What is the value of m1 / m2 if W1 = 0.0157 kg/ kg of dry air, W2 = 0.0084 kg / kg of dry air and W3 = 0.0103 kJ/ kg of dry air?

In a laboratory test run, the rate of drying was found to be 0.5 × 10^-3 kg/m².s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m²/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is

A

2000

B

4000

C

5000

D

6000

What is the value of Latent heat transfer in a process of humidification having hfg = 10 kJ / kg of dry air, W1 = 0.0071 kJ / kg of dry air and W2 = 0.0017 kJ / kg of dry air?

A

0.054

B

0.0054

C

0.54

D

5.4

What is the value of m1 / m2 if h1 = 81 kJ/ kg of dry air, h2 = 46 kJ/ kg of dry air and h3 = 58 kJ/ kg of dry air?

A

1

B

0

C

0.51

D

0.52

The bypass factor (B. P. F.) in case of sensible heating of air is (Where td₁ = Dry bulb temperature of air entering the heating coil, td₂ = Dry bulb temperature of air leaving the heating coil, and td₃ = Dry bulb temperature of heating coil)

A

(td₂ - td₃)/(td₃ - td₁)

B

(td₃ - td₂)/(td₃ - td₁)

C

(td₃ - td₁)/(td₂ - td₃)

D

(td₃ - td₁)/(td₃ - td₂)

The bypass factor, in case of sensible cooling of air, is given by (where td₁ = Dry bulb temperature of air entering the cooling coil, td₂ = Dry bulb temperature of air leaving the cooling coil, and td₃ = Dry bulb temperature of the cooling coil)

A

(td₁ -td₃)/( td₂ -td₃)

B

(td₂ -td₃)/( td₁ -td₃)

C

(td₃ -td₁)/( td₂ -td₃)

D

(td₃ -td₂)/( td₁ -td₃)

The bypass factor (B.P.F.) in case of sensible heating of air is (Where td₁ = Dry bulb temperature of air entering the heating coil, td₂ = Dry bulb temperature of air leaving the heating coil and td₃ = Dry bulb temperature of heating coil)

A

$$\frac{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$

B

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$

C

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

D

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}$$

The bypass factor, in case of sensible cooling of air, is given by (where td₁ = Dry bulb temperature of air entering the cooling coil, td₂ = Dry bulb temperature of air leaving the cooling coil and td₃ = Dry bulb temperature of the cooling coil)

A

$$\frac{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

B

$$\frac{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}$$

C

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

D

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}$$

At equilibrium the concentration of water in vapour phase (C^*) in kg/m³ of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C^* = 0.0667 m. To maintain dry conditions in a room of air space 100 m³ containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is

A

0.0

B

0.2

C

0.4

D

1.0

Student A rub solid baking soda on dry litmus paper, B rub metal oxide on dry litmus paper, C dip litmus paper in vinegar, D dip litmus paper in aqueous solution of baking soda. The observations were made by student A, B, C, and D should be- Student Effect on dry red litmus paper Effect on dry blue litmus paper A Color Changed to blue No change B No change Color changed to red C No change Color changed to red D Color Changed to blue Color changed to red The correct observation was made by the student

A

B

C

D

200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, N_c = 0.5 × 10^-3 kg/m².s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m²/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)

A

0.5

B

0.05

C

0.1

D

0.15

What is the value of m1 / m2 if W1 = 0.0157 kg/ kg of dry air, W2 = 0.0084 kg / kg of dry air and W3 = 0.0103 kJ/ kg of dry air?

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