Molecular Diffusion MCQs : This section focuses on the "Molecular Diffusion". These Multiple Choice Questions (MCQs) should be practiced to improve the Molecular Diffusion skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
Molecular diffusion is which type of motion?
A. Thermal motion
B. Linear motion
C. Non- turbulent motion
D. Rectilinear motion
Question 2
Refer to Q4, and calculate the diffusivity of O2 in a gas mixture.
A. 1.539×10-5 m2/sec
B. 1.639×10-5 m2/sec
C. 1.530×10-5 m2/sec
D. 1.630×10-5 m2/sec
Question 3
What id D ab called in the Fick’s law?
A. Thermal conductivity
B. Density coefficient
C. Diffusivity
D. Electrical conductivity
Question 4
What is Fick’s law applicable to?
A. Momentum transfer
B. Heat transfer
C. Mass transfer
D. Velocity transfer
Question 5
When is fick’s law applied?
A. For passive diffusion down the concentration gradient
B. Passive osmosis along concentration gradient
C. Active osmosis along concentration gradient
D. Active and passive movement of molecule along concentration gradient
Question 6
Which diffusion occurs when turbulent motion is there?
A. Molar diffusion
B. Eddy diffusion
C. Charge diffusion
D. No diffusion
Question 7
Which of the following formulae is right about molar flux?
A. N a = x A N – D ab (dx a /d z )
B. N a = x A N – (dx a /d z )
C. N a = x A N – cD ab
D. N a = x A N – cD ab (dx a /d z )
Question 8
Which of the following is correct representation of Fick’s law of diffusion?
A. J z = -D*dc a /dz
B. J z = -D*dT/ds
C. J z = D*dc a /dz
D. J z = -D*c a /dz
Question 9
Which of the following is FALSE about unimolar diffusion?
A. N b = N a
B. N= N a
C. N a = x a N a – cD ab (dx a /dz)
D. X b N a = cD ba (dx b /dz)
Question 10
Which of the following is Fourier law of heat conduction?
A. q z = k*dT z/dZ
B. q z = – k*dT z /dZ
C. q z = k*T z /dZ
D. q z = k*dQ z /dZ
Question 11
Which of the following is TRUE?
A. Mass transfer in ordinary mixture occurs due to temperature gradient
B. Mass transfer is proportional to the area the molecules travel
C. Net transfer stops when concentrations are equal
D. The mass transfer is proportional to the area normal to the direction of mass transfer.
Question 12
Which of the following is untrue about equimolar diffusion?
A. N a + N b =0
B. J a = J b
C. N=0
D. N a = -cD BA (dx b /dz)
Question 13
Why does the diffusion of A with respect to B occur?
A. Due to concentration gradient
B. To to volume gradient
C. Due to velocity gradiet
D. Due to change in heat