Questions and answers for exam Preparation

MCQs

Total Questions : 99 | Page 6 of 10 pages

Question 51. Filamentous fungal cells are more shear sensitive than bacterial cells because of

the presence of citin in cell walls of filamentous fungi
larger in size than bacterial cells and therefore are more susceptible to shear forces
fungal cells are much larger than bacterial cells
all of the above

Discuss Question

Answer: Option D. -> all of the above

Question 52. Non-linear relationship between shear stress and shear rate exists in

newtonian fluids
non-newtonian fluids
both (a) and (b)
none of these

Discuss Question

Answer: Option B. -> non-newtonian fluids

Question 53. A fluid in which the viscosity decreases with increasing stirrer speed and mixing time, can be represented as

newtonian fluid
pseudoplastic, thixotropic fluid
dilatant, rheopectic fluid
dilatant, pseudoplastic fluid

Discuss Question

Answer: Option B. -> pseudoplastic, thixotropic fluid

Question 54. The viscosity of water at STP is approximately

0.005 kg.m-1.s-1
0.001 kg.m-1.s-1
0.003 kg.m-2.s-1
0.1 g.cm-1.s-1

Discuss Question

Answer: Option B. -> 0.001 kg.m-1.s-1

Question 55. If the viscosity of a fluid decreases with increasing stirrer speed, then the nature of the fluid is

newtonian
pseudoplastic
dilatant
thixotropic

Discuss Question

Answer: Option B. -> pseudoplastic

Question 56. . Mixing in stirred tank reactors can

be described as either laminar, transient or turbulent
achieve turbulent conditions by increasing the stirrer speed
induce laminar flow conditions by the addition of baffles
all of the above

Discuss Question

Answer: Option A. -> be described as either laminar, transient or turbulent

Question 57. . A viscoelastic fluid is one in which the viscosity

is constant regardless of the stirrer speed or mixing time
changes during mixing but returns to its original state after mixing
increases with increasing stirrer speed
decreases with increasing stirrer speed

Discuss Question

Answer: Option B. -> changes during mixing but returns to its original state after mixing

Question 58. . The viscosity of a fluid changes with either stirrer speed or mixing time. But when mixing ceases, the viscosity returns to its original state. This fluid is best described as