Humidification is the process of addition moisture in air at A. constant wet bulb temperature B. constant dry bulb temperature C. constant latent heat D. none of the above  

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ANSWER  : B

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Description : Wet-bulb temperature is: a. The temperature indicated by a thermometer whose bulb covered by a water-wetted wick and exposed to a rapidly moving stream of air b. The same as the dry-bulb ... point temperature d. Always less than the dry-bulb temperature e. Not required to find the relative humidity

Last Answer : Answer: A

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

Last Answer : Answer: D

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 : The temperature of air recorded by thermometer when the bulb is covered by a cotton wick saturated by water is called as A. dry bulb temperature B. wet bulb temperature C. stream temperature D. psychrometric temperature

Last Answer : ANSWER : B

Description : When, H1 = Total heat of air entering the coil (heating or cooling) H2 = Total heat of air leaving the coil (heating or cooling) H3 = Total heat of air at the end of ... A. cooling and humidification B. cooling and dehumidification C. heating and humidification D. heating and dehumidification

Last Answer : ANSWER : 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

Last Answer : (C) Both heating and humidification

Description : Sling psychrometer is used to measure A. only dry bulb temperature B. only wet bulb temperature C. dry and wet bulb temperature D. relative humidity

Last Answer : ANSWER : C

Description : At any point on the saturation curve in psychometric chart, the dry bulb temperature is always A. less than the corresponding wet bulb temperature B. more than the corresponding wet bulb temperature C. equal to the corresponding wet bulb temperature D. cannot predict

Last Answer : ANSWER : C

Description : When dry bulb temperature (DBT) and wet bulb temperature (WBT) are measured, greater the difference between DBT and WBT, A. greater the amount of water vapour held in the mixture B. smaller the amount of ... the mixture C. same the amount of water vapour held in the mixture D. none of the above

Last Answer : ANSWER : B

Description : Which temperature can be measured by an instrument called psychrometer? A. dry bulb temperature B. wet bulb temperature C. both a. and b. D. none of the above

Last Answer : ANSWER : C

Description : In sensible heating or cooling, A. work done remains constant B. dry bulb temperature or air remains constant C. both of the mentioned D. none of the mentioned

Last Answer : ANSWER : A

Description : The temperature at which the air cannot hold all the water vapour mixed in it and some vapour starts condensing is called as A. humidification temperature B. dehumidification temperature C. dew point temperature D. none of the above

Last Answer : ANSWER : C

Description : The dew point temperature is less than the wet bulb temperature for A. saturated air B. unsaturated air C. both saturated and unsaturated air D. none of the above

Last Answer : ANSWER : B

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

Description : n a chemical factory where dyes are made, wet cake at 30 OC consisting of 60% moisture  is put in a dryer to obtain an output having only 5% moisture, at atmospheric pressure. In  each batch about 120 ... dryer and the dryer efficiency  is 80%. Latent heat of steam at 4 kg/cm2 is 520 kcal/kg.

Last Answer : Given that   Qty of material dried per batch - 120 Kgs  Moisture at inlet - 60% a. The quantity of moisture removed per batch.  Water quantity in a wet batch - 120 x 0.6 = 72 Kgs.  Quantity of bone dry ... - 48/0.95 = 50.5 Kgs.  Equivalent water in a dry batch - 50.5 - 48 = 2.5 Kgs.

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

Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column

Description : The horizontal line in psychrometric chart joining the change of state of air represents A. humidification B. sensible cooling or heating C. sensible cooling or heating with humidification D. sensible cooling or heating with dehumidification

Last Answer : ANSWER : B

Description : Heating and humidification is done in A. summer air conditioning B. winter air conditioning C. both of the mentioned D. none of the mentioned

Last Answer : ANSWER : B

Description : The dew point is the: a. Dry bulb temperature on a psychrometer b. Temperature at which water vapour will start to be absorbed into the air c. Temperature below which water vapour will start to ... vapour will start to condense out of the air e. Temperature at which water will start to evaporate

Last Answer : Answer: C

Description : At 100% relative humidity, the wet bulb temperature is A. lower than the dew point temperature B. higher than the dew point temperature C. equal to the dew point temperature D. none of the above

Last Answer : ANSWER : C

Description : On psychrometric chart, wet bulb temperature lines are A. horizontal with uniformly spaced B. horizontal with non-uniformly spaced C. inclined with uniformly spaced D. inclined with non-uniformly spaced

Last Answer : ANSWER :C

Description : Evaporative cooling process employs a combination of cooling and humidification in which the (A) Sensible heat is added (B) Sensible heat is removed and the latent heat is added (C) Latent heat is removed (D) Sensible heat is added and latent heat is removed

Last Answer : Option B

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 : When air passes through silica gel, A. it absorbs water vapour molecules B. latent heat of condensation is released C.dbt of air increases D. all of the mentioned

Last Answer : ANSWER : D

Description : Describe any two sources of air leak in surface condenser. Also describe effect of air leak on latent heat of steam and cooling water requirements.

Last Answer : ✓ The main sources of air leakage found in condenser are given below: 1) There is leakage of air from atmosphere at the joint of the parts which are internally under a pressure less ... hence evaporation enthalpy of steam increases therefore more amount of cooling water required in the condenser. 

Description : What is sensible cooling of air? A. the cooling in which sensible heat of air is removed in order to reduce temperature B. the cooling in which temperature of air is reduced without changing in its moisture content C. both a. and b. D. none of the above

Last Answer : ANSWER : C

Description : Choose the correct statement (a) A refrigerant should have low latent heat (b) If operating temperature of system is low, then refrigerant with low boiling point should be used (c) Pre-cooling and sub-cooling bf refrigerant are same (d) Superheat and sensible heat of a. refrigerant are same

Last Answer : Ans: b

Description : Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned

Last Answer : Answer: c Explanation: None.

Description : The dry-bulb temperature scale is read on a psychrometric chart along the: a. Left vertical axis b. Right vertical axis c. Saturation line and sloping downward to the right d. Top horizontal axis e. Horizontal axis on the bottom of the chart

Last Answer : ANSWER : E

Description : In a constant pressure process steam is generated from 10 bar and 0.8 dry condition till it become dry and saturated. Determine amount of heat added per kg of steam. From steam table at 10 bar Tsat = 179.9°C hf = 762.6 kl/kg, hg = 2776.2 kJ/kg 

Last Answer : Constant pressure process Final condition of steam is dry saturated Enthalpy of dry steam = hg= hf + hfg =2776.2 KJ/Kg .Given Latent heat of vaporization = hfg = hg - hf =2776.2-762.6 =2013.6 KJ/Kg Initial condition ... hfg = 762.6+0.8 X 2013.6 =2373.48 KJ/Kg Heat added = hg-hw = 402.72 KJ/kg

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

Last Answer : (A) Humidified with wet bulb temperature decreasing

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 : 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 : 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

Last Answer : (D) Dew point temperature

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 process (A) Wet bulb temperature increases (B) Dry bulb temperature remains constant (C) Dew point temperature increases (D) Dry bulb temperature increases

Last Answer : Option B

Description : An indication of sensible heat content in air-water vapour mixture is a) wet bulb temperature b) dew point temperature c) density of air d) dry bulb temperature

Last Answer : d) dry bulb temperature

Description : Which of the following is not a desirable property of a refrigerant (a) highmisibility with oil (b) low boiling point (c) good electrical conductor (d) large latent heat

Last Answer : Ans: c

Description : At lower temperatures and pressures, the latent heat of vaporization of a refrigerant (a) decreases (b) increases (c) remains same (d) depends on other factors

Last Answer : Ans: b

Description : The refrigerant for a refrigerator should have (a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat

Last Answer : Ans: c

Description : Dew point can be best defined as the: a. Absolute temperature at which air, upon heating, will evaporate moisture b. . Percentage of moisture that air can hold at a given temperature ... to condense should the temperature drop further e. . Atmospheric pressure at which air will condense moisture

Last Answer : Answer: D

Description : The term "relative humidity" applies to a) the percentage of moisture in the air as compared to the amount of moisture the air can hold at a specific temperature b) the weight of the moisture in the air c) ... of the air d) the amount of moisture in the air e) the amount of humidity in the air

Last Answer : ANSWER : A

Description : Absolute or specific humidity is a) the actual mass of moisture present in a specific amount of air b) the maximum mass of moisture that a specific amount of air can hold c) the ratio of ... a specific amount of air at that absolute temperature e) a specific amount of air saturated with moisture

Last Answer : ANSWER : A

Description : Dew point temperature always gives an indication of the __________ of the moist air. (A) Dryness (B) Moisture content (C) Coolness (D) Latent heat

Last Answer : (B) Moisture content

Description : The condition of refrigerant before entering the expansion or throttle valve, in a vapour compression system (a) dry vapour (b) wet vapour (c)liquid-vapour mixture (d) high pressure saturated liquid

Last Answer : Ans: d

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

Last Answer : (A) Dew point

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 : Which of the following parameters remains constant during chemical dehumidification? (A) Dry bulb temperature (B) Partial pressure of vapour (C) Wet bulb temperature (D) None of these

Last Answer : (A) Dry bulb temperature