Question

Which one of the following represents the correct dimensions of the coefficient of viscosity?

1. ML^-1T^-1
2. MLT^-1
3. ML^-1T^-2
4. ML^-2T^-2

Answer 1

option 1 is correct 

From stokes law, Viscous force F = $6\pi \eta rv$

$\Rightarrow \eta =\frac{F}{6\pi rv}$

$\therefore [\eta ]=\frac{[ML{T}^{-2}]}{[L][L{T}^{-1}]}$

$\Rightarrow [\eta ]=[M{L}^{-1}{T}^{-1}]$