Mass Transfer and Diffusion

This is an MCQ-based quiz on the topic of Mass Transfer and Diffusion.

This includes the following topics:-

Steady-state, Ordinary Molecular Diffusion
Steady and Unsteady State Mass Transfer Through Stationary Media
Mass Transfer in Laminar Flow
Mass Transfer in Turbulent Flow
Two Film Theory and Overall Mass Transfer Coefficients

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Which of the following is most true?

Na = kcA(cai – ca) Na = kcAΔc Na = kcA(cai – ca)mean Na = kcA(cai – ca)log mean

What is the correct formula for nusselt’s number?

hµ/k hρ/k hL/k hΔTL/k

What is the physical significance of nusselt’s number?

Ratio of convective heat transfer to conductive heat transfer Ratio of convective heat transfer to conductive heat transfer Ratio of total heat transfer to conductive heat transfer Ratio of total transfer to convective heat transfer

Which of the following is true about prandtl’s number?

Npr = Cpµ/k Npr = Cpk/µ Npr = Cvµ/k Npr = Cpµ

Prandtl’s number is the ratio of which two quantities?

Momentum conductivity and thermal conductivity Coefficient of convection to thermal conductivity Momentum diffusivity and thermal diffusivity Interfacial force and viscous force

The equation of motion for the liquid film in fully developed laminar flow in y-direction is:

µd2uy/dx2 + ρg =0 µd2uy/dy2 + ρg =0 µd2uy/dz2 + ρg =0 µd2uy/dx2 = 0

Which two forces is the reynold’s number a ratio of?

Gravitational force and interfacial force Interfacial force and viscous force Thermal conductivity and electrical conductivity Conduction and convection

What value of Reynold’s number is obtained with water?

8 16 25 50

What value of reynold’s number represents a laminar flow?

3 2500 5000 78

Which of the following reynold’s number represents a turbulent flow?

500 700 2500 6000

Which of the following is present in turbulent flow mass transfer?

Slow mass transfer Less mass transfer Eddy currents Eddy diffusion

What is the physical significance of drag coefficient?

It is drag force divided by projected area and velocity head It is the ratio of pipe wall shear stress and velocity head It is the ratio of inertial forces to viscous force It is the ratio of inertial force to surface tension force

What is the physical significance of weber number?

What is the physical significance of lewis number?

It is the ratio of bulk transfer mass and molecular diffusion It is the ratio of thermal diffusivity to mass diffusivity It is the ratio of conductive mass transfer to molecular diffusion It is the ratio of mass transfer to mass capacity

Which of the following is correct about Reynold’s number?

3 less than re less than 1200

3 less than re less than 1600

25 less than re less than 1200

8 less than re less than 1200

Quiz/Test Summary

Title: Mass Transfer and Diffusion

Questions: 15

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