JEE Questions for Physics Mechanical Properties Of Fluids Quiz 2 - MCQExams.com

A square wire frame of size L is dipped in a liquid. On taking out a membrane is formed. If the surface tension of liquid is T, then force acting on a frame will be
  • 2T/L
  • 4T/L
  • 8TL
  • 16T/L
Work done in forming a liquid drop of radius R is W1 and that of radius 3R is W2 . The ratio of work done is
  • 1 : 3
  • 1 : 2
  • 1 : 4
  • 1 : 9
The surface tension of a liquid is 5 Nm-1. If a film is held on a ring of area 0.02 m2, its total surface energy is about
  • 2 × 10 -2 J
  • 2.5 × 10 -3 J
  • 2 × 10 -1 J
  • 3 × 10 -1 J
Two rain drops reach the earth with different terminal velocities having ratio 9 : 4. Then, the ratio of their volumes is
  • 3 : 2
  • 4 : 9
  • 9 : 4
  • 27 : 8
In a turbulent flow, the velocity of the liquid in contact with the walls of the tube is
  • zero
  • maximum
  • in between zero and maximum
  • equal to critical velocity
Water is moving with a speed of 5.18 ms -1 through a pipe with a cross-sectional area of 4.20 cm2. The water gradually descends 9.66 m as the pipe increase in area to 7.60 cm2. The speed of flow at the lower level is
  • 3.0 ms -1
  • 5.7 ms -1
  • 3.82 ms -1
  • 2.86 ms -1
A river of salty water is flowing with a velocity 2 ms -1. If the density of the water is 1.2 gcc -1, then the kinetic energy of each cubic metre of water is
  • 2.4 J
  • 24 J
  • 2.4 KJ
  • 4.8 KJ
A rectangular vessel when full of water, takes 10 min to be emptied through an orifice in its bottom. How much time will it take to be emptied when half filled with water?
  • 9 min
  • 7 min
  • 5 min
  • 3 min
An air bubble of radius 10-2 m is rising up at a steady rate of 2 × 10-3 ms-1 through a liquid of density 1.5 × 103 kg m-3, the coefficient of viscosity neglecting the density of air, will be (take, g = 10 ms-2)
  • 23.2 units
  • 83.5 units
  • 334 units
  • 167 units
A metal plate of area 103 cm2 rests on a layer of oil 6 mm thick. A tangential force of 10-2 N is applied on it to move it with a constant velocity of 6 cms-1. The coefficient of viscosity of the liquid is
  • 0.01 poise
  • 0.5 poise
  • 0.7 poise
  • 0.9 poise
A cylinder of height 20 m is completely filled with water. The velocity of efflux of water (in ms-1) through a hole on the side wall of the cylinder near its bottom, is
  • 10
  • 20
  • 25.5
  • 5
Water is flowing through a pipe of constant cross-section. At some point the pipe becomes narrow and the cross-section is halved. The speed of water is
  • reduced to zero
  • decreased by a factor of 2
  • increased by a factor of 2
  • unchanged
An iron sphere of mass 20 × 10-3 kg falls through a viscous liquid with terminal velocity 0.5 ms-1 . The terminal velocity (in ms-1) of another iron sphere of mass 54 × 10-2 kg is
  • 4.5
  • 3.5
  • 2.5
  • 1.5
Ice pieces are floating in a beaker A containing water and also in a beaker B containing miscible liquid of specific gravity 1.2. When ice melts, the level of
  • water increases in A
  • water decreases in A
  • liquid in B decreases
  • liquid in B increases
  • water in A and liquid in B remains unaltered
Two solid pieces, one of steel and the other of aluminium when immersed completely in water have equal weights. When the solid pieces are weighed in air
  • the weight of aluminium is half the weight of steel
  • steel piece will weigh more
  • they have the same weight
  • aluminium piece will weigh more
A body floats in a liquid contained in a beaker. If the whole system falls under gravity, then the upthrust on the body due to liquid is
  • equal to the weight of the body in air
  • equal to the weight of the body in liquid
  • zero
  • equal to the weight of the immersed part of the body
A vessel contains oil (density 0.8 gcm-3) over mercury (density 13.6 gcm-3 ). A homogeneous sphere floats with half volume immersed in mercury and the other half in oil. The density of the material of the sphere in gcm-3 is
  • 12.8
  • 7.2
  • 6.4
  • 3.3
If there were no gravity, which of the following will not be there for a fluid?
  • Viscosity
  • Surface tension
  • Pressure
  • Archimedes' upward thrust
A ball whose density is 0.4 × 103 kg m-3 falls into water from a height of 9 cm. To what depth does the ball sink?
  • 9 cm
  • 6 cm
  • 4.5 cm
  • 2.25 cm
At a given place where acceleration due to gravity is gms-2, a sphere of lead of density d kgm-3 is gently released in a column of liquid of density ρ kgm-3. If d > ρ, the sphere will
  • fall vertically with an acceleration gms -2
  • fall vertically with no acceleration
  • fall vertically with an acceleration
    Physics-Mechanical Properties of Fluids-78399.png
  • fall vertically with an acceleration
    Physics-Mechanical Properties of Fluids-78400.png
A glass flask having mass 390 g and an interior volume of 500 cm3 floats on water when it is less than half–filled with water. The density of the material of the flask is
  • 0.8 gcc -1
  • 2.8 gcc -1
  • 1.8 gcc -1
  • 0.28 gcc -1
Radius of one arm of hydraulic lift is four times of radius of other arm. What force should be applied on narrow arm to lift 100 kg?
  • 26.5 N
  • 62.5 N
  • 6.25 N
  • 8.3 N
A rectangular block is 5 cm × 5 cm × 10 cm in size. The block is floating in water with 5 cm side vertical. If it floats with 10 cm side vertical, what change will occur in the level of water?
  • It will fall
  • No change
  • It will rise
  • It may rise or fall depending on the density of block
The neck and bottom of a bottle are 3 cm and 15 cm in radius respectively. If the cork is pressed with a force 12 N in the neck of the bottle, then force exerted on the bottom of the bottle is
  • 30 N
  • 150 N
  • 300 N
  • 600 N
A body floats in water with 40% of its volume outside water. When the same body floats in an oil, 60% of its volume remains outside oil. The relative density of oil is
  • 0.9
  • 1.0
  • 1.2
  • 1.5
An object weighs m1 in a liquid of density d1 and that in liquid of density d2 is m2.
The density d of the object is

  • Physics-Mechanical Properties of Fluids-78403.png
  • 2)
    Physics-Mechanical Properties of Fluids-78404.png

  • Physics-Mechanical Properties of Fluids-78405.png

  • Physics-Mechanical Properties of Fluids-78406.png
An open U-tube contains mercury. When 11.2 cm of water is poured into one of the arms of the tube, how high does the mercury rise in the other arm from its initial unit?
  • 0.56 cm
  • 1.35 cm
  • 0.41 cm
  • 2.32 cm
A piece of solid weighs 120 g in air, 80 g in water and 60 g in a liquid. The relative density of the solid and that of the liquid are respectively.
  • 3, 2
  • 2, 3/4
  • 3/2, 2
  • 4, 3
  • 3, 3/2
The temperature at which the vapour pressure of a liquid becomes equals of the external pressure is its.
  • Melting point
  • sublimation point
  • Critical temprature
  • Boiling point
Assertion (A) The upper surface of the wings of an aeroplane is made convex and the lower surface is made concave.
Reason (R) The air currents at the top have a smaller velocity and thus less pressure at the bottom than at the top.
  • Both A and R are correct and R is the correct explanation of A
  • Both A and R are correct but R is not a correct explanation of A
  • A is correct but R is incorrect
  • A is incorrect but A is correct
A glass tube of uniform internal radius r has a valve separating the two identical ends. Initially, the valve is in a tightly closed position. End 1 has a hemispherical soap bubble of radius r .End 2 has sub hemispherical soap bubble as shown in the figure.
Physics-Mechanical Properties of Fluids-78408.png
  • air from end 1 flows towards end 2. No change in the volume of the soap bubbles
  • air from end 1 flows towards end 2. Volume of the soap bubble at end 1 decreases
  • no change occurs
  • air from end 2 flows towards end 1. Volume of the soap bubble at end 1 increases
A thread is tied slightly loose to a wire frame as in figure and the frame is dipped into a soap solution and taken out. The frame is completely covered with the film. When the portion A is punctured with a pin, the thread
Physics-Mechanical Properties of Fluids-78409.png
  • becomes concave towards A
  • becomes convex towards A
  • either (a) or (b) depending on the size of A w.r.t. B
  • remains in the initial position
Three capillaries of length L, L/2 and L/3 are connected in series. Their radii are r, r/2 and r/3 respectively. Then, if streamline flow is to be maintained and the pressure across the first capillary is p, then the
  • pressure difference across the ends of second capillary is 8p
  • pressure difference across the third capillary is 43p
  • pressure difference across the ends of the second capillary is 16p
  • pressure difference across the third capillary is 56p
A 20 cm long capillary tube is dipped in water. The water rises upto 8 cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be
  • 8 cm
  • 10 cm
  • 4 cm
  • 20 cm
The heat evolved for the rise of water when one end of the capillary tube of radius r is immersed vertically into water is (assume, surface tension = T and density of water = ρ )

  • Physics-Mechanical Properties of Fluids-78411.png
  • 2)
    Physics-Mechanical Properties of Fluids-78412.png

  • Physics-Mechanical Properties of Fluids-78413.png
  • None of these
Several spherical drops of a liquid of radius r coalesce to form a single drop to radius R. If T is surface tension and V is volume under consideration, then the release of energy is

  • Physics-Mechanical Properties of Fluids-78414.png
  • 2)
    Physics-Mechanical Properties of Fluids-78415.png

  • Physics-Mechanical Properties of Fluids-78416.png

  • Physics-Mechanical Properties of Fluids-78417.png
When a big drop of water is formed from n small drops of water, the energy loss is 3E, where E is the energy of the bigger drop. If R is the radius of the bigger drop and r is the radius of the smaller drop, then number of smaller drops (n)is

  • Physics-Mechanical Properties of Fluids-78418.png
  • 2)
    Physics-Mechanical Properties of Fluids-78419.png

  • Physics-Mechanical Properties of Fluids-78420.png

  • Physics-Mechanical Properties of Fluids-78421.png
Assume that a drop of liquid evaporates by decrease in its surface energy, so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible?
The surface tension is T, density of liquid is ρ and L is its latent heat of vaporisation
  • ρL/T
  • 2)
    Physics-Mechanical Properties of Fluids-78422.png
  • T/ρL
  • 2T/ρL
A mercury drop of radius 1.0 cm is sprayed into 106 droplets of equal sizes. The energy expended in this process is (surface tension of mercury is equal to 32 × 10-2 Nm-1)
  • 3.98 ×10-4 J
  • 8.46 × 10-4 J
  • 3.98 × 10-2 J
  • 8.46 × 10-2 J

Physics-Mechanical Properties of Fluids-78424.png
  • 4
  • 6
  • 7
  • 8
The excess pressure inside a spherical drop of radius r of a liquid of surface tension T is
  • directly proportional to r and inversely proportional to T
  • directly proportional to T and inversely proportional to r
  • directly proportional to the product of T and r
  • inversely proportional to the product of T and r
Soap bubbles can be formed floating in air by blowing soap solution in air, with the help of a glass tube but not water bubbles. It is because
  • the excess pressure inside water bubble being more due to large surface tension
  • the excess pressure inside water bubble being less due to large surface tension
  • the excess pressure inside water bubble being more due to large viscosity
  • the excess pressure inside water bubble being less due to less viscosity
A frame made of metallic wire enclosing a surface area A is covered with a soap film. If the area of the frame of metallic wire is reduced by 50%, the energy of the soap film will be changed by
  • 100%
  • 75%
  • 50%
  • 25%
A steel ring of radius r and cross–section area 'A' is fitted on to a wooden disc of radius R(R > r ) If young's modulus be E then what is force with which the steel ring is expanded ?

  • Physics-Mechanical Properties of Fluids-78512.png
  • 2)
    Physics-Mechanical Properties of Fluids-78513.png

  • Physics-Mechanical Properties of Fluids-78514.png

  • Physics-Mechanical Properties of Fluids-78515.png
A vessel whose bottom has round hole with diameter of 1 mm is filled with water. Assuming that surface tension acts only at hole, then the maximum height to which the water can be filled in vessel without leakage is (surface tension of water = 7.5 ×10-2 Nm-1 and g =10 ms -2)
  • 0.3 cm
  • 3 mm
  • 3 cm
  • 3 m
Two soap bubbles combine to form a single bubble. In this process, the change in volume and surface area are respectively V and A. If p is the atmospheric pressure and T is the surface tension of the soap solution,then which of the following relation is true?
  • 4pV + 3TA = 0
  • 3pV – 4TA = 0
  • 4pV – 3TA = 0
  • 3pV + 4TA = 0
A rain drop of radius 0.3 mm has a terminal velocity of 1 ms-1 in air. The viscosity of air is 18 ×10-5 poise. The viscous force on the drop will be
  • 16.95 ×10-9 N
  • 1.695 ×10-9 N
  • 10.17 ×10-9 N
  • 101.73 ×10-9 N

Physics-Mechanical Properties of Fluids-78427.png
  • 0.5 m
  • 1 m
  • 1.5 m
  • 2.2 m
If a ball of steel (density ρ = 7.8 g cm-3) attains a terminal velocity of 10 cm s-1 when falling in a tank of water (coefficient of viscosity ηwater = 8.5 × 10-4 Pa-s) then its terminal velocity in glycerine (ρ =1.2 g cm-3, η = 13.2 Pa-s) would be nearly
  • 1.6 ×10-5 cms-1
  • 6.25 ×10-4 cms-1
  • 6.45 ×10-4 cms-1
  • 1.5 ×10-5 cms-1
Water is flowing continuously from a tap having an internal diameter 8 × 10-3 m. The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance 2 ×10-1 m below the tap is close to
  • 7.5 × 10-3 m
  • 9.6 × 10-3 m
  • 3.6 × 10-3 m
  • 5.0 × 10-3 m
0:0:1


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