The critical moisture content in case of drying indicates the __________ rate period. (A) Beginning of falling (B) Beginning of constant (C) End of falling (D) None of these

The critical moisture content in case of drying indicates the __________

rate period.

(A) Beginning of falling

(B) Beginning of constant

(C) End of falling

(D) None of these

by

1 Answer

Answer :

(A) Beginning of falling

by

Related questions

Pick out the correct statement. (A) Bound moisture is removed during constant rate drying period (B) Free moisture is removed during falling rate drying period (C) The sum of free moisture and equilibrium moisture in a solid is called the critical moisture (D) The driving force for mass transfer in a wet solid is its free moisture content

Description : Pick out the correct statement. (A) Bound moisture is removed during constant rate drying period (B) Free moisture is removed during falling rate drying period (C) The sum of free moisture and ... (D) The driving force for mass transfer in a wet solid is its free moisture content

Last Answer : (D) The driving force for mass transfer in a wet solid is its free moisture content

The drying time between fixed moisture content within diffusion controlled 'falling rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid). (A) √T (B) T (C) T 2 (D) T

Description : The drying time between fixed moisture content within diffusion controlled 'falling rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid). (A) √T (B) T (C) T 2 (D) T

Last Answer : (C) T

During drying of a solid, the critical moisture content increases with (A) Decreased drying rate (B) Increased thickness of the solid (C) Increased drying rate (D) Both (B) and (C)

Description : During drying of a solid, the critical moisture content increases with (A) Decreased drying rate (B) Increased thickness of the solid (C) Increased drying rate (D) Both (B) and (C)

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

Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to Nusselt number in heat transfer and Schmidt number to Prandtl number (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger (D) Hot gases at moderate pressure are usually in the shell side of shell and tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger

It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The equilibrium moisture content of the solid is 5%). (A) 15 min (B) 51 min (C) 71 min (D) 94 min

Description : It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The ... 5%). (A) 15 min (B) 51 min (C) 71 min (D) 94 min

Last Answer : (C) 71 min

The drying time between fixed moisture contents within the 'constant rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid). (A) √T (B) T (C) T 1.5 (D) T

Description : The drying time between fixed moisture contents within the 'constant rate period' is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid). (A) √T (B) T (C) T 1.5 (D) T

Last Answer : (B) T

In the constant rate period of the rate of drying curve for batch drying, (A) Cracks develop on the surface of the solid (B) Rate of drying decreases abruptly (C) Surface evaporation of unbound moisture occurs (D) None of these

Description : In the constant rate period of the rate of drying curve for batch drying, (A) Cracks develop on the surface of the solid (B) Rate of drying decreases abruptly (C) Surface evaporation of unbound moisture occurs (D) None of these

Last Answer : (C) Surface evaporation of unbound moisture occurs

During the constant rate period of drying of a solid, (A) Increased air humidity decreases the rate of drying (B) Increasing the air temperature decreases the drying rate (C) Surface evaporation of unbound moisture occurs (D) None of these

Description : During the constant rate period of drying of a solid, (A) Increased air humidity decreases the rate of drying (B) Increasing the air temperature decreases the drying rate (C) Surface evaporation of unbound moisture occurs (D) None of these

Last Answer : (C) Surface evaporation of unbound moisture occurs

Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate. (A) Increases (B) Decreases (C) Does not affect

Description : Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate. (A) Increases (B) Decreases (C) Does not affect

Last Answer : (B) Decreases

During drying operation, it is easier to remove the __________ moisture. (A) Equilibrium (B) Critical (C) Unbound (D) Bound

Description : During drying operation, it is easier to remove the __________ moisture. (A) Equilibrium (B) Critical (C) Unbound (D) Bound

Last Answer : (C) Unbound

The falling rate period in the drying of a solid is characterised by (A) Increase in rate of drying (B) Increasing temperatures both on the surface and within the solid (C) Decreasing temperatures (D) None of these

Description : The falling rate period in the drying of a solid is characterised by (A) Increase in rate of drying (B) Increasing temperatures both on the surface and within the solid (C) Decreasing temperatures (D) None of these

Last Answer : (B) Increasing temperatures both on the surface and within the solid

With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________, if the conduction and radiation through the solid are negligible. (A) Increases (B) Decreases (C) Remain same

Description : With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________, if the conduction and radiation through the solid are negligible. (A) Increases (B) Decreases (C) Remain same

Last Answer : (A) Increases

Drying operation under vacuum is carried out to (A) Dry those materials which have very high unbound moisture content (B) Reduce drying temperature (C) Increase drying temperature (D) Dry materials having high bound moisture content

Description : Drying operation under vacuum is carried out to (A) Dry those materials which have very high unbound moisture content (B) Reduce drying temperature (C) Increase drying temperature (D) Dry materials having high bound moisture content

Last Answer : (B) Reduce drying temperature

Advantage of continuous drying over batch drying is that the (A) Drying cost per unit weight of dried product is less (B) Product with more uniform moisture content is produced (C) Equipment size required is smaller (D) All 'a', 'b' & 'c'

Description : Advantage of continuous drying over batch drying is that the (A) Drying cost per unit weight of dried product is less (B) Product with more uniform moisture content is produced (C) Equipment size required is smaller (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

Mechanism of moisture removal in case of freeze drying of food stuff is by (A) Evaporation (B) Sublimation (C) Dehydration (D) Adsorption

Description : Mechanism of moisture removal in case of freeze drying of food stuff is by (A) Evaporation (B) Sublimation (C) Dehydration (D) Adsorption

Last Answer : (B) Sublimation

During constant rate period, the rate of drying decreases with the (A) Decrease in air temperature (B) Increase in air humidity (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : During constant rate period, the rate of drying decreases with the (A) Decrease in air temperature (B) Increase in air humidity (C) Both (A) and (B) (D) Neither (A) nor (B)

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

The practical limit of moisture content achieved in air drying of timber is (A) 5 % (B) 15 % (C) 25 % (D) 35

Description : The practical limit of moisture content achieved in air drying of timber is (A) 5 % (B) 15 % (C) 25 % (D) 35 %

Last Answer : Answer: Option B

Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a distillation column (C) Separation of components is not possible in liquid extraction, if selectivity is unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

Description : Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a ... unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

Last Answer : (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. (A) Unsaturated surface (B) Constant rate (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. (A) Unsaturated surface (B) Constant rate (C) Both (A) and (B) (D) Neither (A) nor (B)

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

Pick up the correct statement from the following: (A) Higher workability indicates unexpected increase in the moisture content (B) Higher workability indicates deficiency of sand (C) If the concrete mix is dry, the slump is zero (D) All the above

Description : Pick up the correct statement from the following: (A) Higher workability indicates unexpected increase in the moisture content (B) Higher workability indicates deficiency of sand (C) If the concrete mix is dry, the slump is zero (D) All the above

Last Answer : Answer: Option D

A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

Description : A thin, flat & square plate measuring 2 m 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will ... heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

Last Answer : (B) 100

Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the __________ moisture. (A) Bound (B) Unbound (C) Critical (D) None of these

Description : Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the __________ moisture. (A) Bound (B) Unbound (C) Critical (D) None of these

Last Answer : (A) Bound

Moisture contained by a substance in excess of the equilibrium moisture is called the __________ moisture. (A) Unbound (B) Free (C) Critical (D) Bound

Description : Moisture contained by a substance in excess of the equilibrium moisture is called the __________ moisture. (A) Unbound (B) Free (C) Critical (D) Bound

Last Answer : (B) Free

Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture. (A) Unbound (B) Critical (C) Free (D) Bound

Description : Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture. (A) Unbound (B) Critical (C) Free (D) Bound

Last Answer : (A) Unbound

Determination of water content of a soil sample suspected to contain gypsum is made by drying the sample for longer period at a temperature not more than (A) 60°C (B) 80°C (C) 100°C (D) 110°C

Description : Determination of water content of a soil sample suspected to contain gypsum is made by drying the sample for longer period at a temperature not more than (A) 60°C (B) 80°C (C) 100°C (D) 110°C

Last Answer : (B) 80°C

Pick out the wrong statement: (A) Change in barometric pressure does not affect the relative humidity (B) In case of a packed tower, the operating velocity is about half of the flooding velocity, generally (C) 'Elution' means the desorption of the adsorbed solute by a solvent (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

Description : Pick out the wrong statement: (A) Change in barometric pressure does not affect the relative humidity (B) In case of a packed tower, the operating velocity is about half of the ... (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

Last Answer : (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

The rate of silting in a reservoir (A) Is less in the beginning (B) Remains constant throughout (C) Is more in the beginning (D) is more in the beginning and reduces in the end

Description : The rate of silting in a reservoir  (A) Is less in the beginning  (B) Remains constant throughout  (C) Is more in the beginning  (D) is more in the beginning and reduces in the end 

Last Answer : (D) is more in the beginning and reduces in the end 

Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter(A) Filtering(B) Washing(C) Drying(D) All (A), (B) & (C).

Description : Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter. (A) Filtering (B) Washing (C) Drying (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

Description : Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

Last Answer : A) Radiation

A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process? (A) Flow rate of inlet air (B) Relative humidity of outlet air (C) Humidity of inlet air (D) Temperature of the solid

Description : A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process? (A) Flow rate of inlet air (B) Relative humidity of outlet air (C) Humidity of inlet air (D) Temperature of the solid

Last Answer : (D) Temperature of the solid

Which section is basically a sequence of instruction with a clear indication of beginning and end for updating shared variables. a. Racing section b. Critical section c. d. Both None of thes

Description : Which section is basically a sequence of instruction with a clear indication of beginning and end for updating shared variables. a. Racing section b. Critical section c. d. Both None of thes

Last Answer : . Critical sectio

Aniline point test of an oil qualitatively indicates the __________ content of an oil. (A) Paraffin (B) Olefin (C) Aromatic (D) Naphthene

Description : Aniline point test of an oil qualitatively indicates the __________ content of an oil. (A) Paraffin (B) Olefin (C) Aromatic (D) Naphthene

Last Answer : (C) Aromatic

The optimum moisture content in solids to be crushed/ground ranges from __________ percent. (A) 3 to 4 (B) 8 to 10 (C) 10 to 15 (D) 15 to 20

Description : The optimum moisture content in solids to be crushed/ground ranges from __________ percent. (A) 3 to 4 (B) 8 to 10 (C) 10 to 15 (D) 15 to 20

Last Answer : (A) 3 to 4

The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Description : The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Last Answer : (C) Ash

Moisture content of a substance when at equilibrium with a given partial pressure of the vapour is called the __________ moisture. (A) Free (B) Unbound (C) Equilibrium (D) Bound

Description : Moisture content of a substance when at equilibrium with a given partial pressure of the vapour is called the __________ moisture. (A) Free (B) Unbound (C) Equilibrium (D) Bound

Last Answer : (C) Equilibrium

Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content. (A) Rotary (B) Tray (C) Freeze (D) None of these

Description : Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content. (A) Rotary (B) Tray (C) Freeze (D) None of these

Last Answer : (B) Tray

A good coking coal should have high __________ content. (A) Ash (B) Sulphur & phosphorus (C) Moisture (D) None of these

Description : A good coking coal should have high __________ content. (A) Ash (B) Sulphur & phosphorus (C) Moisture (D) None of these

Last Answer : (D) None of these

Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen (C) Carbon, sulphur, volatile matter & ash (D) Carbon, volatile matter, ash & moisture

Description : Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen (C) Carbon, sulphur, volatile matter & ash (D) Carbon, volatile matter, ash & moisture

Last Answer : (A) Carbon, hydrogen, nitrogen & sulphur

Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture, volatile matter, ash & fixed carbon (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Description : Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture, volatile matter, ash & fixed carbon (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Last Answer : (B) Moisture, volatile matter, ash & fixed carbon

Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced. (A) Colour (B) Moisture content (C) Ash content (D) Volatile matter

Description : Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced. (A) Colour (B) Moisture content (C) Ash content (D) Volatile matter

Last Answer : (D) Volatile matter

Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture & volatile matter (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Description : Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture & volatile matter (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Last Answer : (B) Moisture & volatile matter

Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen(C) Carbon, sulphur, volatile matter & ash(D) Carbon, volatile matter, ash & moisture

Description : Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen (C) Carbon, sulphur, volatile matter & ash (D) Carbon, volatile matter, ash & moisture

Last Answer : (C) Carbon, sulphur, volatile matter & ash

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

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

The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Description : The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Last Answer : Option D

Which of the following procedures should be used to maintain a large electric motor during periods of inactivity? A. A thin layer of air-drying varnish should be applied on the windings. B. Compressed air should be blown over areas where dust is deposited. C. Spraying a solvent periodically to remove carbon dust. D. Space heaters should be used to prevent condensation of moisture.

Description : Which of the following procedures should be used to maintain a large electric motor during periods of inactivity? A. A thin layer of air-drying varnish should be applied on the windings. B. ... periodically to remove carbon dust. D. Space heaters should be used to prevent condensation of moisture.

Last Answer : Answer: D

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 kgs of material is dried. a. The quantity of moisture removed per batch. b. What is the total quantity ( sensible & latent) of heat required to evaporate the moisture, if the latent heat of water is 540 kcal/kg at atmospheric conditions, Ignore heat absorbed by the solids c. Find the quantity of steam required for the drying process (per batch), if steam at 4 kg/cm2 is used for generating hot air in the dryer and the dryer efficiency is 80%. Latent heat of steam at 4 kg/cm2 is 520 kcal/kg.

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.

The lower limit of moisture by sun drying is approximately ____ percent. a. 10 c. 20 b. 15 d. 30

Description : The lower limit of moisture by sun drying is approximately ____ percent. a. 10 c. 20 b. 15 d. 30

Last Answer : b. 15