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GATE 2022 CE (CE2) – Question 21

Fluid Mechanics · Properties of fluids, fluid statics · 1 mark · Multiple choice

The dimension of dynamic viscosity is:

  1. $ML^{-1}T^{-1}$
  2. $ML^{-1}T^{-2}$
  3. $ML^{-2}T^{-2}$
  4. $ML^0T^{-1}$

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Correct answer: (A) $ML^{-1}T^{-1}$

Explanation

Newton’s viscosity law is $\tau=\mu(du/dy)$. Stress has dimension $ML^{-1}T^{-2}$ and velocity gradient has dimension $T^{-1}$.

Their ratio gives $[\mu]=\mathbf{ML^{-1}T^{-1}}$, **A**.