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GENERAL ENGINEERING II

Pregunta 1 de 149

1

What type of bond exists predominantly in sodium chloride crystal ?

Selecciona una de las siguientes respuestas posibles:

  • ionic bond

  • metallic bond

  • covalent bond

  • polar bond

Explicación

Pregunta 2 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • increased

  • decreased

  • remains the same

  • decreased up to the midpoint of the transformation and then asymptotically reaches its original value

Explicación

Pregunta 3 de 149

1

Which of the following leads to a reduction in the electrical resistivity of a pure metal ?

Selecciona una de las siguientes respuestas posibles:

  • annealing

  • cold working

  • grain refinement

  • addition of alloying elements

Explicación

Pregunta 4 de 149

1

The rigidity of polymer can be increased by

Selecciona una de las siguientes respuestas posibles:

  • all of these

  • increase in degree of polymerization

  • increase in the extent of cross linking

  • crystallization

Explicación

Pregunta 5 de 149

1

Which of the following properties of a metal is insensitive to microstructure ?

Selecciona una de las siguientes respuestas posibles:

  • modulus of elasticity

  • tensile strength

  • ductility

  • hardness

Explicación

Pregunta 6 de 149

1

The dominant charge carriers in phosphorus - doped silicon crystal at room temperature are

Selecciona una de las siguientes respuestas posibles:

  • electrons

  • electron holes

  • protons

  • silicon ions

Explicación

Pregunta 7 de 149

1

Metals are conductive because

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 8 de 149

1

An X - ray is

Selecciona una de las siguientes respuestas posibles:

  • an electromagnetic radiation

  • a ray of electrons

  • a ray of helium nuclei

  • not known, hence the name " x " ray

Explicación

Pregunta 9 de 149

1

An electron - volt is

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 10 de 149

1

Group IA are easily ionized because

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 11 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 12 de 149

1

Which of the following group of elements all form crystals of diamond structural lattice ?

Selecciona una de las siguientes respuestas posibles:

  • carbon, silicon, germanium

  • carbon, boron, aluminum

  • carbon, cobalt, nickel

  • lithium, sodium, potassium

Explicación

Pregunta 13 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 14 de 149

1

Which of the following material properties is adversely affected by grain refinement ?

Selecciona una de las siguientes respuestas posibles:

  • creep resistance

  • tensile strength

  • ductility

  • elastic module

Explicación

Pregunta 15 de 149

1

Which of the following classes of materials exhibit a decreasing electrical conductivity with increasing temperature ?

Selecciona una de las siguientes respuestas posibles:

  • metals

  • pure ionic materials

  • intrinsic semiconductors

  • p - type semiconductors

Explicación

Pregunta 16 de 149

1

The property that characterizes a material's ability to be drawn into a wire is its

Selecciona una de las siguientes respuestas posibles:

  • ductility

  • tensile strength

  • fatigue endurance limit

  • impact strength

Explicación

Pregunta 17 de 149

1

Which of the following treatments will result in an increase in the fatigue strength of steel ?

Selecciona una de las siguientes respuestas posibles:

  • short peening

  • annealing

  • cold working

  • surface roughening

Explicación

Pregunta 18 de 149

1

In p - type semiconductors, conductivity is provided by

Selecciona una de las siguientes respuestas posibles:

  • the motion of holes

  • the motion of electrons

  • the motion of ions

  • the motion of conductivity

Explicación

Pregunta 19 de 149

1

A photon is

Selecciona una de las siguientes respuestas posibles:

  • a particle of electromagnetic radiation

  • a neutral proton

  • a neutral electron

  • a charge neutron

Explicación

Pregunta 20 de 149

1

Isotopes of an element are atomic species with

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 21 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 22 de 149

1

The electronic configuration, 1s² 2s² 2p⁶ 3s² 3p⁵ is that of

Selecciona una de las siguientes respuestas posibles:

  • a halogen

  • an alkali metal

  • an inert gas

  • a transition metal

Explicación

Pregunta 23 de 149

1

An angstrom unit, commonly used for atomic and sub - atomic distances is equal to

Selecciona una de las siguientes respuestas posibles:

  • 10⁻¹⁰ m

  • 10¹⁰ m

  • 10⁻⁶ m

  • the distance light travels in 10⁻¹⁰ seconds

Explicación

Pregunta 24 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 25 de 149

1

At absolute zero temperature, all the valence electrons in an intrinsic semiconductor

Selecciona una de las siguientes respuestas posibles:

  • are in the valence bond

  • are in the forbidden gap

  • are in the conduction bond

  • are free electrons

Explicación

Pregunta 26 de 149

1

Carrier mobility depends on

Selecciona una de las siguientes respuestas posibles:

  • temperature and the regularity of the crystal structure

  • resistivity

  • conductivity

  • charge per carrier

Explicación

Pregunta 27 de 149

1

The movement of changers from an area of higher carrier concentration to an area of lower concentration is called

Selecciona una de las siguientes respuestas posibles:

  • diffusion

  • gradient

  • mobility

  • recombination

Explicación

Pregunta 28 de 149

1

Which term describes a material whose properties depend on the direction of stress

Selecciona una de las siguientes respuestas posibles:

  • anisotropic

  • isotropic

  • endotropic

  • asymmetrical

Explicación

Pregunta 29 de 149

1

Materials that emit light in the absence of high heat and continue to emit light after the energy source has been removed are called

Selecciona una de las siguientes respuestas posibles:

  • phosphorescent

  • fluorescent

  • semiconductor - laser diodes

  • translucent diodes

Explicación

Pregunta 30 de 149

1

A gamma ray is composed of

Selecciona una de las siguientes respuestas posibles:

  • high energy electromagnetic radiation

  • high energy protons

  • high energy electrons

  • high energy neutrinos

Explicación

Pregunta 31 de 149

1

Plank's constant represents

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 32 de 149

1

The elements exhibit periodically recurring chemical and physical properties because

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 33 de 149

1

Which element about crystal dislocations is incorrect ?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 34 de 149

1

Ions are formed when

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 35 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 36 de 149

1

Avogadro's number represents

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 37 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 38 de 149

1

Which of the following characteristics of the alkaline earth elements is unique

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 39 de 149

1

The chemical formula of the salt formed from the neutralization of potassium hydroxide and sulphuric acid is

Selecciona una de las siguientes respuestas posibles:

  • K₂SO₄

  • NaCl

  • P₂SO₄

  • KSO₄

Explicación

Pregunta 40 de 149

1

The chemical formula of the most common compound formed from beryllium and iodine is

Selecciona una de las siguientes respuestas posibles:

  • BeI₂

  • Be₂I₇

  • BeI

  • Be₇I₂

Explicación

Pregunta 41 de 149

1

Which of the following statements about the halogens is incorrect ?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 42 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 43 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 44 de 149

1

For this reaction, the equilibrium conditions are
H₂ + I₂ = 2HI ΔH = -7.9 KJ

Selecciona una de las siguientes respuestas posibles:

  • temperature and concentration

  • pressure, temperature and concentration

  • pressure only

  • temperature only

Explicación

Pregunta 45 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 46 de 149

1

A close system experiences a reversible process where heat rejection is the only energy transfer. The entropy change

Selecciona una de las siguientes respuestas posibles:

  • must be negative

  • must be zero

  • must be positive

  • is equal to the heat transfer

Explicación

Pregunta 47 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 100 %

  • 25 %

  • 0 %

  • 50 %

Explicación

Pregunta 48 de 149

1

If the temperature of a medium is 0°C, what will be the temperature if it is doubled ?

Selecciona una de las siguientes respuestas posibles:

  • 273°C

  • 0°C

  • 524°R

  • 460°R

Explicación

Pregunta 49 de 149

1

The compression ignition cycle is modeled by which ideal cycle ?

Selecciona una de las siguientes respuestas posibles:

  • diesel cycle

  • otto cycle

  • rankine cycle

  • brayton cycle

Explicación

Pregunta 50 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • temperature only

  • pressure only

  • volume only

  • there cannot be any heat transfer

Explicación

Pregunta 51 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • heat of reaction

  • specific heat

  • heat of vaporization

  • heat of formation

Explicación

Pregunta 52 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 53 de 149

1

An open system First Law should be utilized for all of the following except

Selecciona una de las siguientes respuestas posibles:

  • a piston - cylinder device

  • a nozzle

  • a turbine

  • a compressor

Explicación

Pregunta 54 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • the temperature is quadrupled

  • the pressure is halved

  • the volume is doubled

  • the process is irreversible

Explicación

Pregunta 55 de 149

1

An adiabatic process is characterized by which of the following ?

Selecciona una de las siguientes respuestas posibles:

  • the heat transfer is zero

  • the entropy change is zero

  • the work is zero

  • it is reversible

Explicación

Pregunta 56 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • equal to zero

  • equal to the heat transter

  • equal to the volume times the change in pressure

  • equal to the change in internal energy

Explicación

Pregunta 57 de 149

1

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 ?

Selecciona una de las siguientes respuestas posibles:

  • second law of thermodynamics

  • conservation of mass

  • first law of thermodynamics

  • zeroth law of thermodynamics

Explicación

Pregunta 58 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 59 de 149

1

The steam power cycle is modeled by the ideal cycle known as the

Selecciona una de las siguientes respuestas posibles:

  • rankine cycle

  • otto cycle

  • diesel cycle

  • brayton cycle

Explicación

Pregunta 60 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • throttling process

  • an isothermal process

  • a compression process

  • an isochoric process

Explicación

Pregunta 61 de 149

1

In the case of regenerative gas turbine engine, which of the following is false ?

Selecciona una de las siguientes respuestas posibles:

  • 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 %

Explicación

Pregunta 62 de 149

1

For an ideal turbojet, all of the following statements are true except

Selecciona una de las siguientes respuestas posibles:

  • 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 %

Explicación

Pregunta 63 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 64 de 149

1

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 ?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 65 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 66 de 149

1

The simplified continuity equation ∇V = 0 is not valid for

Selecciona una de las siguientes respuestas posibles:

  • steady compressible flow

  • steady incompressible flow

  • unsteady incompressible flow

  • steady rotational incompressible flow

Explicación

Pregunta 67 de 149

1

How many electrons are there in the outermost octate of a chlorine atom ?

Selecciona una de las siguientes respuestas posibles:

  • 7

  • 1

  • 3

  • 8

Explicación

Pregunta 68 de 149

1

Heat transferred at constant volume process to the thermodynamic system of a fixed mass. The thermodynamic system will produce

Selecciona una de las siguientes respuestas posibles:

  • zero work

  • small amount of work

  • negative work

  • positive work

Explicación

Pregunta 69 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 1.0

  • 0

  • 0.5

  • 0.75

Explicación

Pregunta 70 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • Qp is greater than Qv

  • Qp = Qv

  • Qp is less than Qv

  • Qp = Qv - ΔU

Explicación

Pregunta 71 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • impossible

  • possible

  • irreversible

  • reversible

Explicación

Pregunta 72 de 149

1

Which of the following instruments for measuring fluid velocity does not need to be calibrated ?

Selecciona una de las siguientes respuestas posibles:

  • pitot static tube

  • orifice meter

  • venture tube

  • weir

Explicación

Pregunta 73 de 149

1

Capillarity or the rise or fall of liquid in a thin tube is primarily controlled by which fluid property ?

Selecciona una de las siguientes respuestas posibles:

  • surface tension

  • viscosity

  • density

  • temperature

Explicación

Pregunta 74 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • zero

  • 2

  • K

Explicación

Pregunta 75 de 149

1

Cavitation in fluid mechanics refers to

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 76 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • - Vdp

  • pdV

  • Vdp + pdV

  • Vdp - pdV

Explicación

Pregunta 77 de 149

1

The reheat rankine cycle is proposed to decrease

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 78 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 79 de 149

1

Which of the following statements defines best the capitalized cost ?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 80 de 149

1

Which of the following is not taken into account in making an economic decision between two alternative equipment ?

Selecciona una de las siguientes respuestas posibles:

  • reliability

  • operating cost

  • rate of return

  • salvage value

Explicación

Pregunta 81 de 149

1

A heat sink will dissipate heat energy more rapidly if

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 82 de 149

1

A reference frame which remains fixed while fluid flows through is called

Selecciona una de las siguientes respuestas posibles:

  • Eulerian

  • Lagrangian

  • Stokesian

  • A Navier - Stokes reference frame

Explicación

Pregunta 83 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 84 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 85 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 86 de 149

1

Effective interest rate per year is defined as

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 87 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 88 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 89 de 149

1

Which of the following is not a unit of pressure ?

Selecciona una de las siguientes respuestas posibles:

  • kg / m²

  • Pa

  • bars

  • N / m²

Explicación

Pregunta 90 de 149

1

Which of the following is the definition of Joule ?

Selecciona una de las siguientes respuestas posibles:

  • N - m

  • a unit of power

  • kg - m / s²

  • rate of change of energy

Explicación

Pregunta 91 de 149

1

Which of the following relations defines enthalpy ?

Selecciona una de las siguientes respuestas posibles:

  • H = U + PV

  • H = U + P / T

  • H = U + P / V

  • H = PV + T

Explicación

Pregunta 92 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 93 de 149

1

What is the actual shape of the methane CH₄ molecule ?

Selecciona una de las siguientes respuestas posibles:

  • a tetrahedral

  • linear

  • square planar

  • pyramidal

Explicación

Pregunta 94 de 149

1

What is the oxidation state of the nitrogen in NO₃⁻ ?

Selecciona una de las siguientes respuestas posibles:

  • + 5

  • - 1

  • + 3

  • + 1

Explicación

Pregunta 95 de 149

1

What is the oxidation number of Cr in the dicromate ion (Cr₂O₇) ²⁻

Selecciona una de las siguientes respuestas posibles:

  • + 6

  • - 1

  • 0

  • 7

Explicación

Pregunta 96 de 149

1

Reactions generally proceed faster at higher temperature because of which of the following ?

Selecciona una de las siguientes respuestas posibles:

  • the activation energy is less

  • the molecules are less energetic

  • the bonds are easier to break

  • the molecules collide more frequently

Explicación

Pregunta 97 de 149

1

Determine the height of the centroid of the semi - circle with radius r from its diameter

Selecciona una de las siguientes respuestas posibles:

  • 4r / 3π

  • 2r / 3

  • 2πr /3

  • 3r / 4π

Explicación

Pregunta 98 de 149

1

What are valence electrons ?

Selecciona una de las siguientes respuestas posibles:

  • the outer shell electrons

  • electrons with positive charge

  • the electrons of complete quantum shells

  • the K - quantum shell electrons

Explicación

Pregunta 99 de 149

1

What is the strong bond between hydrogen atoms known as ?

Selecciona una de las siguientes respuestas posibles:

  • covalent bond

  • ionic bond

  • metallic bond

  • ionic and metallic bond

Explicación

Pregunta 100 de 149

1

What are Van der Waals forces ?

Selecciona una de las siguientes respuestas posibles:

  • weak secondary bonds between atoms

  • primary bonds between atoms

  • forces between electrons and protons

  • forces present only in gases

Explicación

Pregunta 101 de 149

1

Compare the metallic iron form Fe and the ferric ions Fe²⁺ and Fe³⁺. Which has the smallest atomic radius of the same temperature ?

Selecciona una de las siguientes respuestas posibles:

  • Fe³⁺

  • Fe²⁺

  • Fe

  • they have the same radii

Explicación

Pregunta 102 de 149

1

Polymers that favor crystallization are least likely to have which of the following

Selecciona una de las siguientes respuestas posibles:

  • an atactic configuration of side group

  • small side group

  • only one repeating unit

  • small chain length

Explicación

Pregunta 103 de 149

1

In general, what are the effects of cold working a metal ?

Selecciona una de las siguientes respuestas posibles:

  • increase strength, decrease ductility

  • increase strength, increase ductility

  • decrease strength, decrease ductility

  • decrease strength, increase ductility

Explicación

Pregunta 104 de 149

1

Which of the following is not structural class steel ?

Selecciona una de las siguientes respuestas posibles:

  • tool and die

  • carbon

  • stainless

  • low - alloy

Explicación

Pregunta 105 de 149

1

Which of the following phases of steel has face - centered cubic structure ?

Selecciona una de las siguientes respuestas posibles:

  • austenite

  • ferrite

  • pearlite

  • martensite

Explicación

Pregunta 106 de 149

1

The state of a thermodynamic system is always defined by its

Selecciona una de las siguientes respuestas posibles:

  • properties

  • absolute temperature

  • process

  • temperature and pressure

Explicación

Pregunta 107 de 149

1

Mathematically, a thermodynamic property is which of the following ?

Selecciona una de las siguientes respuestas posibles:

  • a point function

  • a path function

  • an exact differential

  • discontinuous

Explicación

Pregunta 108 de 149

1

The first law of thermodynamics states that

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 109 de 149

1

In terms of QH and QL, the network of a carnot cycle is

Selecciona una de las siguientes respuestas posibles:

  • W = QH - QL

  • W = QH - QL / QL

  • W = QL / QH - QL

  • W = QL - QH

Explicación

Pregunta 110 de 149

1

Is any non - quasistatic thermodynamic process, the over - all entropy of an isolated system will

Selecciona una de las siguientes respuestas posibles:

  • increase only

  • decrease only

  • stay the same

  • decrease and then increase

Explicación

Pregunta 111 de 149

1

Entropy is the measure of

Selecciona una de las siguientes respuestas posibles:

  • randomness or disorder

  • the change in enthalpy of the system

  • the internal energy of the gas

  • the heat capacity of the substance

Explicación

Pregunta 112 de 149

1

For spontaneously occurring natural process in an isolated system, which expression best express dS ?

Selecciona una de las siguientes respuestas posibles:

  • dS is greater than 0

  • dS equals 0

  • dS is less than zero

  • dS = dQ / T

Explicación

Pregunta 113 de 149

1

Energy changes are represented by all except

Selecciona una de las siguientes respuestas posibles:

  • dQ rev / T

  • negative integral of VdP

  • mCpdT

  • TdS - PdV

Explicación

Pregunta 114 de 149

1

Work or energy can be a function of all of the following except

Selecciona una de las siguientes respuestas posibles:

  • force and time

  • force and distance

  • toque and angular acceleration

  • power and time

Explicación

Pregunta 115 de 149

1

U + PV is a quantity called

Selecciona una de las siguientes respuestas posibles:

  • enthalpy

  • flow energy

  • shaft work

  • entropy

Explicación

Pregunta 116 de 149

1

In flow process, neglecting KE and PE changes, negative integral of Vdp represents

Selecciona una de las siguientes respuestas posibles:

  • shaft work

  • heat transfer

  • closed system work

  • flow energy

Explicación

Pregunta 117 de 149

1

Power may be expressed in units of

Selecciona una de las siguientes respuestas posibles:

  • BTU / hr

  • ft - lbs

  • HP - hours

  • KW - hours

Explicación

Pregunta 118 de 149

1

Equilibrium condition exist in all except which of the following ?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 119 de 149

1

Name the process that has no heat transfer

Selecciona una de las siguientes respuestas posibles:

  • isentropic

  • isothermal

  • quasistatic

  • polytropic

Explicación

Pregunta 120 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • convergent - divergent

  • diverging

  • converging

  • constant cross section

Explicación

Pregunta 121 de 149

1

Enthalpy of an ideal gas is a function only of

Selecciona una de las siguientes respuestas posibles:

  • temperature

  • entropy

  • pressure

  • internal energy

Explicación

Pregunta 122 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • pressure is decreased

  • pressure is increased

  • temperature is decrease

  • temperature is decreased and pressure in increased

Explicación

Pregunta 123 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 124 de 149

1

Which of the following metals has the highest specific heat capacity at 100°C ?

Selecciona una de las siguientes respuestas posibles:

  • aluminum

  • bismuth

  • copper

  • iron

Explicación

Pregunta 125 de 149

1

The radical ion (NO₂)⁻ is called

Selecciona una de las siguientes respuestas posibles:

  • nitrite

  • nitrate

  • nitride

  • binitrite

Explicación

Pregunta 126 de 149

1

a sample of a substance to which chemical formula can be assigned, whose weight is equal to its formula weight is termed as

Selecciona una de las siguientes respuestas posibles:

  • mole

  • molecule

  • gram equivalent weight

  • atom

Explicación

Pregunta 127 de 149

1

The number of molecules in 22.4 L of a substance in its gaseous state is called

Selecciona una de las siguientes respuestas posibles:

  • Avogadro's number

  • Dulong's number

  • Petit's number

  • Graham's number

Explicación

Pregunta 128 de 149

1

Which of the following radioactive decay results in an increased Z or number of protons in the nucleus ?

Selecciona una de las siguientes respuestas posibles:

  • negative beta decay ( electron emission )

  • alpha decay ( helium nucleus emission )

  • positive beta decay ( positron emission )

  • gamma emission ( photon energy emission )

Explicación

Pregunta 129 de 149

1

The relationship between the extension of a spring and the force required to produce the extension is

Selecciona una de las siguientes respuestas posibles:

  • F = kx

  • F = ma

  • F = μN

  • F = mv² / r

Explicación

Pregunta 130 de 149

1

The deflection of beam is

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 131 de 149

1

Hard water is water which contains soluble salts of which of the following

Selecciona una de las siguientes respuestas posibles:

  • calcium

  • sodium

  • sulfur

  • chlorine

Explicación

Pregunta 132 de 149

1

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 ?

Selecciona una de las siguientes respuestas posibles:

  • 2WL / πD²E

  • WL / πD²E

  • WL / 2πD²E

  • WL / 2E

Explicación

Pregunta 133 de 149

1

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 ?

Selecciona una de las siguientes respuestas posibles:

  • circumferential

  • longitudinal

  • radial

  • at an angle of 45° to the longitudinal and circumferential directions

Explicación

Pregunta 134 de 149

1

The stress concentration factor

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 135 de 149

1

Poisson's ratio is the ratio of

Selecciona una de las siguientes respuestas posibles:

  • unit lateral deformation to the unit of longitudinal deformation

  • unit stress to unit strain

  • elastic limit to proportional limit

  • shear strain to compressive strain

Explicación

Pregunta 136 de 149

1

The modulus of rigidity of a steel member is

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 137 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 138 de 149

1

Hooke's law for an isotropic homogeneous medium experiencing one dimensional stress is

Selecciona una de las siguientes respuestas posibles:

  • stress = E ⋅ strain

  • strain = E ⋅ stress

  • strain energy = E ⋅ internal energy

  • Force ⋅ area = E ⋅ change in length / length

Explicación

Pregunta 139 de 149

1

The three moment equation may be used to analyze

Selecciona una de las siguientes respuestas posibles:

  • continuous beam

  • beam loaded at the third point

  • a three element composite beam

  • a step tapered column

Explicación

Pregunta 140 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 141 de 149

1

Fixing both ends of a simply supported beam that has only a concentrated load at midspan will increase the allowed load by

Selecciona una de las siguientes respuestas posibles:

  • 100 %

  • 50 %

  • 25 %

  • no change

Explicación

Pregunta 142 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 143 de 149

1

Modulus of resilience is

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 144 de 149

1

When a metal is cold worked, all of the following generally occur except

Selecciona una de las siguientes respuestas posibles:

  • grains become equi - axed

  • ductility increases

  • tensile strength increases

  • recrystallization temperature decreases

Explicación

Pregunta 145 de 149

1

Instrinsic silicon becomes extrinsically conductive, with electrons as majority carriers, when doped with

Selecciona una de las siguientes respuestas posibles:

  • antimony

  • boron

  • germanium

  • aluminum

Explicación

Pregunta 146 de 149

1

Steel can be strengthened by the following except

Selecciona una de las siguientes respuestas posibles:

  • annealing

  • quenching and tempering

  • work hardening

  • grain refinement

Explicación

Pregunta 147 de 149

1

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

Selecciona una de las siguientes respuestas posibles:

  • pearlite

  • austenite

  • bainite

  • cementite

Explicación

Pregunta 148 de 149

1

Which of the following is not a method of non destructive testing of steel castings and forgings ?

Selecciona una de las siguientes respuestas posibles:

  • chemical analysis

  • radiography

  • magnetic particles

  • ultrasonic

Explicación

Pregunta 149 de 149

1

Compressive strength of fully cured concrete is most directly related to

Selecciona una de las siguientes respuestas posibles:

  • water - cement ratio

  • sand gravel ratio

  • fineness modulus

  • aggregate gradation

Explicación