Question

A pseudoplastic fluid is best characterized by

• A. Increase in apparent viscosity as the shear rate increases
• B. Decrease in apparent viscosity as the shear rate increases
• C. The structure breaks down and apparent viscosity decreases with continuous shear stress
• D. The structure builds up and apparent viscosity decreases with continuous shear stress

Hint:

Pseudoplastic = Shear thinning Examples: Paint, ketchup, blood — they flow more easily when stirred or shaken.

Answer 1

The Correct Option is B

Concept: A pseudoplastic fluid is a type of non-Newtonian fluid that exhibits shear-thinning behavior. This means its apparent viscosity decreases as the shear rate increases.

Step 1: Understand pseudoplastic behavior.
In pseudoplastic fluids:
• Viscosity decreases with increasing shear rate
• Fluid flows more easily when stirred or stressed

Step 2: Analyze the options.

• Increase in viscosity → shear-thickening (not correct)
• Decrease in viscosity with shear rate → correct
• Structure breakdown over time → thixotropic behavior
• Structure build-up → rheopectic behavior

Step 3: Final conclusion.
Thus, a pseudoplastic fluid is characterized by: \[ Decrease in apparent viscosity as the shear rate increases \]