网友您好, 请在下方输入框内输入要搜索的题目:
题目内容
(请给出正确答案)
单选题
Compared to a low pressure system,generally the air in a high is().
A
warmer,less dense,and less stable
B
cool,more dense,and drier
C
muggy and cloudy
D
extremely moist with high relative humidity
参考答案
参考解析
解析:
暂无解析
更多 “单选题Compared to a low pressure system,generally the air in a high is().A warmer,less dense,and less stableB cool,more dense,and drierC muggy and cloudyD extremely moist with high relative humidity” 相关考题
考题
Low compressor head pressure in a refrigeration system can be caused by ___.A.insufficient condenser cooling waterB.excessive condenser cooling waterC.air in the refrigeration systemD.excessive refrigerant in the system
考题
Restrictions occurring in the small orifices(孔) of pneumatic control system components can be caused by ______.A.moisture in the compressed air supplyB.excessive dryness in the compressed air supplyC.pressure surging in the compressed air receiverD.insufficient lubrication of the system components
考题
The refrigeration system low pressure cutout switch is actuated by______.A.an electric system managerB.a sensing bulb at the tail coil of the evaporatorC.pressure changes in the suction lineD.failure of the king solenoid valve
考题
A generally circular low pressure area is called a(n)______.A.cycloneB.anticycloneC.cold frontD.occluded front
考题
A low in a marine weather report is an air pressure system the pressure at the center of which is ______.A.the highest over the areaB.the lowest over the areaC.higher than 1013 HPAD.lower than 1013 HPA
考题
单选题Which of the following statements describes the function of an expansion tank in a diesel engine cooling system?()A
Maintains a constant head on the systemB
Reduces the likelihood of air or steam pockets formationC
Provides a low pressure point for the addition of makeup cooling waterD
All of the above
考题
单选题An increase in diesel engine crankcase pressure generally indicates excessive()A
compression pressureB
lube oil header pressureC
scavenge air pressureD
piston ring blow-by
考题
单选题Generally speaking,you should expect to find low atmospheric pressure prevailing in the earth’s().A
equatorial areaB
polar regionsC
mid-latitudesD
All of the above
考题
单选题In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of ()A
broken valve springsB
tight drive beltsC
high line voltageD
air in the system
考题
单选题Cast irons weakness in tension and under shock loading limits its use to low pressure steam, air, oil and low speed water fittingsThe above sentence, most probably means ().A
cast iron has weaknessB
cast iron can stand up shock loadingC
cast iron fittings are only suitable in low pressure situationD
east iron fittings are not suitable in low pressure situation
考题
单选题Which of the following statements is true concerning the overall efficiency of air compressors?()A
High pressure compressors are more efficient than low pressure compressorsB
Mechanical efficiency divided by compressor efficiency will equal the overall efficiency of the compressor unitC
Two stage compressors are generally more efficient than single stage compressorsD
The volumetric efficiency is decreased in multistage compressors
考题
单选题The loss of the diesel engine cylinder air charge through leaky valves, piston rings, worn or scored liners, would be indicated by which of the following sets of conditions?()A
Low compression pressure and high exhaust temperatureB
Low firing pressure and high exhaust temperatureC
Low compression pressure and low exhaust temperatureD
Low firing pressure and low exhaust temperature
考题
单选题An air mass is termed warm if().A
it is above 70°FB
the ground over which it moves is cooler than the airC
it originated in a high pressure areaD
it originated in a low pressure area
考题
单选题A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently chargedIt is generally located in the().A
high pressure liquid lineB
low pressure liquid lineC
high pressure vapor lineD
low pressure vapor line
考题
单选题Which instrument is used to predict the approach of a low pressure system().A
AnemometerB
FathometerC
BarometerD
Thermometer
考题
单选题A generally circular low pressure area is called a(n)().A
cycloneB
anticycloneC
cold frontD
occluded front
考题
单选题The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch()A
system is overcharged with refrigerantB
system is low on refrigerantC
discharge valves are leaking excessivelyD
discharge valves are leaking slightly
考题
单选题Low pressure air is usually taken through () or pressure regulators to a low pressure reservoir supplying a ring main through driers.A
globe valvesB
butterfly valvesC
gate valvesD
reducing valves
考题
单选题The greater the pressure difference between a high and a low pressure center,the().A
dryer the air mass will beB
cooler the temperature will beC
greater the force of the wind will beD
warmer the temperature will be
考题
单选题The purpose of the refrigeration system low pressure cutout switch is to ()A
protect the compressor from liquid flood backB
protect the compressor from low discharge pressureC
start and stop the compressor upon system demandD
start the compressor after a drop in the evaporator pressure
考题
单选题If an air compressor is used to supply compressed air to outlets throughout the engine room and on deck of a vessel, the system is known as the ().A
combustion control air systemB
supply air systemC
ships service air systemD
low pressure deck air system
考题
单选题An un-loader is installed on an air compressor to ().A
bypass the high pressure stage to the low pressure stage on 100% of the air compressors in serviceB
prevent excessive inter-stage pressure buildupC
control compressor discharge pressureD
remove all but the frictional load during starting
考题
单选题While troubleshooting a refrigeration system for low head pressure, liquid refrigerant flooding back from the evaporator is determined to be the causeIt may be necessary to ().A
change the expansion valve adjustmentB
readjust the water regulating valve to increase the flow of waterC
purge air from the condenserD
clean the waterside of the condenser
考题
单选题Pump up the starting air reservoirs to their maximum pressure and ()the air reservoirs and air system.A
openB
closeC
drainD
vent
考题
单选题A crew member reports that the high-pressure alarm light of a low-pressure CO2 fixed fire extinguishing system is illuminated. The most probable cause of this condition would be that().A
an air leak has developed in the tankB
the tank cooling system has malfunctionedC
the pilot cylinder discharge valve is leakingD
an excessive amount of insulation has been installed on the tank and piping
考题
单选题An indication of a diesel engine air intake being partially clogged, is ().A
low firing pressure and low exhaust temperaturesB
low firing pressure and normal exhaust temperaturesC
high firing pressure and low exhaust temperaturesD
high firing pressure and high exhaust temperatures
考题
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by().A
leaky discharge valves on the LP cylinderB
leaky discharge valves on the HP cylinderC
insufficient intercooler coolingD
low ambient air pressure
热门标签
最新试卷