Separation Processes Questions and Answers – Mass Transfer in Laminar Flow

«
»

This set of Separation Processes Multiple Choice Questions & Answers (MCQs) focuses on “Mass Transfer in Laminar Flow”.

1. The equation of motion for the liquid film in fully developed laminar flow in y-direction is:
a) µd2uy/dx2 + ρg =0
b) µd2uy/dy2 + ρg =0
c) µd2uy/dz2 + ρg =0
d) µd2uy/dx2 = 0
View Answer

Answer: c
Explanation: Flow is in y direction but changes with respect to z-direction.
Hence the equation of motion is µd2uy/dz2 + ρg =0.
advertisement

2. Which two forces is the reynold’s number a ratio of?
a) Gravitational force and interfacial force
b) Interfacial force and viscous force
c) Thermal conductivity and electrical conductivity
d) Conduction and convection
View Answer

Answer: b
Explanation: The reynold’s number Nre = 4τ/µ is the ratio of interfacial and viscous force.

3. What value of Reynold’s number is obtained with water?
a) 8
b) 16
c) 25
d) 50
View Answer

Answer: c
Explanation: The value of 25 is obtained with water.

4. What value of reynold’s number represents a laminar flow?
a) 3
b) 2500
c) 5000
d) 78
View Answer

Answer: d
Explanation: Only the value of 78 lies between 8 and 1200. SO it represents a laminar flow.

5. Which of the following is correct about Reynold’s number?
a) 3less thanNreless than1200
b) 3less thanreless than1600
c) 25less thanreless than1200
d) 8less thanreless than1200
View Answer

Answer: d
Explanation: 8less thanreless than1200 are the correct boundary conditions for Reynold’s number.
advertisement

6. Prandtl’s number is the ratio of which two quantities?
a) Momentum conductivity and thermal conductivity
b) Coefficient of convection to thermal conductivity
c) Momentum diffusivity and thermal diffusivity
d) Interfacial force and viscous force
View Answer

Answer: c
Explanation: Prandtl’s number is the ratio of Momentum diffusivity and thermal diffusivity.

7. Which of the following is true about prandtl’s number?
a) Npr = Cpµ/k
b) Npr = Cpk/µ
c) Npr = Cvµ/k
d) Npr = Cpµ
View Answer

Answer: a
Explanation: Prandtl’s number is the ratio of Momentum diffusivity and thermal diffusivity. Hence the formula is Npr = Cpµ/k.

8. What is the physical significance of nusselt’s number?
a) Ratio of convective heat transfer to conductive heat transfer
b) Ratio of convective heat transfer to conductive heat transfer
c) Ratio of total heat transfer to conductive heat transfer
d) Ratio of total transfer to convective heat transfer
View Answer

Answer: c
Explanation: Nusselt number is the Ratio of convective heat transfer to conductive heat transfer.

9. What is the correct formula for nusselt’s number?
a) hµ/k
b) hρ/k
c) hL/k
d) hΔTL/k
View Answer

Answer: c
Explanation: The nusselt number hL/k is the ratio of total heat transfer to onductive heat transfer.
advertisement

10. Which of the following is most true?
a) Na = kcA(cai – ca)
b) Na = kcAΔc
c) Na = kcA(cai – ca)mean
d) Na = kcA(cai – ca)log mean
View Answer

Answer: b
Explanation: Δc is taken as the driving force and is true every time. It’s expression will change depending upon the conditions.

Sanfoundry Global Education & Learning Series – Separation Processes.

To practice all areas of Separation Processes, here is complete set of 1000+ Multiple Choice Questions and Answers.

Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

advertisement
advertisement
advertisement
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn