JEE MAIN - Physics (2004 - No. 67)
Which one of the following represents the correct dimensions of the coefficient of viscosity?
ML-1T-1
MLT-1
ML-1T-2
ML-2T-2
Explication
From stokes law, Viscous force F = $$6\pi \eta rv$$
$$ \Rightarrow \eta = {F \over {6\pi rv}}$$
$$\therefore$$ $$[\eta] = {[{ML{T^{ - 2}}]} \over {[L][L{T^{ - 1}}]}}$$
$$ \Rightarrow [\eta] = [M{L^{ - 1}}{T^{ - 1}}]$$
$$ \Rightarrow \eta = {F \over {6\pi rv}}$$
$$\therefore$$ $$[\eta] = {[{ML{T^{ - 2}}]} \over {[L][L{T^{ - 1}}]}}$$
$$ \Rightarrow [\eta] = [M{L^{ - 1}}{T^{ - 1}}]$$