MCQ
An ideal fluid of density $800 \; kgm ^{-3}$, flows smoothly through a bent pipe (as shown in figure) that tapers in cross-sectional area from $a$ to $\frac{ a }{2}$. The pressure difference between the wide and narrow sections of pipe is $4100 \; Pa$. At wider section, the velocity of fluid is $\frac{\sqrt{x}}{6} \; ms ^{-1}$ for $x = \dots$ $\left(\right.$ Given $g =10 \; m ^{-2}$ )
  • $363$
  • B
    $373$
  • C
    $383$
  • D
    $393$

Answer

Correct option: A.
$363$
a
From continuity equation

$a v _{1}=\frac{ a }{2} v _{2}$

$v _{2}=2 v _{1}$

From Bernoulli's theorem,

$P _{1}+\rho g h_{1}+\frac{1}{2} \rho v _{1}^{2}= P _{2}+\rho g h_{2}+\frac{1}{2} \rho v _{2}^{2}$

$P _{1}- P _{2}=\rho\left[\left(\frac{ v _{2}^{2}- v _{1}^{2}}{2}\right)+ g \left( h _{2}- h _{1}\right)\right]$

$4100=800\left[\left(\frac{4 v _{1}^{2}- v _{1}^{2}}{2}\right)+10 \times(0-1)\right]$

$\frac{41}{8}+10=\frac{3 v _{1}^{2}}{2}$

$\frac{121}{8} \times \frac{2}{3}= v _{1}^{2}$

$v _{1}=\sqrt{\frac{ I 21}{4 \times 3} \times \frac{3}{3}}$

$v _{1}=\frac{\sqrt{363}}{6} \; m / s$

$X =363$

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

Similar questions

If a car at rest accelerates uniformly to a speed of $144\ km/ h$ in $20s$, it covers a distance of:
A boy is standing on top of a tower of height $85 \,m$ and throws a ball in the vertically upward direction with a certain speed. If $5.25$ s later he hears the ball hitting the ground, then the speed with which the boy threw the ball is .......... $m / s$ (take, $g=10 \,m / s ^2$ and speed of sound in air $=340 \,m / s$ )
The figure shows a velocity-time graph of a particle moving along a straight line  The correct displacement-time graph of the particle is shown as
In a diatomic molecule, the rotational energy at a given temperature.
  1. Obeys Maxwell’s distribution.
  2. Have the same value for all molecules.
  3. Equals the translational kinetic energy for each molecule.
  4. Is $(2/3)^{rd}$ the translational kinetic energy for each molecule.
Four cylinders contain equal number of moles of argon, hydrogen, nitrogen and carbon dioxide at the same temperature. The energy is minimum in:
If $L , C$ and $R$ denote the inductance, capacitance and resistance respectively, the dimensional formula for $C ^{2} LR$ is
A spring is stretched by $0.20\, m$, when a mass of $0.50\, kg$ is suspended. When a mass of $0.25\, kg$ is suspended, then its period of oscillation will be .... $\sec$   $(g = 10\,m/{s^2})$
Asseretion $A:$ If in five complete rotations of the circular scale, the distance travelled on main scale of the screw gauge is $5\, {mm}$ and there are $50$ total divisions on circular scale, then least count is $0.001\, {cm}$.

Reason $R:$ Least Count $=\frac{\text { Pitch }}{\text { Total divisions on circular scale }}$

In the light of the above statements, choose the most appropriate answer from the options given below:

For matter to exist simultaneously in gas and liquid phases
The energy directly related to the speed of a moving body and its mass is: