单选题Which of the following statements is true concerning centrifugal pumps?（）AThey are particularly suited for pumping high viscosity fluidsBThey are started with the discharge valve openedCThe flow of liquid is developed by imparting energy due to the rotation of an impellerDThey are always mounted in a horizontal position
单选题
Which of the following statements is true concerning centrifugal pumps?（）
A
They are particularly suited for pumping high viscosity fluids
B
They are started with the discharge valve opened
C
The flow of liquid is developed by imparting energy due to the rotation of an impeller
D
They are always mounted in a horizontal position
参考解析
解析：
暂无解析
相关考题：
Which of the following statements about Leopold and Rudolph Blaschka is TRUE?A. They were brothers.B. They were artists.C. They were florists.D. They were farmers.
Which of the following statements is true? Accounts payable are ______.A．debts owed to suppliersB．related to purchases of goods on an open accountC．current liabilitiesD．all of the above
All the following statements concerning the nature of language change is true except() A language change is inevitableB language change is abruptC language change is universalD language change is extensive
Which of the following conditions is true concerning a flammable liquid with a concentration above the upper explosive limit?A.The mixture is too lean to burnB.The mixture is too rich to burnC.The vapor is about to explodeD.Conditions are perfect for combustion
Which of the following statements about language is NOT true?A.Language is a system B.Language is symbol C.Animals also have language D.Language is arbitrary
Which of the following concerning natural gas is NOT true？( ) A.It was not favored in the past. B.It is easily affected by the change of the climate. C.People are beginning to realize its value. D.It is increasingly cheaper to be liquefied.
Which of the following statements concerning intellectual property is wrong？（）A、Intellectual property is an intangible creationB、Intellectual property in ludes patents，trademarks，copyrights，etc.C、Intellectual property is a visible creationD、There are some agreement sconcerning intellectual property under the WTO
The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router. Which of the following statements is true concerning this command（）。A、This command should be executed from the global configuration modeB、The IP address 10.121.16.8 is the local router port used to forward dataC、102 is the remote DLCI that will receive the informationD、This command is required for all Frame Relay configurationsE、The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC
Which statements concerning the relationships between the following classes are true？（） class Foo { int num； Baz comp = new Baz（）； } class Bar { boolean flag； } class Baz extends Foo { Bar thing = new Bar（）； double limit； } A、A Bar is a Baz.B、A Foo has a Bar.C、A Baz is a Foo.D、A Foo is a Baz.E、A Baz has a Bar.
单选题Which of the following statements concerning energy is correct?（）AEnergy can be created or destroyedBEnergy may not be transformedCThe total quantity of energy in the universe is always the sameDNone of the above
多选题If p and q are primes greater than 2, which of the following statements must be true? (Indicate all such statements.)Ap + q is evenBpq is oddCp2-q2 is even
多选题Concerning the figure below, if a =b, which of the following statements must be true? (Indicate all such statements.)Ac=dBl and k are parallelCm and l are perpendicular
多选题Which of the following statements are true? (Indicate all such statements.)Aτ(5) =τ(7)Bτ(5) τ(7) =τ(35)Cτ(5) + τ(7) =τ(12)
单选题Which of the following statements concerning cargo is correct?（）ACargoes are any type of goods transported by any type of shipsBCargoes are goods transported in bulkCCargoes usually include goods transported in bulk and in containersDCargoes are usually packaged in containers
单选题Which of the following conditions is true concerning a flammable liquid with a concentration above the upper explosive limit?（）AThe mixture is too lean to burnBThe mixture is too rich to burnCThe vapor is about to explodeDConditions are perfect for combustion
单选题Which of the following statements concerning the water tube and fire tube boilers is not true?（）Anatural circulation of the water in the water tube boiler is better than that in the fire tube boilerBfor the same output the water tube boiler will carry less mass of water compared with the fire tube boilerCthe water tube boiler will cost shorter time for steam raisingDthe water tube boiler require lower skill in operating and maintaining
单选题The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router. Which of the following statements is true concerning this command（）。AThis command should be executed from the global configuration modeBThe IP address 10.121.16.8 is the local router port used to forward dataC102 is the remote DLCI that will receive the informationDThis command is required for all Frame Relay configurationsEThe broadcast option allows packets, such as RIP updates, to be forwarded across the PVC
单选题Which of the following statements is true concerning the overall efficiency of air compressors?（）AHigh pressure compressors are more efficient than low pressure compressorsBMechanical efficiency divided by compressor efficiency will equal the overall efficiency of the compressor unitCTwo stage compressors are generally more efficient than single stage compressorsDThe volumetric efficiency is decreased in multistage compressors
单选题Which of the following statements is true concerning any evaporator?（）AHigh conductivity of the distillate indicates distillate salinity is excessiveBIncreasing the absolute pressure of the shell will increase the distillers capacityCMesh separators are used in evaporators to filter the distillateDReducing the brine density will reduce the heat lost overboard
单选题Which of the following statements concerning fire-tube boilers is correct?（）ACombustion gases flow through the tubesBFlames impinge on the tubesCCombustion occurs in the tubesDWater flows through the tubes
单选题Which of the following statements is true concerning the cetane number of diesel fuel?（）AThe cetane number affects the amount of injection lagBThe cetane number is an indication of the fuels viscosityCIgnition lag is reduced with fuels having a high cetane numberDThe cetane number is of little significance in the combustion process
单选题Which of the following statements is correct concerning the “flash point ” of a liquid?（）AIt is lower than the ignition temperatureBIt is the temperature at which a substance will spontaneously igniteCIt is the temperature at which a substance, when ignited, will continue to bumDIt is the temperature at which the released vapors will fall within the explosive range
单选题Which of the following statements is true concerning an oil cooler?（）AThe oil temperature is less than the cooling water temperatureBThe oil pressure is less than the cooling water pressureCThe oil pressure is greater than the cooling water pressureDThe oil flow control valve is always installed in the oil input line
单选题Which of the following statements concerning fuel atomization in a diesel engine cylinder is correct?（）AThe greater the atomization, the greater the penetrationBThe greater the atomization, the less the penetrationCThe degree of atomization has nothing to do with the degree of penetrationDAtomization and penetration are one and the same
单选题Which of the following statements is true concerning simple parallel resistance circuits?（）AThe total current flow equals the sum of the individual currentsBThe total current flow equals the reciprocal of the sum of the individual currentsCThe total resistance equals the sum of the individual resistanceDThe total voltage equals the sum of the individual voltages across each resistance
单选题Which of the following statements is true concerning Halon 1301 fire extinguishing equipment?（）AThe agent is considered nontoxic at room temperature in low concentrationsBThe agent is less effective than carbon dioxideCHalon primarily extinguishes the fire by coolingDThe agent cannot be used on electrical fires because it leaves a residue
单选题Which of the following statements is correct concerning the viscosity of lubricating oil?（）AViscosity will increase as temperature increasesBViscosity is a measure of a fluid s internal resistance to flowCViscosity will decrease as temperature decreasesDViscosity is not dependent on temperature