Project ForgeWhich of the following statements are CORRECT? P. For a rheopectic fluid, the apparent viscosity increases with time under a constant applied shear stress. Q. For a pseudoplastic fluid, the apparent viscosity decreases with time under a constant applied shear stress. R. For a Bingham plastic, the apparent viscosity increases exponentially with the deformation rate. S. For a dilatant fluid, the apparent viscosity increases with increasing deformation rate.
- AP and Q only
- BQ and R only
- CR and S only
- P and S only
Explanation
P is correct: rheopectic behavior is defined as apparent viscosity increasing with TIME under constant shear. Q is wrong: pseudoplastic (shear-thinning) behavior depends on shear RATE, not time. R is wrong: an ideal Bingham plastic has constant viscosity above the yield stress, not an exponential increase. S is correct: dilatant (shear-thickening) fluids show apparent viscosity increasing with deformation (shear) rate. So P and S only.
Source: GATE CH 2014 (2014)
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