Question

What is the dimension of the coefficient of viscosity $\eta$ ?

• A. $ML ^{-1} T ^{-2}$
• B. $MLT^{- 1}$
• C. $ML^{- 1}T^{- 1}$
• D. $ML^{- 2}T^{- 2}$

Answer 1

Answer: (C)

Viscous force, $F = 6 \pi \eta \text{r} \nu$
$\therefore \eta=\frac{F }{6 \pi \text{r} \nu}$ $\left[\right. \eta \left]\right. = \frac{\left[\right. F \left]\right.}{\left[\right. \text{r} \left]\right. \left[\right. \nu \left]\right.}$
or $[\eta\left]\right.=\frac{\left[\right. MLT^{- 2} \left]\right.}{\left[\right. L \left]\right. \left[\right. LT^{- 1} \left]\right.}$