PHA 317 Exam 2 Questions WITH
Answers 100% Pass
The flow property of blood can be defined by: - CORRECT ANSWER-
viscoelasticity
Which of the following flow patterns exhibited by a drug-dosage form is extremely
unacceptable? - CORRECT ANSWER-Dilatant
Thixotropy is a special characteristic flow that is exhibited by shear thinning
systems, such as:
1. Dilatant
2. Plastic
3. Pseudoplastic - CORRECT ANSWER-Only 2 and 3 are correct
(T/F) Concentrated suspensions generally exhibit non-Newtonian flow -
CORRECT ANSWER-True
A plastic material has a yield value of 3000 dynes cm^-2. At shearing stress above
the yield value, F, was found to increase linearly with rate of shear, G. If the rate of
,shear, G, was 150 sec^-1 when F was 6000 dynes cm^-2, calculate the plastic
viscosity? - CORRECT ANSWER-20 p
The amount of force per unit area that is applied to a liquid or semi-solid is called:
- CORRECT ANSWER-shearing stress
Under which situation will the viscosity of the oil increase? - CORRECT
ANSWER-as temperature decreases
Which of the following is the most desirable flow characteristic for a dosage form
design? - CORRECT ANSWER-Thixotropic flow
(T/F) Blood plasma normally slows viscosity only, while whole blood is both
viscous and elastic - CORRECT ANSWER-True
For Newtonian fluids, if the rate of shear is increased two times from its original
value while the viscosity remains constant, what change could you expect in
shearing stress of that liquid? - CORRECT ANSWER-doubled its original value
The Arrhenius equation of rheology expresses the relationship between: -
CORRECT ANSWER-viscosity and temperature
Ostwald viscometer: - CORRECT ANSWER-is used for liquids that flow relatively
easily
(T/F) Pseudoplastic flow has yield value - CORRECT ANSWER-False
(T/F) Thixotropy is a comparatively fast recovery of a material of a consistency
lost due to shearing stress - CORRECT ANSWER-False
, A matter that exhibits plastic flow below its yield value would behave as -
CORRECT ANSWER-elastic solid
(T/F) Cup and Bob type of viscometer may be used for gels and pastes -
CORRECT ANSWER-True
Plastic flow is associated with: - CORRECT ANSWER-suspensions
Which one of the following facts is/are correct with respect to thixotropy:
i. Thixotropy is exhibited by shear thinning systems, such as pseudoplastic and
plastic liquids.
ii. Thixotropy can be defined as "an isothermal and comparatively slow recovery,
on standing of a material, of a consistency lost through shearing."
iii. Thixotropy behavior is useful for many pharmaceutical preparations e.g.,
suspensions
iv. Thixotropic system becomes more viscous upon application of shear. -
CORRECT ANSWER-Only i, ii, and iii are correct
(T/F) The viscoelasticity of an individual's blood changes significantly as the result
of cardiopulmonary bypass surgery - CORRECT ANSWER-True
Which one of the following is the most undesirable flow characteristic for a dosage
form design? - CORRECT ANSWER-Dilatant flow
Answers 100% Pass
The flow property of blood can be defined by: - CORRECT ANSWER-
viscoelasticity
Which of the following flow patterns exhibited by a drug-dosage form is extremely
unacceptable? - CORRECT ANSWER-Dilatant
Thixotropy is a special characteristic flow that is exhibited by shear thinning
systems, such as:
1. Dilatant
2. Plastic
3. Pseudoplastic - CORRECT ANSWER-Only 2 and 3 are correct
(T/F) Concentrated suspensions generally exhibit non-Newtonian flow -
CORRECT ANSWER-True
A plastic material has a yield value of 3000 dynes cm^-2. At shearing stress above
the yield value, F, was found to increase linearly with rate of shear, G. If the rate of
,shear, G, was 150 sec^-1 when F was 6000 dynes cm^-2, calculate the plastic
viscosity? - CORRECT ANSWER-20 p
The amount of force per unit area that is applied to a liquid or semi-solid is called:
- CORRECT ANSWER-shearing stress
Under which situation will the viscosity of the oil increase? - CORRECT
ANSWER-as temperature decreases
Which of the following is the most desirable flow characteristic for a dosage form
design? - CORRECT ANSWER-Thixotropic flow
(T/F) Blood plasma normally slows viscosity only, while whole blood is both
viscous and elastic - CORRECT ANSWER-True
For Newtonian fluids, if the rate of shear is increased two times from its original
value while the viscosity remains constant, what change could you expect in
shearing stress of that liquid? - CORRECT ANSWER-doubled its original value
The Arrhenius equation of rheology expresses the relationship between: -
CORRECT ANSWER-viscosity and temperature
Ostwald viscometer: - CORRECT ANSWER-is used for liquids that flow relatively
easily
(T/F) Pseudoplastic flow has yield value - CORRECT ANSWER-False
(T/F) Thixotropy is a comparatively fast recovery of a material of a consistency
lost due to shearing stress - CORRECT ANSWER-False
, A matter that exhibits plastic flow below its yield value would behave as -
CORRECT ANSWER-elastic solid
(T/F) Cup and Bob type of viscometer may be used for gels and pastes -
CORRECT ANSWER-True
Plastic flow is associated with: - CORRECT ANSWER-suspensions
Which one of the following facts is/are correct with respect to thixotropy:
i. Thixotropy is exhibited by shear thinning systems, such as pseudoplastic and
plastic liquids.
ii. Thixotropy can be defined as "an isothermal and comparatively slow recovery,
on standing of a material, of a consistency lost through shearing."
iii. Thixotropy behavior is useful for many pharmaceutical preparations e.g.,
suspensions
iv. Thixotropic system becomes more viscous upon application of shear. -
CORRECT ANSWER-Only i, ii, and iii are correct
(T/F) The viscoelasticity of an individual's blood changes significantly as the result
of cardiopulmonary bypass surgery - CORRECT ANSWER-True
Which one of the following is the most undesirable flow characteristic for a dosage
form design? - CORRECT ANSWER-Dilatant flow
