Q: The SI unit of coefficient of viscosity ($\neta$) is:

The SI unit of coefficient of viscosity is Pascal-second ($\ntext{Pa}\cdot\text{s}$) or $\text{N}\cdot\text{s/m}^2$. Poise is the CGS unit ($1 \text{ Pa}\cdot\text{s} = 10 \text{ poise}$).

Question 1

The SI unit of coefficient of viscosity ($
eta$) is:

Accepted Answer

The SI unit of coefficient of viscosity is Pascal-second ($
text{Pa}\cdot	ext{s}$) or $	ext{N}\cdot	ext{s/m}^2$. Poise is the CGS unit ($1 	ext{ Pa}\cdot	ext{s} = 10 	ext{ poise}$).

Question 2

How does the terminal velocity ($vt$) of a small spherical body falling through a viscous fluid depend on its radius ($r$)?

Accepted Answer

According to Stokes' Law, terminal velocity is given by $vt = \frac{2}{9}\frac{r^2(ho - \sigma)g}{
eta}$. Therefore, $vt \propto r^2$.

Question 3

Bernoulli's theorem is based on the law of conservation of:

Accepted Answer

Bernoulli's theorem states that for an incompressible, non-viscous fluid in streamlined flow, the total energy (pressure energy + kinetic energy + potential energy) per unit mass remains constant. Thus, it expresses conservation of energy.

Question 4

A Venturimeter is a device used to measure:

Accepted Answer

A Venturimeter is based on Bernoulli's principle and is used to measure the rate of flow (volume flow rate) of a liquid through a pipe.

Question 5

According to Stokes' Law, the viscous force ($F$) acting on a sphere of radius $r$ moving with velocity $v$ in a fluid of viscosity $
eta$ is given by:

Accepted Answer

Stokes' Law states that viscous drag force acting on a small sphere moving in a viscous fluid is $F = 6\pi\eta rv$.

Mechanical Properties of Fluids