The expression THE AIR IS SATURATED means ______.A.the relative humidity is 100%B.the vapor pressure is at its minimum for the prevailing temperatureC.precipitation has commencedD.cloud cover is 100%
The expression THE AIR IS SATURATED means ______.
A.the relative humidity is 100%
B.the vapor pressure is at its minimum for the prevailing temperature
C.precipitation has commenced
D.cloud cover is 100%
相关考题：
If air at 95°Cdry bulb temperature and 50%relative humidity is conditioned to 75°Cdry bulb temperature and 50%relative humidity, it is an example of() A.cooling onlyB.cooling and humidifyingC.cooling and dehumidifyingD.adiabatic(绝热的)cooling
The effective temperature of air is dependent upon ______. I. relative humidity II. air velocityA.I onlyB.II onlyC.Both I and IID.Neither I nor II
The dew point is reached when the ______.A.temperature of the air equals the temperature of the seawaterB.atmospheric pressure is 14.7 lbs. per square inchC.relative humidity reaches 50%D.air becomes saturated with water vapor
A hygrometer is device used for determining ______.A.the absolute temperatureB.atmospheric pressureC.wind velocityD.relative humidity
As the temperature for an air mass decreases, the ______.A.absolute humidity increasesB.relative humidity increasesC.specific humidity increasesD.dew point rises
As the temperature for a given mass of air increases, the ______.A.dew point increasesB.dew point decreasesC.relative humidity increasesD.relative humidity decreases
Fog is likely to occur when there is little difference between the dew point and the ______.A.relative humidityB.air temperatureC.barometric pressureD.absolute humidity
The“three arms of government” of Australia refers to the Parliament，the Executive Government and( ) A.the Judiciary B.the High Court C.the Defense Force D.the Air Force
单选题The expression THE AIR IS SATURATED means（）.Athe relative humidity is 100%Bthe vapor pressure is at its minimum for the prevailing temperatureCprecipitation has commencedDcloud cover is 100%
单选题A re-heater in an air conditioning system functions to （）.Acontrol inlet air temperatureBcontrol inlet air volumeCmaintain relative humidity at 15%Drestore conditioned air temperature to a comfortable level
单选题Compared to a low pressure system，generally the air in a high is（）.Awarmer，less dense，and less stableBcool，more dense，and drierCmuggy and cloudyDextremely moist with high relative humidity
单选题The dew point is reached when the（）.Atemperature of the air equals the temperature of the seawaterBatmospheric pressure is 14.7 lbs. per square inchCrelative humidity reaches 50%Dair becomes saturated with water vapor
单选题The temperature at which the air is saturated with water vapor and below which condensation of water vapor will occur is referred to as the（）.Aprecipitation pointBvapor pointCdew pointDabsolute humidity
单选题Clouds form（）.Aas a mass of warm，humid air rises into the atmosphere and cools，condensing moisture into small dropletsBas winds blow across bodies of water，the sun causes the moisture to be absorbed and move upward forming cloudsCdry air compresses moisture from the atmosphere into cloudsDwhen the relative humidity of the atmosphere is low
问答题Practice 1 Heat loss by sweating depends on the fact that when a liquid evaporates, it absorbs an enormous quantity of heat from its surroundings. Therefore, when I am of sweat evaporate, a great deal of heat is absorbed from the surface of the body in contact with it. 1______ 2______ The first is the amount of movement of air surrounding the body. The second is the amount of water vapor in the air that surrounds the body. 3______ For this reason, sweat evaporates very rapidly on windy days, and the rate of heat loss by sweating is much more than on a still day. This accounts for the fact that hot still days are much less comfortable than hot windy days. In contrast, the sweat evaporates very rapidly on hot windy days, and cools the body quickly and effectively. 4______ When air is carrying the maximum amount of water vapor that it can hold, it is said to be 100% saturated with water vapor. The relative humidity of the air is said to be 100%. Under these conditions the air cannot carry any water, so no water can evaporate. When the relative humidity is high, therefore, sweat cannot evaporate. Instead, it forms large drops and runs off your skin without cooling you. 5______ It is obvious that under these conditions, evaporation will be much more rapid. Therefore, sweating will be much more effective as a method of losing heat from the body. On a hot dry day, sweat evaporates as soon as it is formed, and you feel reasonably cool even though the temperature of your environment is very high.[A] When the air is very dry and carries no water at all, the relative humidity is said to be 0%.[B] The second factor is the amount of water vapor in the air－the humidity.[C] Hot windy days are much more comfortable than hot still days.[D] This heat transfer occurs even if the environment is hotter than the body.[E] When air moves over the surface of water, the amount of evaporation is greatly increased.[F] You might expect the highest incidence of a heat stroke when the maximum temperature is 100 and humidity is 50%.[G] Two factors affect the rate of evaporation of sweat, and therefore the effectiveness of sweating as a method of cooling the body.
单选题When air is at its dew point it is at its（）Alowest absolute humidityBlowest relative humidityChighest absolute humidityDhighest relative humidity
单选题The ratio of the weight of moisture contained in a given volume of air, to the weight of moisture that the same sample would hold if saturated, is called the（）.Aabsolute humidityBrelative humidityCspecific humidityDtotal humidity
单选题Which instrument is used to measure the relative humidity of air?（）AHydrometerBHygrometerCSpectrometerDBarometer
单选题If air at 95℃ dry bulb temperature and 50% relative humidity is conditioned to 75℃ dry bulb temperature and 50% relative humidity, it is an example of （）.Acooling onlyBcooling and humidifyingCcooling and dehumidifyingDadiabatic cooling
单选题The amount of moisture in a given sample of air, when compared with the amount of moisture the air could hold if totally saturated at the existing temperature of the sample, is called （）.Aabsolute humidityBspecific humidityCeffective humidityDrelative humidity
单选题When comparing the air with 50% of relative humidity with the air with 100% of relative humidity, which one will hold more water?（）Athe formerBthe latterCnot for sureDsame each other
单选题To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, you should （）Aadmit only enough fresh outside air to provide proper ventilationBreduce the air reheating system loadClower the compressor head pressureDoperate the purge recovery unit continuously
单选题Relative humidity is the percentage of water vapor that is in the air as compared to the maximum amount it can hold at（）.Aa specific barometric pressureBa specific temperatureCa specific wind speedDany time
单选题A lower thermostatic temperature setting will provide a desired degree of comfort in a room where （）Alow relative humidity is maintainedBtriple banded squirrel cage fans are usedCair circulation is a maximumDhigh relative humidity is maintained
单选题The effective temperature of air is dependent upon（） Ⅰ.relative humidity Ⅱ.air velocityAⅠonlyBⅡonlyCBoth Ⅰand ⅡDNeitherⅠnor Ⅱ
单选题When air is at its dew point it（）.Awill contain no additional moistureBhas the lowest relative humidityCcannot keep up its moistureDhas a low absolute humidity