A spherical body of mass $m$ and radius $r$ is allowed to fall in a medium of viscosity $\eta $. The time in which the velocity of the body increases from zero to $0.63$ times the terminal velocity $(v)$ is called time constant $(\tau )$. Dimensionally $\tau $ can be represented by
A spherical body of mass $m$ and radius $r$ is allowed to fall in a medium of viscosity $\eta $. The time in which the velocity of the body increases from zero to $0.63$ times the terminal velocity $(v)$ is called time constant $(\tau )$. Dimensionally $\tau $ can be represented by
$\frac{{m{r^2}}}{{6\pi \eta }}$
$\sqrt {\left( {\frac{{6\pi mr\eta }}{{{g^2}}}} \right)} $
$\frac{m}{{6\pi \eta rv}}$
None of the above
A spherical body of mass $m$ and radius $r$ is allowed to fall in a medium of viscosity $\eta $. The time in which the velocity of the body increases from zero to $0.63$ times the terminal velocity $(v)$ is called time constant $(\tau )$. Dimensionally $\tau $ can be represented by
Time constant $\tau = [T]$ and Viscosity $\eta = [M{L^{ - 1}}{T^{ - 1}}]$
For options $(a)$, $(b)$ and $(c)$ dimensions are not matching with time constant.
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