When an unsaturated air-water mixture is heated at constant pressure,
then
(A) The partial pressure of water vapour increases
(B) The specific humidity decreases
(C) The relative humidity increases
(D) The relative humidity decreases
D) The relative humidity decreases
Description : With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature). (A) Increases (B) Remains unchanged (C) Decreases (D) Decreases linearly
Last Answer : (A) Increases
Description : The ratio of partial pressure of water vapour in a mixture to the saturation pressure of water at the same temperature of the mixture is called as A. humidity B. partial humidity C. specific humidity D. relative humidity
Last Answer : ANSWER : D
Description : During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the __________ remains ... pressure of water vapor (C) Relative humidity (D) None of these
Last Answer : (A) Wet bulb temperature
Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Description : On a day when the partial pressure of water vapor remains constant, what happens as the temperature rises? a. the relative humidity increases b. the relative humidity decreases c. the relative humidity remains constant d. the air would eventually become saturated
Last Answer : the relative humidity decreases
Description : Which of the following decreases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) None of these
Last Answer : (D) None of these
Description : Which of the following increases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Which of the following remains constant during evaporative cooling process with recirculated water supply? (A) Relative humidity (B) Partial pressure of vapour (C) Wet bulb temperature (D) None of these
Last Answer : (C) Wet bulb temperature
Description : Which of the following remains constant during sensible cooling process? (A) Specific humidity (B) Partial pressure of vapour (C) Both (A) and (B)
Last Answer : (C) Both (A) and (B)
Description : Relative humidity is the ratio of the (A) Partial pressure of the vapour to the vapour pressure of the liquid at room temperature (B) Partial pressure of the vapour to the vapour pressure of the liquid at gas temperature (C) Actual humidity to saturation humidity (D) None of these
Last Answer : (B) Partial pressure of the vapour to the vapour pressure of the liquid at gas temperatur
Description : At a fixed total pressure, humidity depends only on the (A) Partial pressure of vapour in the mixture (B) Heat capacity of the vapour (C) Density of the vapour (D) None of these
Last Answer : (A) Partial pressure of vapour in the mixture
Description : At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent. (A) 100 (B) 0 (C) 50 (D) Between 0 and 100
Last Answer : (B) 0
Description : Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C ... (B) Heating only (C) Both heating and humidification (D) Evaporative cooling
Last Answer : (C) Both heating and humidification
Description : Fugacity of a component in an ideal gas mixture is equal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at constant pressure and ... increases. (A) Decreases (B) Decreases exponentially (C) Increases (D) Remain constant
Last Answer : (C) Increases
Description : When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the (A) Partial pressure of water vapour is less than the total pressure (B) Humidity is < 100% & dew ... Dew point temperature of air has not reached & air is not saturated fully (D) Air is fully saturated
Last Answer : (D) Air is fully saturated
Description : Dew point of an air-water vapor mixture (A) Decreases with decrease in pressure (B) At constant humidity & total pressure is fixed (C) Corresponding to any point on the humidity chart is obtained by projecting a ... to the temperature axis and to the saturation curve (D) All 'a', 'b' & 'c'
Last Answer : (D) All 'a', 'b' & 'c'
Description : The relative volatility of a binary mixture at constant temperature __________ the total pressure. (A) Decreases with increase in (B) Increases with increase in (C) Is independent of (D) None of these
Last Answer : (A) Decreases with increase in
Description : Air at a particular humidity is heated in a furnace. The new dew point (A) Decreases (B) Increases (C) Depends on the extent of heating (D) Remain unchanged
Last Answer : (B) Increases
Description : The mass of water vapour per unit volume of air is known as - (1) relative humidity (2) specific humidity (3) absolute humidity (4) variable humidity
Last Answer : (3) absolute humidity Explanation: Absolute humidity is the measure of water vapor (moisture) in the air, regardless of temperature. It is expressed as grams of moisture per cubic meter of air (g/m3).
Description : Amount of water vapour (gaseous) in a given volume of air (cubic metre) is known as: (1) Mixing ratio (2) Relative humidity (3) Absolute humidity (4) Specific humidity
Last Answer : (3) Absolute humidity Explanation: The relative humidity of air at a given temperature is the ratio of mass of water vapour actually present in a certain volume of air to the mass of water vapour required to saturate the same volume of air at the same temperature, multiplied by 100.
Description : Amount of water vapour in a unit volume (Cubic metre) of air is called: (1) Mixed ratio (2) relative humidity (3) absolute humidity (4) specific humidity
Description : The actual mass of water vapour present in a given volume of moist air is — a. Relative humidity b. Absolute humidity c. Specific humidity d. All of these
Last Answer : b. Absolute humidity
Last Answer : Absolute humidity
Description : The wet and 'dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be __________ °C. (A) 25 (B) > 25 (C) < 25 (D) - 25
Last Answer : (B) > 25
Description : What is the specific humidity? A. the ratio of the mass of water vapour to the mass of the total mixture of air and water vapour B. the ratio of the mass of dry air to the mass of the total mixture ... ratio of the mass of water vapour to the mass of dry air in a mixture of air and water vapour
Description : Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a (A) Higher dew point (B) Higher absolute (specific) humidity (C) Higher relative humidity (D) Higher wet bulb temperature
Last Answer : (C) Higher relative humidity
Description : Which of the following can be calculated theoretically using steam table and Dalton's law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known? (A) Dew point (B) Humidity ratio (C) Wet bulb temperature (D) None of these
Description : Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled (A) And ... (C) At the same relative humidity (D) And dehumidified with decrease in wet bulb temperature
Last Answer : (D) And dehumidified with decrease in wet bulb temperature
Description : An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively ... air is: (A) 0.048 (B) 0.079 (C) 0.122 (D) 0.152
Last Answer : (D) 0.152
Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above
Last Answer : ANSWER : B
Description : If the temperature of a piece increases suddenly, the relative humidity– (1) increases (2) decreases (3) remains constant (4) fluctuates
Last Answer : (2) decreases Explanation: Relative humidity is the ratio of the partial pressure of water vapour in a airwater mixture to the saturated vapour pressure of water at a specific temperature.
Description : If the temperature of a place increases suddenly, the relative humidity – (1) Increases (2) Decreases (3) Remains constant (4) Fluctuates
Last Answer : (2) Decreases Explanation: Relative humidity is the ratio of the partial pressure of water vapor in an airwater mixture to the saturated vapor pressure of water at a prescribed ... of the system decreases because the saturated vapor pressure of water increases with increasing temperature.
Description : If the temperature of a place increases suddenly, the relative humidity (1) Increases (2) Decreases (3) Remains constant (4) Fluctuates
Last Answer : Decreases
Description : Dew point of a gas-vapour mixture (A) Increases with temperature rise (B) Decreases with temperature rise (C) Decreases with decrease in pressure (D) Increases with increase in pressure
Last Answer : (C) Decreases with decrease in pressure
Description : During sensible heating of humid air (A) Relative humidity increases (B) Dew point remains constant (C) Dry bulb & wet bulb temperature increases (D) Both 'b' & 'c'
Last Answer : (D) Both 'b' & 'c'
Description : __________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity
Last Answer : Option A
Description : . In chemical dehumidification of air (A) Both specific humidity & dry bulb temperature increases (B) Both specific humidity & dry bulb temperature decreases (C) Specific humidity decreases & dry bulb temperature increases (D) Specific humidity increases & dry bulb temperature decreases
Last Answer : (C) Specific humidity decreases & dry bulb temperature increases
Description : Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent? (A) Cooling and dehumidification ... (C) Dehumidification with dry bulb temperature remaining constant (D) None of these
Last Answer : (B) Heating and dehumidification at almost constant wet bulb temperature
Description : When the __________ the relative humidity of air decreases, despite an increase in the absolute humidity. (A) Temperature rises (B) Pressure rises (C) Temperature falls (D) Pressure falls
Last Answer : (A) Temperature rises
Description : The relative humidity of air decreases in-spite of an increase in the absolute humidity, when the (A) Temperature rises (B) Pressure rises (C) Temperature falls (D) Pressure falls
Description : When the liquid phase and vapour phase of a binary system obeys Raoult's and Dalton's law respectively, the relative volatility is the ratio of (A) Vapour pressure of component A to that of ... to the partial pressure of A (D) Partial pressure of component A to the total pressure
Last Answer : (A) Vapour pressure of component A to that of component B
Description : During sensible cooling process (A) Relative humidity decreases (B) Relative humidity increases (C) Wet bulb temperature decreases (D) Both (B) and (C)
Description : Condensation of a vapour-gas mixture just begins, when (where, p = partial pressure of the vapour P = vapour pressure of the liquid). (A) p = P (B) p >>P (C) p < P (D) p
Last Answer : (A) p = P
Description : _________is the partial pressure of water vapor at the existing temperature divided by the equilibrium vapor pressure of water at the existing temperature. a. vacuum pressure b. relative humidity c. absolute pressure d. vapor pressure
Last Answer : relative humidity
Description : Relative humidity is a) the ratio of water vapour in the air compared to the total amount water vapour the air could contain at a given temperature b) equal to the dry bulb temperature divided by the wet bulb ... of dry air e) the ratio of the mass of water vapour divided by the mass of wet air
Last Answer : ANSWER : A
Description : Steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is called the __________ temperature. (A) Dry-bulb (B) Wet-bulb (C) Dew point (D) Adiabatic saturation
Last Answer : (B) Wet-bulb
Description : Relative humidity is the ratio of actual vapour pressure to the saturation vapour pressure (A) At the same temperature (B) At the same pressure (C) In the same volume (D) In the atmosphere
Last Answer : Answer: Option A
Description : Pick up the correct statement from the following: (A) Absolute humidity at a given temperature is equal to weight of moisture present in a unit volume (B) Relative humidity is the ratio of ... of vapours which could be contained at the same temperature when fully saturated (D) All the above
Last Answer : Answer: Option D
Description : The lysimeter helps in the estimation of (1) Evapotranspiration (2) Relative humidity (3) Vapour pressure (4) Wind direction
Last Answer : Evapotranspiration
Description : When humidity ratio of air ____ air is said to be dehumidified. A. increases B. decreases C. remains constant D. none of the mentioned