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 to the air with a wet

bulb temperature of 60°C, then both the approach & the range would be 10°C

(C) For unsaturated air-water vapor mixture at atmospheric conditions, the

wet bulb temperature & adiabatic cooling lines are the same

(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

1 Answer

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

Related questions

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Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

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 : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

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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

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Description : __________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity

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Description : The dew point temperature lines on psychrometric charts are straight inclined sloping downwards to the right. When relative humidity of moist air is 100%, then (A) Wet bulb temperature=dry bulb temperature (B) ... temperature (C) Saturation temperature=dew point temperature (D) All 'a', 'b' & 'c

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Description : __________ temperature remains constant during adiabatic saturation process of unsaturated air. (A) Dew point (B) Dry bulb (C) Wet bulb (D) None of these

Last Answer : (C) Wet bulb

Description : The difference of wet bulb temperature and adiabatic saturation temperature of unsaturated mixture of any system is (A) +ve (B) -ve (C) Zero (D) None of these

Last Answer : (A) +ve

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

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Description : __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid. (A) Dew point (B) Bubble point (C) Dry bulb temperature (D) Wet bulb temperature

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Description : The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

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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

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Description : The relative saturation of a partially saturated mixture of vapour and gas can be increased by __________ of the mixture. (A) Reducing the total pressure (B) Increasing the total pressure (C) Reducing the temperature (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

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

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Description : Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in ... (A) Molal (B) Relative (C) Percentage (D) None of these

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Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

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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 case of an unsaturated mixture of gas and vapor, the percentage saturation is __________ its relative saturation. (A) Lower than (B) Higher than (C) Equal to (D) Either (A) or (B), depends on the mixture composition

Last Answer : (A) Lower than

Description : Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point

Last Answer : Option A

Description : Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of ... Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

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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

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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

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Description : _________ is the temperature to which the air must be cooled, at constant pressure, to produce saturation.  a. relative humidity  b. triple point temperature  c. dew point  d. critical point

Last Answer : dew point

Description : For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because (A) Water has a high latent heat of evaporation (B) Lewis number is close to unity (C) They are always equal under all circumstances

Last Answer : (A) Water has a high latent heat of evaporation

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Description : Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and (A) ... temperature decreasing B) Humidified at constant wet bulb temperature (C) Dehumidified (D) None of these

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Description : Dry-bulb temperature is: a. The absolute temperature corresponding to the atmospheric pressure b. The same as the wet-bulb temperature if the relative humidity is less than 100% c. Not required ... d. The temperature of the air measured with an ordinary thermometer e. The dew point temperature

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Description : The relative saturation of an unsaturated mixture of gas and vapor is independent of the (A) Nature of the vapor (B) Temperature of the mixture (C) Composition of the mixture (D) None of these

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Description : The term "approach" in a cooling tower refers to the difference in the temperature of the (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B ... (C) Hot water entering and the cooled water leaving the cooling tower (D) None of these

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Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

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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)

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Description : Pick out the wrong statement. (A) Constant pressure distillation cannot separate an Azeotropic mixture (B) Relative volatility of a binary mixture changes appreciably with the minor change in ... unity (D) Flash distillation is practised on wide spread scale in petroleum refinery

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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'

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Description : The term "cooling range" in a cooling tower refers to the difference in the temperature of (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B) Hot water entering the ... air (C) Hot water entering the tower and the cooled water leaving the tower (D) None of these

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Description : Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be (A) Cooled (B) Humidified (C) Both (A) & (B) (D) Dehumidified

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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 : The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature. (A) Dew point (B) Wet bulb (C) Dry bulb (D) None of these

Last Answer : (D) None of these

Description : The cooling effect in a cooling tower can be speeded up by (A) Increasing the air velocity and area of exposed wet surface (B) Reducing the barometric pressure (C) Reducing the humidity of the air (D) All (A), (B) and (C)

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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

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Description : Which of the following statement is true? A. the chart is plotted for pressure equal to 760mm Hg B. the constant wbt line represents adiabatic saturation process C. the constant wbt line coincides with constant enthalpy line D. all of the mentioned

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Description : The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb

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