Statement 1: Penetration theory states that mass transfer coefficient is directly proportional to diffusivity coefficient which was later proved wrong. Statement 2: Penetration theory states that mass transfer is based on unsteady mass transfer.

Consider the following statements: 1. If x is directly proportional to z and y is directly proportional to z, then (x2 - y2) is directly proportional to z2. 2. If x is inversely proportional to z and y is inversely proportional to z, then (xy) is inversely proportional to z2. Which of the above statements is/are correct?

A

1 only

B

2 only

C

Both 1 and 2

D

Neither 1 nor 2

How is the degree of emulsion polymerization related to the monomer concentration, and the rate of radical generation, Ri? , inversely proportional to Ri b) inversely proportional to Ri, directly proportional to . c) directly proportional to Ri, independent of . d) directly proportional to , independent of Ri

A

and the rate of radical generation, Ri? ] directly proportional to , inversely proportional to Ri

B

M

C

M

D

M

Consider the following statement for a ball falling in a viscous fluid: a) The viscous force is directly proportional to the radius of the ball b) The viscous force is directly proportional to the velocity of the ball c) The viscous force is inversely proportional to the radius of the ball d) The viscous force is inversely proportional to the velocity of the ball Which of the above statements are correct?

A

Both a and b are correct

B

Both a and d are correct

C

Both b and c are correct

D

Both c and d are correct

Statement 1: In film theory, mass transfer coefficient is proportional to D1/2 Statement 2: Penetration theory states that all elements are exposed at the same time which is unrealistic.

A

True, False

B

True, True

C

False, False

D

False, True

A stream of air at 100 kPa pressure and 300 K is flowing on the top surface of a thin flat sheet of solid naphthalene of length 0.2 m with a velocity of 20 m/sec. The other data are: Mass diffusivity of naphthalene vapor in air = 6 * 10 –6 m2/sec Kinematic viscosity of air = 1.5 * 10 –5 m2.sc Concentration of naphthalene at the air-solid naphthalene interface = 1 * 10 – 5 kmol/m3 Calculate the overage mass transfer coefficient over the flat plate. Note: For heat transfer over a flat plate, convective heat transfer coefficient for laminar flow can be calculated by the equation. Nu = 0.664 ReL1/2 Pr1/3 you may use analogy between mass and heat transfer.

A

0.014 m/sec

B

0.015 m/sec

C

0.016 m/sec

D

0.013 m/sec

Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and 't' is time)

A

(De.t)1/2

B

(De/t)1/2

C

(4De/πt)1/2

D

(4De/t)

Penetration theory states that the mass transfer co-coefficient is equal to (where, D_e is diffusivity and 't' is time)

A

$${\left( {{{\text{D}}_{\text{e}}}.{\text{t}}} \right)^{\frac{1}{2}}}$$

B

$${\left( {\frac{{{{\text{D}}_{\text{e}}}}}{{\text{t}}}} \right)^{\frac{1}{2}}}$$

C

$${\left( {\frac{{4{{\text{D}}_{\text{e}}}}}{{\pi {\text{t}}}}} \right)^{\frac{1}{2}}}$$

D

$$\frac{{4{{\text{D}}_{\text{e}}}}}{{\text{t}}}$$

The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = __________

A

1

B

0.5

C

10

D

0

The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, N_Pr = N_Sc = __________

A

1

B

0.5

C

10

D

0

Statement 1: Unsteady state heat transfer equation can be used when there is negligible internal resistance. Statement 2: Unsteady state heat transfer equation can be used for liquid food items which are well stirred, because, temperature gradient within won’t be there.

A

True, False

B

True, True

C

False, False

D

False, True

Statement 1: Penetration theory states that mass transfer coefficient is directly proportional to diffusivity coefficient which was later proved wrong. Statement 2: Penetration theory states that mass transfer is based on unsteady mass transfer.

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