Question

The S.I unit of viscosity is _________.

Answer 1

Viscosity

The resistance of a fluid to a change in shape or movement of adjacent sections relative to one another is called viscosity.

Calculating SI unit:

Unit viscosity can be defined as the force of friction required to maintain velocity difference of $1\frac{m}{s}$between two parallel layers of liquid 1m apart and each having an area of $1m^2$

It is expressed as,

$\mu =\frac{F}{A}\frac{u}{y}$

Where $\mu$= viscosity of the fluid

$F$ = Force

$A$ = Area of each plate

$\frac{u}{y}$ = rate of shear deformation.

Now, the SI unit of $F$ is Newton $\left(N\right)$, $A$ is meter square $\left(m^2\right)$, and $\frac{u}{y}$ is seconds $\left(s\right)$

$\mu =\frac{N}{m^2}s$

$\mu =N{m}^{-2}s$

Hence, the SI unit of Viscosity is $N{m}^{-2}s$.