JEE Questions for Physics Mechanical Properties Of Fluids Quiz 3

Eight equal drops of water are falling through air with a steady velocity of 10 cms ^-1. If the drops combine to form a single drop big in size, then the terminal velocity of this big drop is

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80 cms-1
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30 cms-1
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10 cms-1
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40 cms-1

The terminal speed of a sphere of gold (density = 19.5 kg m^-3) is 0.2 ms ^-1 in a viscous liquid (density = 1.5 kg m^-3). Then, the terminal speed of a sphere of silver (density =10.5 kg m^-3) of the same size in the same liquid is

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0.1 ms-1
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1.133 ms-1
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0.4 ms-1
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0.2 ms-1
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0.3 ms-1

A large open tank has two holes in its wall. One is a square hole of side a at a depth of x from the top and the other is a circular hole of radius r at a depth 4x from the top. When the tank is completely filled with water, the quantities of water flowing out per second from both holes are the same. Then r is equal to

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2πa
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a
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0%

Assertion (A) Water flows faster than honey.
Reason (R) The coefficient of viscosity of water is less than honey.

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Both A and R are correct and R is the correct explanation of A
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Both A and R are correct but R is not a correct explanation of A
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A is correct but R is incorrect
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A is incorrect but R is correct

A liquid of density 800 kg m^-3 is filled in a tank open at the top. The pressure of the liquid, at the bottom of the tank is 6.4 atm. The velocity of efflux through a hole at the bottom is (1 atm =10⁵ Nm^-2)

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10 ms -1
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20 ms -1
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30 ms -1
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40 ms -1

A horizontal pipe line carries water in streamline flow. At a point where the cross-sectional area is 10 cm² the water velocity is 1 ms ^-1 and pressure is 2000 Pa. The pressure of water at another point where the cross-sectional area is 5 cm², is

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200 Pa
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400 Pa
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500 Pa
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800 Pa

Physics-Mechanical Properties of Fluids-78434.png

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0%
2)
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0%

A hole is made at the bottom of the tank filled with water (density = 1000 kg/m³). If the total pressure at the bottom of the tank is 3 atm (1 atm =10⁵ N/m²), then the velocity of efflux is

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2)
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Assertion (A) All the rain drops hit the surface of the earth with the same constant velocity.
Reason (R) An object falling through a viscous medium eventually attains a terminal velocity.

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Both A and R are correct and R is the correct explanation of A
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Both A and R are correct but R is not a correct explanation of A
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A is correct but R is incorrect
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A is incorrect but A is correct

Horizontal tube of non-uniform cross-section has radii of 0.1 m and 0.05 m respectively at M and N. For a streamline flow of liquid the rate of liquid flow is
Physics-Mechanical Properties of Fluids-78443.png

Physics-Mechanical Properties of Fluids-78443.png

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changing continuously with time
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greater at M than at N
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greater at N than at M
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same at M and N

A small spherical ball falling through a viscous medium of negligible density has terminal velocity v. Another ball of the same mass but of radius twice that of the earlier falling through the same viscous medium will have terminal velocity

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2)
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A manometer connected to a closed tap reads 3.5 × 10⁵ Nm^-2. When the valve is opened, the reading of manometer falls to 3.0 × 10⁵Nm^-2, then velocity of flow of water is

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100 ms -1
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10 ms -1
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1 ms -1
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A liquid is allowed into a tube of truncated cone shape. Identify the correct statement from the following.

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The speed is high at the wider end and low at the narrow end
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The speed is low at the wider end and high at the narrow end
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The speed is same at both ends in a stream line flow
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The liquid flows with uniform velocity in the tube

A sphere of radius R is gently dropped into liquid of viscosity η in a vertical uniform tube. It attains a terminal velocity v. Another sphere of radius 2R when dropped into the same liquid, will attain its terminal velocity

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v
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2v
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4v
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9v

The cylindrical tube of a spray pump has a cross-section of 8 cm², one end of which has 40 fine holes each of area 10^-8 m². If the liquid flows inside the tube with a speed of 0.15 m min^-1, the speed with which the liquid is ejected through the holes is

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50 ms-1
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5 ms-1
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0.05 ms-1
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0.5 ms-1

A tank of height H is fully filled with water. If the water rushing from a hole made in the tank below the free surface, strikes the floor at maximum horizontal distance, then the depth of the hole from the free surface must be

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2)
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0%

Spherical balls of radius R are falling in a viscous fluid of viscosity η with a velocity v. The retarding viscous force acting on the spherical ball is

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directly proportional to R but inversely proportional to v
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directly proportional to both radius R and velocity v
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inversely proportional to both radius R and velocity v
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inversely proportional to R but directly proportional to velocity v

A layer of glycerine of thickness 1 mm is present between a large surface area and a surface area of 0.1 m². With what force the small surface is to be pulled, so that it can move with a velocity of 1 ms^-1? (given that coefficient of viscosity = 0.07 kg m^-1s^-1 )

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70 N
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7 N
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700 N
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0.70 N

Water is flowing through a horizontal pipe of varying cross-section. If the pressure of water equals 2 cm of mercury, where the velocity of the flow is 32 cms^-1, what is the pressure at another point, where the velocity of flow is 65 cms^-1?

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1.02 cm of Hg
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1.88 cm of Hg
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2.42 cm of Hg
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1.45 cm of Hg

A liquid flows through a pipe of non-uniform cross-section. If A₁ and A₂ are the cross-sectional areas of the pipe at two points, the ratio of velocities of the liquid at these points will be

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2)
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0%

A tank is filled with water of density 1 g cm^-3 and oil of density 0.9 g cm^-3 . The height of water layer is 100 cm and of the oil layer is 400 cm. If g = 980 cms^-2, then the velocity of efflux from an opening in the bottom of the tank is

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2)
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0%

When a body falls in air, the resistance of air depends to a great extent on the shape of the body. Three different shapes are given. Identify the combination of air resistances which truly represents the physical situation? (The cross-sectional areas are the same)
Physics-Mechanical Properties of Fluids-78466.png

Physics-Mechanical Properties of Fluids-78466.png

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1 < 2 < 3
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2 < 3 < 1
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3 < 2 < 1
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3 < 1 < 2

Water flows steadily through a horizontal pipe of variable cross-section. If the pressure of water is p at a point where flow speed is v, the pressure at another point where the flow of speed is 2v , is (take, density of water as ρ )

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2)
0%
0%

Water is filled in a cylindrical container to a height of 3 m. The ratio of the cross-sectional area of the orifice and the beaker is 0.1. The square of the speed of the liquid coming out from the orifice is (take, g = 10 ms ^-2 )
Physics-Mechanical Properties of Fluids-78471.png

Physics-Mechanical Properties of Fluids-78471.png

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50 m2s -2
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50.5 m2s -2
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51 m2s -2
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52 m2s -2

What is the velocity v of a metallic ball of radius r falling in a tank of liquid at the instant when its acceleration is one-half that of a freely falling body? (The densities of metal and of liquid are ρ and σ respectively and the viscosity of the liquid is η )

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0%
2)
0%
0%
0%

A container with square base of side a is filled upto a height H with a liquid. A hole is made at a depth h from the free surface of water.
With what acceleration the container must be accelerated, so that the water does not come out?

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2)
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0%

A ball is made of a material of density ρ where ρ_oil <ρ < ρ_water with ρ_oil and ρ_water representing the densities of oil and water respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position?

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2)
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0%

A wooden block, with a coin placed on its top, floats in water as shown in the figure. The distances h and l are shown there. After sometime, the coin falls into the water, then
Physics-Mechanical Properties of Fluids-78486.png

Physics-Mechanical Properties of Fluids-78486.png

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Both l and h increase
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Both l and h decrease
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l decreases and h increases
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l increases and h decreases

Radius of an air bubble at the bottom of the lake is r and it becomes 2r when the air bubble rises to the top surface of the lake. If p cm of water be the atmospheric pressure, then the depth of the lake is

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2p
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8p
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4p
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7p
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5p

An iceberg is floating in water. The density of ice in the iceberg is 917 kg m^-3 and the density of water is 1024 kg m^-3. What percentage fraction of the iceberg would be visible?

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5%
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10%
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12%
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8%

Two substances of densities ρ₁ and ρ₂ are mixed in equal volume and the relative density of mixture is 4. When they are mixed in equal masses, the relative density of the mixture is 3. The values of ρ₁ and ρ₂ are

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ρ1 = 6 and ρ2 = 2
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ρ1 = 3 and ρ2 = 5
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ρ1 = 12 and ρ2 = 4
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None of these

If the pressure at half of the lake is equal to 1/3 pressure at the bottom of the lake, what is the depth of the lake? (assume, g = 10m/s² , 1 atm =1 × 10⁵ and ρ =10³ kgm^-3)

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9.6 m
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7.5 m
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40 m
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3.2 m

The top surface of an incompressible liquid is open to the atmosphere. The pressure at a depth h₁ below the surface is p₁ . What is the pressure p₂ at depth h₂ = 2h₁ compare with p₁ ?

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p2 > 2p1
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p2 = 2p1
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p2 < 2p1
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p2 = p1

Three liquids of equal masses are taken in three identical cubical vessels A, B and C. Their densities are ρ_A , ρ_B and ρ_C respectively but ρ _A< ρ_B < ρ_C . The force exerted by the liquid on the base of the cubical vessel is

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maximum in vessel C
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minimum in vessel C
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the same in all the vessels
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maximum in vessel A

A wooden ball of density D is immersed in water of density d to a depth h below the surface of water and then released. Upto what height will the ball jump out of water?

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0%
2)
0%
h
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zero

A jar is filled with two non-mixing liquids 1 and 2 having densities ρ₁ and ρ₂ respectively. A solid ball, made of a material of density ρ₃ , is dropped in the jar. It comes to equilibrium in the position shown in the figure. Which of the following is true for ρ₁, ρ₂ and ρ₃ ?
Physics-Mechanical Properties of Fluids-78490.png

Physics-Mechanical Properties of Fluids-78490.png

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ρ3 < ρ1 < ρ2
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ρ1 > ρ3 > ρ2
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ρ1 < ρ2 < ρ3
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ρ1 < ρ3 < ρ2

A liquid X of density 3.36 gcm^-3 is poured in a U-tube, which contains Hg. Another liquid Y is poured in left arm with height 8 cm, upper levels of X and Y are same. What is density of Y?
Physics-Mechanical Properties of Fluids-78491.png

Physics-Mechanical Properties of Fluids-78491.png

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0.8 gcc -1
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1.2 gcc -1
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1.4 gcc -1
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1.6 gcc -1

A solid sphere of volume V and density ρ floats at the interface of two immiscible liquids of densities ρ₁ and ρ₂ respectively. If ρ₁ < ρ < ρ₂, then the ratio of volume of the parts of the sphere in upper and lower liquids is

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2)
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0%

By sucking through a straw, a student can reduce the pressure in his lungs to 750 mm of Hg (density = 13.6 gcm^-3 ). Using the straw, he can drink water from a glass upto a maximum depth of

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10 cm
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75 cm
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13.6 cm
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1.36 cm

From the adjacent figure, the correct observation is
Physics-Mechanical Properties of Fluids-78498.png

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the pressure on the bottom of the tank A is greater than at the bottom of B
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the pressure on the bottom of the tankA is smaller than at the bottom of B
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the pressure depends on the shape of the container
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the pressure on the bottom of A and B is the same

The increases in length in l of a wire of length L by longitudinal stress. Then the stress is proportional to..............

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L/l
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l × L
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l × l
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l2 × L

Physics-Mechanical Properties of Fluids-78500.png

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1.33 mm
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1.33 cm
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2.66 mm
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2.66 cm

Physics-Mechanical Properties of Fluids-78502.png

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0%
2)
0%
0%

Physics-Mechanical Properties of Fluids-78507.png

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0%
2)
0%
0%

If a glass rod is dipped in mercury and withdrawn out, the mercury does not wet the rod because

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Angle of contact is acute
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Cohesion force is more
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Adhesion force is more
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Density of mercury is more

A wire of diameter 1 mm breaks under a tension of 100 N. Another wire of same material as that of the first one, but of diameter 2 mm breaks under a tension of.........