Question 2 :
If the meniscus of a liquid is concave in shape, then
Question 3 :
What is ratio of surface energy of $1$ small drop and $1$ large drop, if $1000$ small drops combined to form $1$ large drop<br>
Question 4 :
Assertion: The upper surface of the wings of an aeroplane is made convex<br/>Reason: The air current at the top will have greater velocity and thus pressure at the bottom will be greater than at the top
Question 5 :
In a laminar flow the velocity of the liquid in contact with the walls of the tube is
Question 7 :
The end of a glass tube becomes round on heating due to:
Question 9 :
Eight drops of equal size are falling through air with steady velocity of 10 cm/sec. If the drops coalesce, what could be its terminal velocity?
Question 10 :
The wettability of a surface by a liquid depends primarily on:<br/>
Question 11 :
A small metal sphere of radius $a$ is falling with a velocity $v$ through a vertical column of a viscous liquid. If the coefficient of viscosity of the liquid is $\eta $, then the sphere encounters an opposing force of:
Question 13 :
The excess pressure inside a spherical soap bubble of radius $1\ cm$ is balanced by a column of oil (specific gravity $= 0.8), 2\ mm$ high, the surface tension of the bubble is :
Question 14 :
If the surface tension of water is $0.06N/m$, then the capillary rise in a tube of a diameter $1mm$ is :($\theta={0}^{o}$)
Question 15 :
The tangential forces per unit area of the liquid layer required to maintain unit velocity gradient is known as:
Question 17 :
<br>In the hydraulic braking system , the piston in the master cylinder is connected by mechanical linkage to the
Question 19 :
Bernoulli's principle is based on the law of conservation of :
Question 20 :
The velocity of the wind over the surface of the wing of an aeroplane is 80 ms$^{-1}$ and under the wing 60 ms$^{-1}$. If the area of the wing is 4m$^{2}$, the dynamic lift experienced by the wing is [ density of air $=$ 1.3 kg. m$^{-3}$]:
Question 22 :
A drop of mercury of radius $2 mm$ is split into 8 identical droplets. Find the increase in surface energy. (Surface tension of mercury is $0.465{ J/m }^{ 2 }$)
Question 23 :
If air is blown through the space between a calendar suspended from a nail on wall and the wall, then:
Question 25 :
Two spheres of the same material, but of radii R and 3R are allowed to fall vertically downwards through a liquid of density $\sigma$. The ratio of their terminal velocities is
Question 26 :
The flow of liquid is laminar or steamline is determined by
Question 27 :
A small steel ball falls through a syrup at a constant speed of $10 cm/sec.$ If the steel ball is pulled upwards with a force equal to twice its effective weight; how fast will it move upwards?
Question 28 :
Bernoulli's theorem is a consequence of the law of conservation of :
Question 29 :
Two separate air bubble (radii 0.002 m and 0.004 m) formed of the same liquid (surface tension 0.07 $Nm^{-1}$)come together to form a double bubble. The radius and the sense of curvature of internal film surface, common to both the bubbles is:
Question 30 :
No capillarity will take place if:-<br>(i) The liquid is at its boiling point<br>(ii) The liquid is at its freezing point<br>(iii) The angle of contact is $0^{\circ}$<br>(iv) The angle of contact is $90^{\circ}$<br>
Question 32 :
Curve in the upper surface of a liquid to the surface of the container is known as
Question 33 :
Assertion: The shape of a liquid drop is spherical.
Reason: The pressure inside the drop is greater than that of outside.
Question 34 :
The unit of the coefficient of viscosity in S.I. system is:<br/>
Question 35 :
The surface tension of a liquid is $5 N/m$. If a thin film of the area $0.02 m^{2}$ is formed on a loop, then its surface energy will be<br>
Question 37 :
When a sphere falling in a viscous fluid attains a terminal velocity, then:
Question 39 :
The rate of flow of liquid through a capillary tube, in an experiment to determine the viscosity of the liquid, increases :
Question 40 :
A jet of water with area of cross-section 3cm$^2$ strikes a wall at an angle $\theta = 60^o$ to the normal and be rebounds elastically from the wall with the same speed. If the speed of water in the jet is 12 m/s, then the force acting on the wall is
Question 41 :
A raindrop falls near the surface of the earth with almost uniform velocity because:<br/>
Question 42 :
A copper ball of radius $r$ is moving with a uniform velocity $v$ in the mustard oil and the dragging force acting on the ball is $F$. The dragging force on the copper ball of radius $2r$ with uniform velocity $2v$ in the mustard oil is
Question 43 :
If the diameter of a soap bubble is 20 mm and if the surface tension of soap water is 0.04N.m$^{-1}$, the excess pressure inside the bubble is in Nm$^{-2}$ is :<br/>
Question 44 :
The surface tension of soap solution is $0.03 {N}/{m}$. The work done in blowing to from a soap bubble of surface area $40{ cm }^{ 2 }$, (in $J$), is
Question 45 :
The gale blows over a house. The force due to gale on the roof is:-
Question 46 :
In old age arteries carrying blood in the human body become narrow resulting in an increase in the blood pressure. This follows from:
Question 48 :
Two soap bubbles each of radius r are touching each other. The radius of curvature of the common surface will be :-
Question 50 :
A car moving on a road when overtaken by a bus:
Question 51 :
Assertion: A liquid will flow faster and more smoothly from a sealed can when two holes are punched in the can than when one hole is punched.
Reason: The flow becomes streamlined with two holes rather than with one hole.
Question 52 :
If the difference between pressure inside and outside of a soap bubble is 6 mm of water above atmospheric pressure and its radius is 8 mm. What is the surface tension in dynes per cm :<br/>
Question 53 :
Assertion: When fluids flow, there is some loss of energy due to friction.
Reason: Different layers of the fluid exert forces on each other.
Question 54 :
Spherical balls of radius R are falling in a viscous fluid of velocity v. The retarding viscous force acting on the spherical ball is
Question 55 :
A large tank is filled with water to a height H. A small hole is made at the base of the tank. It takes 71 time to decrease the height of water to $\frac {H}{\eta }(\eta > 1)$ and $T_2$ time to take out the rest of 11 water. If $T_1 = T_2$ then the value of $\eta$ is
Question 56 :
The amount of energy dissipated when $8$ water drops of  $0.6\ mm$ radius coalesce to form one big drop is _________ $J$ $($given surface tension of water is  $0.072 Nm^{-1})$
Question 57 :
Water is floating smoothly through a closed-pipe system. At one point A, the speed of the water is 3.0 m/s while at another point B, 1.0 m higher, the speed is 4.0 m/s. The pressure at A is 20 kPa when the water is flowing and 18 kPa when the water flow stops. Then<br>
Question 58 :
Assertion: Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift.
Reason: According to Bernoulli's theorem, as velocity increases pressure decreases and viceversa.
Question 59 :
Assertion : Falling raindrops acquire a terminal velocity.<br>Reason : A constant force in the direction of motion and a velocity dependent force opposite to the direction of motion, always result in the acquisition of terminal velocity.
Question 60 :
The excess pressure inside a small air bubble of radius $0.05 mm$ in water of surface tension $70\ dyne- cm^{-1}$ is $Pa$:
Question 61 :
A big drop of radius $R$ is formed by $729$ small drops of water of radius $r$, then the radius of each small drop will be
Question 62 :
A gale is on a house. The force on the roof due to the gale is:
Question 63 :
Assertion: The velocity of horizontal flow of a ideal liquid is smaller where pressure is large and vice versa.
Reason: According to Bernoulli's theorem for the stream line flow of an ideal liquid, the total energy per unit mass remains constant.
Question 64 :
Two drops of same radius are falling through air with steady velocity of $v cm/s$. If the two drops coalesce, what would be the terminal velocity?<br>
Question 65 :
Assertion: Small liquid drops assume spherical shape.
Reason: Due to surface tension liquid drops tend to have minimum surface area.
Question 66 :
The flow of blood in a large artery of an anesthetised dog is diverted through a venturi meter. The wider part of the meter has a cross-sectional area equal to that of the artery $A=8 \ mm^2$ .The narrower part has an area $a=4 \ mm^2$.The pressure drop in the artery is 24 Pa. What is the speed of blood in the artery?Density of blood is $ 1.06\times 10^3 kg/m^3$.<br>
Question 67 :
The pressure of water in a water pipe when tap is opened and closed in respectively $3\times 10^{5}N/m^{2}$ and $3.5\times 10^{5} N/m^{2}$. Determine the velocity of flow when tap is open?
Question 68 :
The pressure of air inside a soap bubble of diameter $0.7 \ cm$ is $8\ mm$ of water above atmospheric pressure. The surface tension of soap solution is :<br/>
Question 69 :
A solid sphere falls with a terminal velocity of $20m/s^{-1}$ in air. If it is allowed to fall in vacuum
Question 70 :
To measure the radius of the drop Millikan used _____ law of freely falling drops.
Question 71 :
Two drops of small radius are falling in air with constant velocity $5 cms^{-1}$. If they coalesce, then the terminal velocity will be
Question 72 :
A water tank of height $10m$, completely filled with water is placed on a level ground. It has two holes one at $3 m$ and the other at $7 m$ from its base. The water ejecting from:
Question 73 :
Assertion: An object falling from a great height may reach a steady terminal velocity.
Reason: The viscous force on the body is responsible for this steady terminal velocity.
Question 74 :
The motion of a body is given by the equation $\dfrac{dv}{dt} = 6-3v:$where $v$ is in $m/s$. If the body was at rest at $t=0$ <br/>(i) the terminal speed is $2\ m/s$<br/>(ii) the magnitude of the initial acceleration is $6\ m/s$<br/>(iii) the speed varies with time as $v=2(1-e^{-3t})m/s$<br/>(iv) The speed is $1\ m/s$, when the acceleration is half the initial <br/>
Question 75 :
In the streamlined flow of a liquid, the power due to pressure difference between the ends of the tube is<br>
Question 76 :
If the terminal speed of a sphere of gold (density =$\displaystyle 19.5{ kg }/{ { m }^{ 3 } }$) is $0.2 m/s$ in a viscous liquid(density = $\displaystyle 1.5{ kg }/{ { m }^{ 3 } }$), find the terminal speed of a sphere of silver (density = $\displaystyle 10.5{ kg }/{ { m }^{ 3 } }$) of the same size in the same liquid
Question 77 :
Assertion: An object from a greater height reaches a steady terminal velocity.
Reason: The viscous forces on a body depends upon its velocity. The greater the velocity the greater is the viscous force.
Question 78 :
A tank with vertical walls is mounted so that its base is at a height $H$ above the horizontal ground. The tank is filled with water to a depth '$h$' . A hole is punched in the side wall of the tank at a depth ' $x$ ' below the water surface. To have maximum range of the emerging stream,the value of $x$ is
Question 79 :
The velocity of a ball of mass m density d1d1 becomes constant after some time.The viscous force acting on the ball will be:
Question 80 :
A ball of mass $m$ and radius $r$ is released in a viscous liquid. The density of the liquid is negligible compared to that of the ball.The value of its terminal velocity is proportional to:<br>
Question 81 :
A hole is made at the bottom of a tank filled with water $\left(density={10}^{3}kg/m^{3}\right)$. If the total pressure at the bottom of the the tank is $3atm\left(1atm=10^{5}{N/m}^{2}\right)$, then the velocity of efflux is
Question 82 :
A liquid is filled upto a height of $20\ m$ in a cylindrical vessel. The speed of liquid coming out of a small hole at the bottom of the vessel is (take, $g = 10\ ms^{-2}$).
Question 83 :
A horizontal pipe of non-uniform cross-section allows water to flow through it with a velocity 1ms$^{-1}$ when pressure is 50kPa at a point. If the velocity of flow has to be 2 ms$^{-1}$ at some other piont,the pressure at that point should be:
Question 85 :
The rain drops falling from the sky neither injure us nor make holes on the ground because they move with:
Question 86 :
Water is flowing in streamline motion through a horizontal tube. The pressure at a point in the tube is $p$ where the velocity of flow is $v$. At another point, where the pressure is $p/2$, the velocity of flow is [density of water = $\rho$]
Question 87 :
An air bubble of radius $1.0 \ cm$ rises with a constant speed of $3.5 \ mm/s$ through a liquid of density $1.75 \times 10^{3} kg/m^{3}$. The coefficient of viscosity of the liquid is: (Neglect the density of air)
Question 89 :
A large number of droplets, each of radius $a$, coalesce to form a bigger drop of radius $b$. Assume that the energy released in the process is converted into the kinetic energy of the drop. The velocity of the drop is ($\sigma=$surface tension, $\rho=$density)<br>
Question 90 :
The radius of a soap bubble is $4 cm.$ The radius of the drop formed by soap solution is $2cm.$ The ratio of excess pressures in the two is:
Question 91 :
A drop of water of radius 0.0015 mm is falling in air. If the coefficient of viscosity of air is $2.0 \times 10^{-5} kg m^{-1} s^{-1}$, the terminal velocity of the drop will be:<br/>(The density of water = $10^3 kg m^{-3}$ and $g = 10 m s^{-2}$)
Question 92 :
A wind - powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed $V$, the electrical power output will be proportional to
Question 93 :
Water from a tap emerges vertically down with an initial speed of $1.0\ ms^{-1}$. The cross sectional area of tap is $10\ cm^{2}$. Assume that the pressure is constant through out the stream of water,and that the flow is steady, the cross sectional area of the steam $0.15\ m$ below the tap is
Question 94 :
Which one of the following represents the correct dimensions of the quantity $x=\dfrac{\eta }{\rho }$,where $\eta=$ coefficient of viscosity and $\rho=$ the density of a liquid?
Question 95 :
The terminal velocity $\left (V_c \right) $ of a small sphere falling under gravity in a viscous liquid is related to its radius as<br>
Question 96 :
A small metal ball of diameter $4\ mm$ and density $10.5\ g/cm^{3}$ in dropped in glycerine of density $1.5\ g/cm^{3}$. The ball attains a terminal velocity of $8\ cm/\sec$. The coefficient of viscosity of glycerine is
Question 97 :
Eight drops of water, each of radius 2 mm are falling through air at a terminal velocity of $8 cm s^{-1}$. If they coalesce to form a single drop, then the terminal velocity of combined drop will be:
Question 98 :
Three points $A, B$ and $C$ on a steady flow of a non viscous and incompressible fluid are observed. The pressure, velocity and height of the points $A, B $ and $C$ are $(2,3, 1). (1, 2, 2)$and $(4, 1, 2)$ respectively. Density of the fluid is $1 kgm^{-3}$ and all otner parameters are given in SI units. Then which of the following is correct? $(g = 10 ms ^{-2})$<br/>
Question 99 :
If $ \eta $ represents the coefficient of viscosity and $T$ the surface tension, then the dimension of $ \dfrac{T}{\eta} $ is same as that of :
Question 100 :
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= \dfrac { \pi Qp{ r }^{ 4 } }{ \eta l } $, where $\eta$ is coefficient of the viscosity and $Q$.<br/>
Question 101 :
A sphere of mass m and radius $r$ is projected in a gravity free space with speed $v$. If coefficient of viscosity of the medium in which, it moves is $\dfrac{1}{6\pi}$, then the distance travelled by the body before it stops, is:
Question 102 :
A thin square plate of side $5\ cm$ is suspended vertically from a balance so that lower side just dips into water with side to surface. When the plate is clean $(\theta = 0^{\circ})$, it appears to weigh $0.044\ N$. But when the plate is greasy $(\theta = 180^{\circ})$, it appears to weigh $0.03\ N$. The surface tension of water 
Question 103 :
The atmospheric pressure and height of barometer column is $10^5 P_a$ and 760mm respectively on the earth surface. If the barometer is taken to moon then column height will be
Question 104 :
Given three statements:<br>(i) Speed of liquid increases at a constriction.<br>(ii) If speed increases, pressure in a fluid also increases.<br>(ill) lf distance between streamlines decreases, the velocity increases. Then,<br>
Question 105 :
The angle of contact at the interface of water glass is ${0^ \circ }$, Ethyl-alcohol glass is ${0^ \circ }$ Mercury glass is ${140^ \circ }$ and Methyl iodide is ${30^ \circ }$. A glass capillary is put in a trough containing one of these for liquids it is observed that the meniscus is convex. the liquid in the trough is :      
Question 106 : Match column I with column II :<br><table class="wysiwyg-table"><tbody><tr><td>List I</td><td>List II</td></tr><tr><td>Magnus energy</td><td>Pascal's Law</td></tr><tr><td>Loss of Energy</td><td>Archimedes' principle</td></tr><tr><td>Pressure is same at same level in a liquid</td><td>Viscous force </td></tr><tr><td>Hydraulic Machines</td><td>Lifting of asbestos roofs</td></tr></tbody></table>
Question 108 :
In a meniscus of radius $r$, with excess pressure $p$ in atmospheric pressure $p_{0}$, the force experienced
Question 109 :
A liquid is flowing in a horizontal uniform capillary tube under a constant pressure difference p. The value of pressure for which the rate of flow of the liquid is doubled when the radius and length both are doubled, is
Question 110 :
If 'n' identical water drops assumed spherical each charged to a potential energy U coalesce to a single drop, the potential energy of the single drop is: (Assume that drops are uniformly charged).
Question 111 :
A capillary tube with inner cross-section in the form of a square of side a is dipped vertically in a liquid of density $ \rho $ and surface tension $ \sigma $ which wet the surface of capillary tube with angle of contact $ \theta $. The approximate height to which liquid will be raised in the tube is : (Neglect the effect of surface tension at the corners of capillary tube)
Question 112 :
If the radius of a soap bubble is four times that of another, then the ratio of their pressure will be.
Question 113 :
Air is streaming past a horizontal airplane wing such that its speed is $90 ms^{-1}$ at the lower surface and $120 ms^{-1}$ over the upper surface. If the wing is 10 m long and has an average width of 2m, the difference of pressure on the two sides and the gross lift on the wing respectively, are (density of air $=1.3 kg m^{-3})$<br>
Question 114 :
A Cylindrical vessel filled with water upto height of h stands on a horizontal plane. The side  wall of the vessel has a plugged circular hole touching the bottom. The coefficient of friction between the bottom of vessel and plane is $\mu$ and total mass of water plus vessel is m. What should be minimum diameter of hole so that the vessel begins to move on the floor if plug is removed (here density of water is $\rho$):
Question 115 :
On charging a soap bubble, its radius increases. This is because <br/>
Question 116 :
A metallic shpere of radius $\displaystyle 1.0\times 10^{-3}m$ and density $\displaystyle 1.0\times 10^{4}kg/m^{3}$ enters a tank of water after a free fall, falling through a distance of h in the earth's gravitational field. If its velocity remains unchanged after entering water, determine the value of h. <br/>[Given : coefficient of viscosity of water = $\displaystyle 1.0\times 10^{-3}N-s/m^{2},g=10m/s^{2}$ and density of water = $\displaystyle 1.0\times 10^{3}kg/m^{3}$]
Question 117 :
If soap bubbles of different radii are in communication with each other
Question 118 :
A soap bubble of radius $r$ is blown up to form a bubble of radius $2 r$ under isothermal conditions. If $T$ is the surface tension of soap solution, the energy spent in the blowing(in J) is:<br/>
Question 119 :
A capillary tube is attached horizontally to a constant pressure head arrangement. If the radius of the capillary tube is increased by $10$%, then the rate of flow of the liquid shall change nearly by<br/>
Question 120 :
A cylindrical vessel of cross-sectional area $1000 cm^2$, is fitted with a frictionless piston of mass $10 kg$, and filled with water completely. A small hole of cross-sectional area $10 mm^2$ is opened at a point $50 cm$ deep from the lower surface of the piston. The velocity of efflux from the hole will be
Question 121 : <p>STATEMENT-1 : At two different points on the same stream line in streamline flow, velocity of a particle may be different.<br>STATEMENT-2 : Pressure and height may be different at two different points on a streamline.</p>
Question 122 :
Earthly particles in an ore are removed from heavier metal ore using water in:<br/>
Question 123 :
A drop of water of radius 0.0015 mm is falling in air. If the coefficient of viscosity of air is $\displaystyle 1.8\times 10^{-5}kg/m \ s$, what will be the terminal velocity of the drop? (density of water = $\displaystyle 1.0\times 10^{3}kg/m^{2}$ and g = 9.8 N/kg). The density of air can be neglected
Question 124 :
Three immiscible liquid of densities ${ d }_{ 1 }$ > ${ d }_{ 2 }$ > ${ d }_{ 3 }$ and refractive indices $\mu_{ 1 }$ > $\mu_{ 2 }$ > $\mu_{ 3 }$ are put in a beaker. The height of each liquid column is $\dfrac { h }{ 3 }$. A dot is made at the bottom of the beaker. For near normal vision, find the apparent depth of the dot.
Question 125 :
Three containers are used in a chemistry lab. All containers have the same bottom area and the same height. A chemistry student fills each of the containers with the same liquid to the maximum volume. Which of the following is true about the pressure on the bottom in each container?
Question 126 :
A liquid flows through two capillary tubes connected in series. Their lengths are $L$ and $2L$ and radii $r$ and $2r$ respectively. Then the pressure differences across the first and the second tube are in the ratio
Question 127 :
A sphere of mass M and radius R is falling in a viscous fluid. The terminal velocity attained by the falling object will be proportional to :
Question 128 :
A rain drop of radius $1.5$mm, experience a drag force $F=(12\times10^{-5}v)N$, while falling through air from a height $2$km, with a velocity v. The terminal velocity of the rain drop will be nearly $(use {\,}g=10m/s^2)$
Question 129 :
The area of cross section of a large tank is $0.5 m^2$.It has a opening near the bottom having area of cross section $1 cm^2$.A load of 20 kg is applied on the water at the top.Find the velocity of the water coming out of the opening at the time when the height of the water level is50 cm above the bottom.Taking g=$10 m/ s^2$.<br/>
Question 130 :
A sphere of mass $m$ and radius $r$ is projected in a gravity free space with speed $v$. If coefficient of viscosity is $\dfrac{1}{6\pi}$, then the distance travelled by the body before it stops is <br/>
Question 131 :
Two parallel wires each of length $10cm$ are $0.5cm$ apart. A film of water is formed between them. If the surface tension of water is $0.072N/m$, then the work done in on increasing the distance between the wires by $1mm$ is<br>
Question 132 :
In a cylindrical vessel containing liquid of density $\rho$, there are two holes in the side walls at heights of $h_1$ and $h_2$ respectively such that the range of efflux at the bottom of the vessel is same. Find the height of a hole, for which the range of efflux would be maximum.
Question 133 :
A cube of Ice is floating in water. The fraction of its length lie outside the water is (sp. Gravity of Ice $= 0.96$)
Question 134 :
The force acting on a window of area 50 cm x 50 cm of a submarine at a depth of 2000 m in an ocean, the interior of which is maintained at sea level atmospheric pressure is (Density of sea water = 10$^3$ kg m$^{-3}$,g = 10 m s$^{-2}$)
Question 135 :
A cylinder with a movable piston contains air under a pressure $\displaystyle P_{1}$ and a soap bubble of radius 'r'. The pressure $\displaystyle P_{2}$ to which the air should be compressed by slowly pushing the piston into the cylinder for the soap bubble to reduce its size by half will be (The surface tension is $\displaystyle \sigma$ and the temperature T is maintained constant)
Question 136 :
A solid sphere falls with a terminal velocity of 10 m/s in air. If it is allowed to fall in vacuum:<br/>
Question 137 :
If the excess pressure inside a soap bubble of radius ${ r }_{ 1 }$ in air is equal to the excess pressure inside air bubble of radius ${ r }_{ 2 }$ inside the soap solution, then ${ r }_{ 1 }:{ r }_{ 2 }$ is
Question 138 :
The pressure inside the two soap bubbles is $1.01$ and $1.02$ atmosphere. When they are in air , the ratio of their volumes is (both have same surface tension):
Question 139 :
A water drop is divided into $8$ equal droplets. The pressure difference between the inner and outer side of the big drop will be<br/>
Question 140 :
A light aircraft has a wing area of $15 m^{2}$ and flies at $60 m/s$ in level flight. If the air velocity over the upper surface of the wing is $15\%$ greater, then the magnitude of the lift developed (in $N$) is (nearly) (given: density of air is $1.2 kg/m^{3}$)<br/>
Question 141 :
A plane is in level flight at constant speed and each of its two wings has an area of 25 m$^2$. If the speed of the air on the upper and lower surfaces of the wing are 270 km h$^{-1}$ and 234 km h$^{-1}$ respectively, then the mass of the plane is (Take the density of the air = 1 kg m$^{-3}$)
Question 142 :
A hole is made at the bottom of a tank filled with water (density $=10^3 kg/m^3)$. If the total pressure at the bottom of the tank is $3 atm$ ($1 atm=10^5 N/m^2$), then the velocity of efflux is
Question 143 :
A metal washer has a hole of diameter ${d}_{1}$ and an external diameter ${d}_{2}$, where ${d}_{2}=3{d}_{1}$. On heating ,${d}_{2}$ increases by $0.3\%$. Then ${d}_{1}$ will increase or decrease by what percentage
Question 144 :
If the terminal speed of a sphere of gold (density $\displaystyle =19.5\quad { kg }/{ { m }^{ 3 } }$) is $\displaystyle 0.2{ m }/{ s }$ in a viscous liquid (density $\displaystyle =1.5\quad { kg }/{ { m }^{ 3 } }$), find the terminal speed of a sphere of silver (density $\displaystyle =10.5\quad { kg }/{ { m }^{ 3 } }$) of the same size in the same liquid.
Question 145 :
A tank is filled with two immiscible  liquids of densities $2\rho$ and $\rho$ each of height $h$. Two holes are made to the side wall at $\dfrac{h}{2}$ and $\dfrac{3h}{2}$ from upper surface of the liquid, then the ratio of velocity of efflux of the liquids through the holes
Question 147 :
'$n$' droplets of equal size of radius $r$ coalesce to form a bigger drop of radius $R$. The energy liberated is equal to _________.<br>($T=$ Surface tension of water)
Question 148 : <p>Two hail stones iron the form of a sphere with radii in the ratio 1:2, fall from a great height through the atmosphere. What will be the ratio of their momenta when they attain their respective terminal velocities?</p>
Question 149 :
The surface tension of a liquid is $5 N/m$. If a film of this liquid is held on a ring of area $0.02  {m}^{2} $, its surface energy is about :
Question 150 :
There are two round tables in the physics classroom: one with the radius of $50\ cm$, the other with a radius of $150\ cm$. What is the relationship between the two forces applied on the tabletops by the atmospheric pressure? then value of $\dfrac{F_1 }{F_2} $ is:
