Pick out the wrong statement

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Pick out the wrong statement.

A. The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonion fluids is $$\frac{{\text{D}}}{{4{\text{L}}}} \cdot \Delta {\text{p}}$$

B. In the equation, $$\tau \cdot {{\text{g}}_{\text{c}}} = {\text{k}} \cdot {\left( {\frac{{{\text{du}}}}{{{\text{dy}}}}} \right)^{\text{n}}}$$ the value of the value of 'n' for pseudoplastic and dilatant fluids are < 1 and > 1 respectively.

C. Shear stress for Newtonion fluid is proportional to the rate of shear in the direction perpendicular to motion

D. With increase in the Mach number > 0.6, the drag co-efficient decreases in case of compressible fluids

Answer: Option D

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