Download App

STD 11 - 9.1. fluid mechanics — NEET STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceNEETSTD 11 - 9.1. fluid mechanics4 Marks
MCQ
A space $2.5\ cm$ wide between two large plane surfaces is filled with oil. Force required to drag very thin plate of area $0.5\ m^2$ just midway the surfaces at a speed of $0.5\ m/sec$ is $1\ N$ The coefficient of viscosity in $kg-s/m^2$ is :
  • A
    $5\,\, \times \,{10^{ - 2}}$
  • ✓
    $2.5\,\, \times \,\,{10^{ - 2}}$
  • C
    $1\,\, \times \,{10^{ - 2}}$
  • D
    $7.5\,\, \times \,\,{10^{ - 2}}$
✓

Answer

Correct option: B.
$2.5\,\, \times \,\,{10^{ - 2}}$
b
Velocity gradient $=\frac{0.5}{\frac{2.5}{2} \times 10^{-2}}$

as force on the plate due to viscosity is from upper as well as lower portion of the oil, equal from each part,

Then, $\mathrm{F}=2 \eta \mathrm{A} \frac{\mathrm{dv}}{\mathrm{dz}}=2 \times \eta \times(0.5) \frac{0.5}{1.25 \times 10^{-2}}$

$\Rightarrow \eta=2.5 \times 10^{-2} \mathrm{kg}-\mathrm{sec} / \mathrm{m}^{2}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

NEET STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

If an $AC$ main supply is given to be $220\,V$. The average $emf$ during a positive half cycle will be.....$V$
→
$Assertion$ : If no external force acts on a system of particles, then the centre of mass will not move in any direction

$Reason$ : If net external force is zero, then the linear momentum of the system changes

→
The charges on two sphere are $+7\,\mu C$ and $-5\,\mu C$ respectively. They experience a force $F$. If each of them is given and additional charge of $-2\,\mu C$, the new force of attraction will be
→
Three identical bulbs are connected as shown in figure. When switch $S$ is closed, the power consumed in bulb $B$ is $P$. What will be the power consumed by the same bulb when switch $S$ is opened?
→
If $3$ charges are placed at the vertices of equilateral triangle of charge ‘$q$’ each. What is the net potential energy, if the side of equilateral triangle is $l\, cm$
→
Light wave traveling in air along $x$-direction is given by $E _{ y }=540 \sin \pi \times 10^{4}( x - ct ) Vm ^{-1}$. Then, the peak value of magnetic field of wave will be $\dots \times 10^{-7}\,T$ (Given $c =3 \times 10^{8}\,ms ^{-1}$ )
→
A body starts from the origin and moves along the $X-$axis such that the velocity at any instant is given by $(4{t^3} - 2t)$, where $t$ is in sec and velocity in$m/s$. What is the acceleration of the particle, when it is $2\, m$ from the origin..........$m/{s^2}$
→
A thin wire of length $l$ and mass $M$ is bent in the form of a semi-circle. What is its moment of inertia about an axis passing through the ends of the wire
→
In a thermodynamics process, pressure of a fixed mass of a gas is changed in such a manner that the gas releases $20\,J$ of heat and $8\,J$ of work is done on the gas. If the initial internal energy of the gas was $30\,J$. The final internal energy will be...... $J$
→
$Assertion :$ Hollow shaft is found to be stronger than a solid shaft made of same equal material.
$Reason :$ Torque required to produce a given twist in hollow cylinder is greater than that required to twist a solid cylinder of same length and material.
→