JEE Questions for Physics Mechanical Properties Of Fluids Quiz 1 - MCQExams.com

Surface tension of water at 1.2 atmospheric pressure
  • More than 74 dynes/cm
  • Less than 74 dynes/cm
  • Same 74 dynes/cm
  • Cannot say
A viscous fluid is flowing through a cylindrical tube. The velocity distribution of the fluid is best represented by the diagram

  • Physics-Mechanical Properties of Fluids-78394.png
  • 2)
    Physics-Mechanical Properties of Fluids-78395.png

  • Physics-Mechanical Properties of Fluids-78396.png
  • None of these
A boat carrying a number of large stones is floating in a water tank. What would happen to the water level, if a few stones are unloaded into water?
  • Rises
  • Falls
  • Remains unchanged
  • Rises till half the number of stones are unloaded and then begins to fall
Two liquid drops have diameters of 1 cm and 1.5 cm. The ratio of excess of pressures inside them is
  • 1 : 1
  • 5 : 3
  • 2 : 3
  • 3 : 2
Water is filled in a container upto height 3m. A small hole of area ‘a’ is punched in the wall of the container at a height 52.5 cm from the bottom. The cross sectional area of the container is A. If a/A = 0.1 then v2 is (where v is the velocity of water coming out of the hole)
  • 50
  • 51
  • 48
  • 51.5
Water rises in plant fibres due to
  • capillarity
  • viscosity
  • fluid pressure
  • osmosis
A liquid does not wet the solid surface if the angle of contact is
  • zero
  • equal to 45°
  • equal to 90°
  • greater than 90°
The meniscus of mercury in a capillary glass tube, is
  • concave
  • plane
  • cylindrical
  • convex
Angle of contact of a liquid with a solid depends on
  • solid only
  • liquid only
  • both on solid and liquid
  • orientation of the solid surface in liquid
For a liquid which is rising in a capillary, the angle of contact is
  • obtuse
  • 180°
  • acute
  • 90°
On the surface of the liquid in equilibrium, molecules of the liquid possess
  • maximum potential energy
  • minimum potential energy
  • maximum kinetic energy
  • minimum kinetic energy
If a big drop of water is broken into smaller drops then the surface energy
  • increases
  • decreases
  • remains unchanged
  • can increase as well as decrease
The potential energy of a molecule on the surface of a liquid compared to one inside the liquid is
  • zero
  • lesser
  • equal
  • greater
Surface tension vanishes at
  • absolute zero temperature
  • transition temperature
  • critical temperature
  • None of the above
Which one of the following equation is Torricelli\'s law?
  • p = ρgh
  • 2)
    Physics-Mechanical Properties of Fluids-78368.png
  • ηRe = ρvd
  • S ( 2d l ) = Fd
The terminal velocity of spherical ball of radius a falling through a viscous liquid is proportional to
  • a
  • a2
  • a3
  • a-1
Streamline flow is more likely for liquids with
  • high density and low viscosity
  • low density and high viscosity
  • high density and high viscosity
  • low density and low viscosity
Bernoulli's theorem is a consequence of the law of conservation of
  • momentum
  • mass
  • energy
  • angular momentum
At what speed, the velocity head of water is equal to pressure head of 40 cm of Hg?
  • 10.3 ms -1
  • 2.8 ms -1
  • 5.6 ms -1
  • 8.4 ms -1
A steel ball is dropped in oil, then
  • the ball attains constant velocity after sometime
  • the ball stops
  • the speed of ball will keep on increasing
  • None of the above
Water falls from a tap, down the streamline
  • area decreases
  • area increases
  • velocity remains same
  • area remains same
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 figure. Just after opening the valve,
Physics-Mechanical Properties of Fluids-78370.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 changes occurs
  • air from end 2 flows towards end 1. volume of the soap bubble at end 1 increases
The flow of liquid is laminar or stream line is determined by
  • rate of flow of liquid
  • density of fluid
  • radius of the tube
  • coefficient of viscosity of liquid
In streamline flow of liquid, the total energy of liquid is constant at
  • all points
  • inner points
  • outer points
  • None of these
A body weighs 50 g in air and 40 g in water. How much would it weigh in a liquid of specific gravity 1.5?
  • 30 g
  • 35 g
  • 65 g
  • 45 g
A piece of wood is floating in water. When the temperature of water rises, the apparent weight of the wood will
  • increase
  • decrease
  • may increase or decrease
  • remain same

Physics-Mechanical Properties of Fluids-78371.png

  • Physics-Mechanical Properties of Fluids-78372.png
  • 2)
    Physics-Mechanical Properties of Fluids-78373.png

  • Physics-Mechanical Properties of Fluids-78374.png

  • Physics-Mechanical Properties of Fluids-78375.png
One end of a horizontal thick copper wire of length 2L and radius 2R is welded to an end of another horizontal thin copper wire of length L and radius R. When the arrangement is stretched by applying forces at two ends, the ratio of the elongation in the thin wire to that in the thick wire is
  • 0.25
  • 0.50
  • 2.00
  • 4.00
The excess pressure inside a spherical drop of water is four times that of another drop. Then their respective mass ratio is
  • 1 : 16
  • 8 : 1
  • 1 : 4
  • 1 : 64
  • 32 : 1
The excess pressure inside one soap bubble is three times that inside a second soap bubble, then the ratio of their surface areas is
  • 1 : 9
  • 1 : 3
  • 3 : 1
  • 1 : 27
  • 9 : 1
A spherical drop of water has radius 1 mm if surface tension of water is 70 × 10-3 Nm-1, difference of pressure between inside and outside of the spherical drop is
  • 35 Nm -2
  • 70 Nm -2
  • 140 Nm -2
  • zero
The excess pressure in a bubble of radius R of a gas in a liquid of surface tension S is

  • Physics-Mechanical Properties of Fluids-78378.png
  • 2)
    Physics-Mechanical Properties of Fluids-78379.png

  • Physics-Mechanical Properties of Fluids-78380.png

  • Physics-Mechanical Properties of Fluids-78381.png
The excess of pressure inside the first soap bubble is three times that inside the second bubble. The ratio of volume of the first to that of the second bubble is
  • 9 : 1
  • 1 : 3
  • 1 : 9
  • 1 : 27
A soap bubble A of radius 0.03 m and another bubble B of radius 0.04 m are brought together so that the combined bubble has a common interface of radius r, then the value of r is
  • 0.24 m
  • 0.48 m
  • 0.12 m
  • None of these
There is a small bubble at one end and bigger bubble at other end of a rod. What will happen?
  • Smaller will grow until they collapse
  • Bigger will grow until they collapse
  • Remain in equilibrium
  • None of the above
If two soap bubbles of equal radii r coalesce, then the radius of curvature of interface between two bubbles will be
  • r
  • zero
  • infinity
  • 1/2r
A glass capillary of radius 0.4 mm is inclined at 60° with the vertical in water. Find the length of water in the capillary tube. (surface tension of water = 7 × 10-2 N / m).
  • 7.1 cm
  • 3.6 cm
  • 1.8 cm
  • 0.9 cm
If the rise in height of capillary of two tubes are 6.6 cm and 2.2 cm, then the ratio of the radii of tubes is
  • 1 : 3
  • 3 : 1
  • 1 : 2
  • 1 : 6
If the length of tube is less and cannot accommodate the maximum rise of liquid, then
  • liquid will form fountain
  • liquid will not rise
  • the meniscus will adjust itself so that the water does not spill
  • None of the above
The work done in blowing a soap bubble of surface tension 0.06 Nm-1 from 2 cm radius to 5 cm radius is
  • 0.004168 J
  • 0.003168 J
  • 0.003158 J
  • 0.004568 J
Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to smaller one?
  • 21/2 : 1
  • 1 : 1
  • 22/3 : 1
  • None of these
Energy of bubble is E. If one thousand such bubbles coalesce to form a large bubble then its energy is E1, then ratio E and E1 is equal to

  • Physics-Mechanical Properties of Fluids-78382.png
  • 2)
    Physics-Mechanical Properties of Fluids-78383.png

  • Physics-Mechanical Properties of Fluids-78384.png

  • Physics-Mechanical Properties of Fluids-78385.png
Two mercury drops (each of radius r) merge to form a bigger drop. The surface energy of the bigger drop, if T is the surface tension, is
  • 25/3π r2T
  • 4π r2T
  • 2π r2T
  • 28/3π r2T
Determine the energy stored in the surface of a soap bubble of radius 2.1 cm if its surface tension is 4.5 × 10-2 Nm-1.
  • 8 mJ
  • 2.46 mJ
  • 4.93 ×10-4 J
  • None of these
With an increase in temperature, surface tension of liquid (except molten copper and cadmium)
  • increases
  • remain same
  • decreases
  • first decreases then increases
The surface tension of soap solution is 0.03 Nm-1. The work done in blowing to form a soap bubble of surface area 40 cm2 , (in J), is
  • 1.2 × 10 -4
  • 2.4 × 10 -4
  • 12 × 10 -4
  • 24 × 10 -4
One drop of soap bubble of diameter D breakes into 27 drops having surface tension T. The change in surface energy is
  • 2πTD2
  • 4πTD2
  • πTD2
  • 8πTD2
A drop of oil is placed on the surface of water then it will spread as a thin layer, because
  • surface tension tends to give the oil a spherical surface
  • surface tension of water is greater than that of oil
  • both oil and water have nearly equal surface tension
  • oil is lighter than water
A beaker of radius 15 cm is filled with a liquid of surface tension 0.75 Nm -1. Force across an imaginary diameter on the surface of the liquid is
  • 0.075 N
  • 1.5 × 10 -2 N
  • 0.225 N
  • 2.25 × 10 -2 N

Physics-Mechanical Properties of Fluids-78390.png
  • 1.55 × 105 Pa
  • 0.115 × 105 Pa
  • 1.4 × 105 Pa
  • 1.01 × 105 Pa
0:0:1


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