat transfer is zero
  • the entropy change is zero
  • the work is zero
  • it is reversible

Questão 56

Questão
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
Responda
  • equal to zero
  • equal to the heat transter
  • equal to the volume times the change in pressure
  • equal to the change in internal energy

Questão 57

Questão
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 ?
Responda
  • second law of thermodynamics
  • conservation of mass
  • first law of thermodynamics
  • zeroth law of thermodynamics

Questão 58

Questão
The isentropic efficiency is used to compare actual device such as turbines, compressors, nozzle and diffusers to ideal ones. Which statement is true
Responda
  • 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

Questão 59

Questão
The steam power cycle is modeled by the ideal cycle known as the
Responda
  • rankine cycle
  • otto cycle
  • diesel cycle
  • brayton cycle

Questão 60

Questão
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
Responda
  • throttling process
  • an isothermal process
  • a compression process
  • an isochoric process

Questão 61

Questão
In the case of regenerative gas turbine engine, which of the following is false ?
Responda
  • 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 %

Questão 62

Questão
For an ideal turbojet, all of the following statements are true except
Responda
  • 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 %

Questão 63

Questão
Which of the following statements about the carnot efficiency is not true ?
Responda
  • 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

Questão 64

Questão
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 ?
Responda
  • 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

Questão 65

Questão
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
Responda
  • 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

Questão 66

Questão
The simplified continuity equation ∇V = 0 is not valid for
Responda
  • steady compressible flow
  • steady incompressible flow
  • unsteady incompressible flow
  • steady rotational incompressible flow

Questão 67

Questão
How many electrons are there in the outermost octate of a chlorine atom ?
Responda
  • 7
  • 1
  • 3
  • 8

Questão 68

Questão
Heat transferred at constant volume process to the thermodynamic system of a fixed mass. The thermodynamic system will produce
Responda
  • zero work
  • small amount of work
  • negative work
  • positive work

Questão 69

Questão
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
Responda
  • 1.0
  • 0
  • 0.5
  • 0.75

Questão 70

Questão
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
Responda
  • Qp is greater than Qv
  • Qp = Qv
  • Qp is less than Qv
  • Qp = Qv - ΔU

Questão 71

Questão
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
Responda
  • impossible
  • possible
  • irreversible
  • reversible

Questão 72

Questão
Which of the following instruments for measuring fluid velocity does not need to be calibrated ?
Responda
  • pitot static tube
  • orifice meter
  • venture tube
  • weir

Questão 73

Questão
Capillarity or the rise or fall of liquid in a thin tube is primarily controlled by which fluid property ?
Responda
  • surface tension
  • viscosity
  • density
  • temperature

Questão 74

Questão
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
Responda
  • ∞
  • zero
  • 2
  • K

Questão 75

Questão
Cavitation in fluid mechanics refers to
Responda
  • 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

Questão 76

Questão
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
Responda
  • - Vdp
  • pdV
  • Vdp + pdV
  • Vdp - pdV

Questão 77

Questão
The reheat rankine cycle is proposed to decrease
Responda
  • 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

Questão 78

Questão
In compressible fluid mechanics, a shock wave is considered normal shock wave when
Responda
  • 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

Questão 79

Questão
Which of the following statements defines best the capitalized cost ?
Responda
  • 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

Questão 80

Questão
Which of the following is not taken into account in making an economic decision between two alternative equipment ?
Responda
  • reliability
  • operating cost
  • rate of return
  • salvage value

Questão 81

Questão
A heat sink will dissipate heat energy more rapidly if
Responda
  • 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

Questão 82

Questão
A reference frame which remains fixed while fluid flows through is called
Responda
  • Eulerian
  • Lagrangian
  • Stokesian
  • A Navier - Stokes reference frame

Questão 83

Questão
For steady incompressible fully developed flow in a constant area pipe, friction along the walls of the pipe causes.
Responda
  • 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

Questão 84

Questão
Select the answer which correctly ranks fluid meters from lowest to highest pressure loss
Responda
  • 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

Questão 85

Questão
Identify which of the following problems for which the Moody chart would not be of use
Responda
  • 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

Questão 86

Questão
Effective interest rate per year is defined as
Responda
  • 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

Questão 87

Questão
During inflationary time, which of the following statements best describes the best the loan payments of a fixed amount ?
Responda
  • 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

Questão 88

Questão
A pump is used to increase the pressure of water entering the boiler of steam power cycle. Which statement is true concerning the pump ?
Responda
  • 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

Questão 89

Questão
Which of the following is not a unit of pressure ?
Responda
  • kg / m²
  • Pa
  • bars
  • N / m²

Questão 90

Questão
Which of the following is the definition of Joule ?
Responda
  • N - m
  • a unit of power
  • kg - m / s²
  • rate of change of energy

Questão 91

Questão
Which of the following relations defines enthalpy ?
Responda
  • H = U + PV
  • H = U + P / T
  • H = U + P / V
  • H = PV + T

Questão 92

Questão
How is the quality x of a liquid vapor mixture defined ?
Responda
  • 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

Questão 93

Questão
What is the actual shape of the methane CH₄ molecule ?
Responda
  • a tetrahedral
  • linear
  • square planar
  • pyramidal

Questão 94

Questão
What is the oxidation state of the nitrogen in NO₃⁻ ?
Responda
  • + 5
  • - 1
  • + 3
  • + 1

Questão 95

Questão
What is the oxidation number of Cr in the dicromate ion (Cr₂O₇) ²⁻
Responda
  • + 6
  • - 1
  • 0
  • 7

Questão 96

Questão
Reactions generally proceed faster at higher temperature because of which of the following ?
Responda
  • the activation energy is less
  • the molecules are less energetic
  • the bonds are easier to break
  • the molecules collide more frequently

Questão 97

Questão
Determine the height of the centroid of the semi - circle with radius r from its diameter
Responda
  • 4r / 3π
  • 2r / 3
  • 2πr /3
  • 3r / 4π

Questão 98

Questão
What are valence electrons ?
Responda
  • the outer shell electrons
  • electrons with positive charge
  • the electrons of complete quantum shells
  • the K - quantum shell electrons

Questão 99

Questão
What is the strong bond between hydrogen atoms known as ?
Responda
  • covalent bond
  • ionic bond
  • metallic bond
  • ionic and metallic bond

Questão 100

Questão
What are Van der Waals forces ?
Responda
  • weak secondary bonds between atoms
  • primary bonds between atoms
  • forces between electrons and protons
  • forces present only in gases

Questão 101

Questão
Compare the metallic iron form Fe and the ferric ions Fe²⁺ and Fe³⁺. Which has the smallest atomic radius of the same temperature ?
Responda
  • Fe³⁺
  • Fe²⁺
  • Fe
  • they have the same radii

Questão 102

Questão
Polymers that favor crystallization are least likely to have which of the following
Responda
  • an atactic configuration of side group
  • small side group
  • only one repeating unit
  • small chain length

Questão 103

Questão
In general, what are the effects of cold working a metal ?
Responda
  • increase strength, decrease ductility
  • increase strength, increase ductility
  • decrease strength, decrease ductility
  • decrease strength, increase ductility

Questão 104

Questão
Which of the following is not structural class steel ?
Responda
  • tool and die
  • carbon
  • stainless
  • low - alloy

Questão 105

Questão
Which of the following phases of steel has face - centered cubic structure ?
Responda
  • austenite
  • ferrite
  • pearlite
  • martensite

Questão 106

Questão
The state of a thermodynamic system is always defined by its
Responda
  • properties
  • absolute temperature
  • process
  • temperature and pressure

Questão 107

Questão
Mathematically, a thermodynamic property is which of the following ?
Responda
  • a point function
  • a path function
  • an exact differential
  • discontinuous

Questão 108

Questão
The first law of thermodynamics states that
Responda
  • 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

Questão 109

Questão
In terms of QH and QL, the network of a carnot cycle is
Responda
  • W = QH - QL
  • W = QH - QL / QL
  • W = QL / QH - QL
  • W = QL - QH

Questão 110

Questão
Is any non - quasistatic thermodynamic process, the over - all entropy of an isolated system will
Responda
  • increase only
  • decrease only
  • stay the same
  • decrease and then increase

Questão 111

Questão
Entropy is the measure of
Responda
  • randomness or disorder
  • the change in enthalpy of the system
  • the internal energy of the gas
  • the heat capacity of the substance

Questão 112

Questão
For spontaneously occurring natural process in an isolated system, which expression best express dS ?
Responda
  • dS is greater than 0
  • dS equals 0
  • dS is less than zero
  • dS = dQ / T

Questão 113

Questão
Energy changes are represented by all except
Responda
  • dQ rev / T
  • negative integral of VdP
  • mCpdT
  • TdS - PdV

Questão 114

Questão
Work or energy can be a function of all of the following except
Responda
  • force and time
  • force and distance
  • toque and angular acceleration
  • power and time

Questão 115

Questão
U + PV is a quantity called
Responda
  • enthalpy
  • flow energy
  • shaft work
  • entropy

Questão 116

Questão
In flow process, neglecting KE and PE changes, negative integral of Vdp represents
Responda
  • shaft work
  • heat transfer
  • closed system work
  • flow energy

Questão 117

Questão
Power may be expressed in units of
Responda
  • BTU / hr
  • ft - lbs
  • HP - hours
  • KW - hours

Questão 118

Questão
Equilibrium condition exist in all except which of the following ?
Responda
  • 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

Questão 119

Questão
Name the process that has no heat transfer
Responda
  • isentropic
  • isothermal
  • quasistatic
  • polytropic

Questão 120

Questão
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
Responda
  • convergent - divergent
  • diverging
  • converging
  • constant cross section

Questão 121

Questão
Enthalpy of an ideal gas is a function only of
Responda
  • temperature
  • entropy
  • pressure
  • internal energy

Questão 122

Questão
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
Responda
  • pressure is decreased
  • pressure is increased
  • temperature is decrease
  • temperature is decreased and pressure in increased

Questão 123

Questão
The rate of heat transfer through a given section of a uniform wall or a given temperature difference is
Responda
  • 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

Questão 124

Questão
Which of the following metals has the highest specific heat capacity at 100°C ?
Responda
  • aluminum
  • bismuth
  • copper
  • iron

Questão 125

Questão
The radical ion (NO₂)⁻ is called
Responda
  • nitrite
  • nitrate
  • nitride
  • binitrite

Questão 126

Questão
a sample of a substance to which chemical formula can be assigned, whose weight is equal to its formula weight is termed as
Responda
  • mole
  • molecule
  • gram equivalent weight
  • atom

Questão 127

Questão
The number of molecules in 22.4 L of a substance in its gaseous state is called
Responda
  • Avogadro's number
  • Dulong's number
  • Petit's number
  • Graham's number

Questão 128

Questão
Which of the following radioactive decay results in an increased Z or number of protons in the nucleus ?
Responda
  • negative beta decay ( electron emission )
  • alpha decay ( helium nucleus emission )
  • positive beta decay ( positron emission )
  • gamma emission ( photon energy emission )

Questão 129

Questão
The relationship between the extension of a spring and the force required to produce the extension is
Responda
  • F = kx
  • F = ma
  • F = μN
  • F = mv² / r

Questão 130

Questão
The deflection of beam is
Responda
  • 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

Questão 131

Questão
Hard water is water which contains soluble salts of which of the following
Responda
  • calcium
  • sodium
  • sulfur
  • chlorine

Questão 132

Questão
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 ?
Responda
  • 2WL / πD²E
  • WL / πD²E
  • WL / 2πD²E
  • WL / 2E

Questão 133

Questão
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 ?
Responda
  • circumferential
  • longitudinal
  • radial
  • at an angle of 45° to the longitudinal and circumferential directions

Questão 134

Questão
The stress concentration factor
Responda
  • 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

Questão 135

Questão
Poisson's ratio is the ratio of
Responda
  • unit lateral deformation to the unit of longitudinal deformation
  • unit stress to unit strain
  • elastic limit to proportional limit
  • shear strain to compressive strain

Questão 136

Questão
The modulus of rigidity of a steel member is
Responda
  • 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

Questão 137

Questão
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
Responda
  • 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

Questão 138

Questão
Hooke's law for an isotropic homogeneous medium experiencing one dimensional stress is
Responda
  • stress = E ⋅ strain
  • strain = E ⋅ stress
  • strain energy = E ⋅ internal energy
  • Force ⋅ area = E ⋅ change in length / length

Questão 139

Questão
The three moment equation may be used to analyze
Responda
  • continuous beam
  • beam loaded at the third point
  • a three element composite beam
  • a step tapered column

Questão 140

Questão
The area of the shear diagram of a beam between any two points on the beam is equal to the
Responda
  • 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

Questão 141

Questão
Fixing both ends of a simply supported beam that has only a concentrated load at midspan will increase the allowed load by
Responda
  • 100 %
  • 50 %
  • 25 %
  • no change

Questão 142

Questão
Young's modulus of elasticity for a material can be calculated indirectly form which of the following properties of material ?
Responda
  • 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

Questão 143

Questão
Modulus of resilience is
Responda
  • 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

Questão 144

Questão
When a metal is cold worked, all of the following generally occur except
Responda
  • grains become equi - axed
  • ductility increases
  • tensile strength increases
  • recrystallization temperature decreases

Questão 145

Questão
Instrinsic silicon becomes extrinsically conductive, with electrons as majority carriers, when doped with
Responda
  • antimony
  • boron
  • germanium
  • aluminum

Questão 146

Questão
Steel can be strengthened by the following except
Responda
  • annealing
  • quenching and tempering
  • work hardening
  • grain refinement

Questão 147

Questão
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
Responda
  • pearlite
  • austenite
  • bainite
  • cementite

Questão 148

Questão
Which of the following is not a method of non destructive testing of steel castings and forgings ?
Responda
  • chemical analysis
  • radiography
  • magnetic particles
  • ultrasonic

Questão 149

Questão
Compressive strength of fully cured concrete is most directly related to
Responda
  • water - cement ratio
  • sand gravel ratio
  • fineness modulus
  • aggregate gradation

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