Mechanical properties of fluids practice · Mixed difficulty

Assertion: When the stopcock over the $U$-tube having a large bubble at its one end and a small bubble at the other end is opened, air flows from the large bubble to the small bubble.
Reason: The pressure inside the large bubble is greater than that inside small bubble.

What is the pressure head in Bernoulli's theorem? ( $p=$ pressure, $\rho=$ density, $g=$ acceleration due to gravity)

The viscous force on a lead shot travelling down with velocity V in a liquid column is F. If the same lead shot travelling down with velocity 3V in an other vertical liquid column is opposed by viscous force 2F, the ratio of the coefficients of viscosities of the liquids is

A large open tank has two holes in the wall. One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth of 9y from the top. When the tank is completely filled with water quantities of water flowing out per second from both the holes is the same . Then R is equal to

Surface tension vanishes at

The surface tension of a soap solution is $2 \times 10^{-2} \mathrm{Nm}^{-1}$. To blow a bubble of radius $1 \mathrm{~cm}$, the work done is

A: If barometer is accelerated upwards, the level of mercury in the tube of barometer will decrease.
R: The effective value of '${g}$' increases while the barometer is accelarated up.

A boat having length 2 m and width 1 m is floating in a lake. When a man stands on the boat, it is depressed by 3 cm. The mass of the man is

The pressure on a swimmer 20 m below the surface of water at sea level is

Blood pressure rises in old age due to arteries becoming narrow. This phenomenon could be explained on the basis of

Two stretched membranes of area$2\mathrm{c}{\mathrm{m}^2}$ and$3\mathrm{c}{\mathrm{m}^2}$ are placed in a liquid at the same depth. The ratio of pressure on them is

The rate of flow of liquid in a tube of radius $r$, length $l$, whose ends are maintained at a pressure difference $p$ is $V=\frac{\pi N p r^4}{\eta l}$, where $\eta$ is coefficient of the viscosity and $N$ is

Increase in pressure at one point of the enclosed liquid in rest is transmitted equally to all other points of liquid". Above statement is in accordance with the

Check the dimensional consistency of the Poiseuille's formula for the laminar flow in a tube: $Q=\frac{\pi R^4\left(p_1-p_2\right)}{8 \eta l}$

Assertion: Paper pins are made to have pointed end.
Reason: Because pointed pins have very small area due to which even for small applied force it exert large pressure on the surface.

The total weight of a piece of wood is 6 kg. In the floating state in water its $\frac{1}{3}$ part remains inside the water. On this floating solid, what maximum weight is to be put such that the whole of the piece of wood is to be drowned in the water?>

A: An ice block with lead short is floating in water. When ice melt completely water level slightly drops.
R: When ice block with less shot is placed in water, volume of displaced water is more then that of the ice block

The rate of flow of liquid through a capillary tube of radius$r$ is$V$ when the pressure difference across the two ends of the capillary is $p$. If pressure is increased by 3 $p$ and radius is reduced to $r/2$, then the rate of flow becomes

Given below are two statements: one is labelled as
Assertion A and the other is labelled as Reason R

Assertion A : A spherical body of radius $\left( {5 \pm 0.1} \right)\,\,{\text{mm}}$ having a particular density is falling through a
liquid of constant density. The percentage error in
the calculation of its terminal velocity is 4%.

Reason R : The terminal velocity of the spherical
body falling through the liquid is inversely
proportional to its radius.

In the light of the above statements, choose the
correct answer from the options given below

Assertion: Water drops take spherical shape when falling freely.
Reason: Water has minimum surface tension among all liquids.

Surface tension depends on

Statement A: Pascal law is working principle of a hydraulic lift.
Statement B: Pressure is equal to thrust per unit area.

An ice block contains a glass ball when the ice melts within the water containing vessel. the level of water

Aerofils are so designed that the speed of air

${X}$ and ${Y}$ are two capillary tubes with lengths ${l}_{{X}}$ and $l_Y$ and with radii $r_X$ and $r_Y$ respectively. When a pressure difference $P$ is maintained between the ends of $X$, the rate of flow of water through $X$ is $10\, \mathrm{cc} / \mathrm{sec}$. ${X}$ and ${Y}$ are now connected in series and the same pressure difference $P$ is maintained across the combination. If $l_{\mathrm{X}}=2 l_{\mathrm{Y}}$ and ${r}_{{X}}={r}_{{Y}}$, rate of flow of water through the combination will be:

Assertion: A rain drop after falling through some height attains a constant velocity.
Reason: At constant velocity, the viscous drag is just equal to its weight.

Water flows through a tunnel in a reservoir of dam towards the turbine installed in the power plant. This is situated ${h} \mathrm{~m}$ below the reservoir. If the ratio of cross-sectional areas of the tunnel at the reservoir and power station is $\eta$, find the speed of the water entering into the turbine.

Shear modulus is zero for

Beyond the critical speed, the flow of fluids becomes

The excess pressure in a soap bubble is thrice that in other one. Then the ratio of their volume is