Question

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

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

Answer 1

Answer: (C)

Viscous force, $F=6\pi \eta \text{r}\nu$
$\therefore \eta =\frac{F}{6\pi \text{r}\nu }$ $[\eta ]=\frac{[F]}{[\text{r}][\nu ]}$
or $[\eta ]=\frac{[ML{T}^{-2}]}{[L][L{T}^{-1}]}$