Question

Define Viscosity. What are itsunits and

dimensions?6.Why are drops and

bubbles Spherical?​

Answer 1

Answer:

Viscosity is the property of a fluid to resist it's flow.

It's relation is expressed with the following expression:

$\\\tt F = \dfrac{A \eta \ dv} {dx}$

Where A =  area in contact

F = force required

v = velocity

x= distance between the plates

and $\\\tt \eta$ = coefficient of viscosity

Therefore,

$\\\tt \eta = \dfrac{F.dx }{A dv}$

Using dimensional analysis, we have the dimensions as

$\\\tt MLT^{-2} . L . (L^{-2}) . (L^{-1}T)\\\\\tt = M L^{-1}T^{-1}$

Bubble drops are spherical because the individual particles apply force on each other so that  the surface trends to gain a minimum area surface which is possible only in the form of a sphere.

Answer 2

Required Answer :-

1]Viscosity is defined as the amount of fluid that are required to flow in a resistor.

It's units are :-

n/s²

Where n = newton

s = second

But SI unit of Viscosity is different which is

pa/s

Where

pa = pascal

s = second

The dimension is

$\sf ML^{-1}T^{-1}$

2]

The drops and bubbles are due to the attractive force of the surface.