JEE Questions for Physics Mechanical Properties Of Fluids Quiz 15 - MCQExams.com

Work done in increasing the size of a soap bubble from a radius of 3 cm to 5 cm is nearly (Surface tension of soap solution = 0.03 Nm–1)
  • 4 π mJ
  • 0.2 πmJ
  • 2 π mJ
  • 0.4 πmJ
A glass plate is partly dipped vertically in the mercury and the angle of contact is measured. If the plate is inclined , then the angle of contact will
  • Increase
  • Remain unchanged
  • Increase or decrease
  • Decrease
The liquid meniscus in capillary tube will be convex. if the angle of contact is
  • Greater than 90°
  • Less than 90°
  • Equal to 90°
  • Equal to 0°
What is the shape when a non-wetting liquid is placed in a capillary tube
  • Concave upward
  • Convex upward
  • Concave downward
  • Convex downward
When two soap bubbles of radius r1 and r2(r2 > r1) coalesce, the radius of curvature of common surface is

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  • 2)
    Physics-Mechanical Properties of Fluids-79339.png

  • Physics-Mechanical Properties of Fluids-79340.png

  • Physics-Mechanical Properties of Fluids-79341.png
A long cylindrical glass vessel has a small hole of radius r at its bottom. The depth to which the vessel can be lowered vertically in the deep water bath (surface tension T) without any water entering inside is
  • 4T/ρrg
  • 3T/ρrg
  • 2T/ρrg
  • T/ρrg
If the surface tension of a soap solution is 0.03 MKS units, then the excess of pressure inside a soap bubble of diameter 6 mm over the atmospheric pressure will be
  • Less than 40 N/m2
  • Greater than 40 N/m2
  • Less than 20 N/m2
  • Greater than 20 N/m2
The pressure of air in a soap bubble of 0.7cm diameter is 8 mm of water above the pressure outside. The surface tension of the soap solution is
  • 100 dyne/cm
  • 70 dyne/cm
  • 137 dyne/cm
  • 150 dyne/cm
Pressure inside two soap bubbles are 1.01 and 1.02 atmospheres. Ratio between their volumes is
  • 102 : 101
  • (102)3 : (101)3
  • 8 : 1
  • 2 : 1
A capillary tube of radius r is dipped in a liquid of density ρ and surface tension S. If the angle of contact is θ, the pressure difference between the two surfaces in the beaker and capillary

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  • 2)
    Physics-Mechanical Properties of Fluids-79347.png

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  • Physics-Mechanical Properties of Fluids-79349.png
When a large bubble rises from the bottom of a lake to the surface, its radius doubles. If atmospheric pressure is equal to that of column of water height H, then the depth of lake is
  • H
  • 2 H
  • 7 H
  • 8 H
A soap bubble in vacuum has a radius of 3 cm and another soap bubble in vacuum has a radius of 4 cm. If the two bubbles coalesce under isothermal condition, then the radius of the new bubble is
  • 2.3 cm
  • 4.5 cm
  • 5 cm
  • 7 cm
The volume of an air bubble becomes three time as it rises from the bottom of a lake to its surface. Assuming atmospheric pressure to be 75 cm of Hg and the density of water to be 1/10 of the density of mercury, the depth of the lake is
  • 5 m
  • 10 m
  • 15 m
  • 20 m
Excess pressure of one soap bubble is four times more than the other. Then the ratio of volume of first bubble to another one is
  • 1 : 64
  • 1 : 4
  • 64 : 1
  • 1 : 2
There are two liquid drops of different radii. The excess pressure inside over the outside is
  • More in the big drop
  • More in the small drop
  • Equal in both drops
  • There is no excess pressure inside the drops
If the radius of a soap bubble is four times that of another, then the ratio of their pressures will be
  • 1 : 4
  • 4 ; 1
  • 16 : 1
  • 1 : 16
A spherical drop of water has radius 1 mm. If surface tension of water is 70 × 10–3 N/m. Difference of pressures between inside and out side of the spherical drop is
  • 35 N/m2
  • 70 N/m2
  • 140 N/m2
  • Zero
Two bubbles A and B (A > B) are joined through a narrow tube. Then
  • The size of A will increase
  • The size of B will increase
  • The size of B will increase until the pressure equals
  • None of the above
For different capillarities of radii (r), the condition of liquid rise (h) due to surface tension is
  • rh = constant
  • h/r = constant
  • h + r = constant
  • h – r = constant
A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of water in the capillary tube is 5 g Another capillary tube of radius 2r is immersed in water. The mass of water that will rise in this tube is
  • 2.5 g
  • 5.0 g
  • 10 g
  • 20 g
In a capillary tube, water rises to 3 mm. The height of water that will rise in another capillary tube having one-third radius of the first is
  • 1 mm
  • 3 mm
  • 6 mm
  • 9 mm
By inserting a capillary tube upto a depth 1 in water, the water rises to a height h. If the lower end of the capillary is closed inside water and the capillary is taken out and closed end opened, to what height the water will remain in the tube?
  • Zero
  • l + h
  • 2h
  • h
During capillary rise of a liquid in a capillary tube,the surface of contact that remains constant is of
  • Glass and liquid
  • Air and glass
  • Air and liquid
  • All of these
A shell having a hole of radius r is dipped in water. It holds the water upto a depth of h then the value of r is

  • Physics-Mechanical Properties of Fluids-79366.png
  • 2)
    Physics-Mechanical Properties of Fluids-79367.png

  • Physics-Mechanical Properties of Fluids-79368.png
  • None of these
In a capillary tube, water rises by 1.2 mm. The height of water that will rise in another capillary tube having half the radius of the first, is
  • 1.2 mm
  • 2.4 mm
  • 0.6 mm
  • 0.4 mm
Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are 0.8 and 0.6 and surface tension are 60 and 50 dyne/cm respectively. Ratio of heights of liquids in the two tubes h1 /h2 is
  • 10/9
  • 3/10
  • 10/3
  • 9/10
Water rises in a vertical capillary tube upto a height of 2.0 cm. If the tube is inclined at an angle of 60° with the vertical, then upto what length the water will rise in the tube?
  • 2.0 cm
  • 4.0 cm

  • Physics-Mechanical Properties of Fluids-79372.png

  • Physics-Mechanical Properties of Fluids-79373.png
Radius of a capillary is 2 × 10–3m. A liquid of weight 6.28 × 10–4 N may remain in the capillary then the surface tension of liquid will be
  • 5 × 10–3 N/m
  • 5 × 10–2 N/m
  • 5 N/m
  • 50 N/m
Two long capillary tubes A and B of radius RB > RA dipped in same liquid. Then
  • Liquid rise is more in A than B
  • Liquid rises more in B than A
  • Same liquid rise in both
  • All of these according to the density of water
Air is blown through a hole on a closed pipe containing liquid. Then the pressure will
  • Increase on sides
  • Increase downwards
  • Increase in all directions
  • Never increases
A closed rectangular tank is completely filled with water and is accelerated horizontally with an acceleration a towards right. Pressure is (i) maximum at, and (ii) minimum at
Physics-Mechanical Properties of Fluids-79382.png
  • (i) B (ii) D
  • (i) C (ii) D
  • (i) B (ii) C
  • (i) B (ii) A
The density ρ of water of bulk modulus B at a depth y in the ocean is related to the density at surface ρ0 by the relation

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  • 2)
    Physics-Mechanical Properties of Fluids-79385.png

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Why the dam of water reservoir is thick at the bottom
  • Quantity of water increases with depth
  • Density of water increases with depth
  • Pressure of water increases with depth
  • Temperature of water increases with depth
In a hydraulic press the small cylinder has a diameter of ‘d1\' cm, while the large piston has a diameter of \'d2\' cm. If a force ‘F1\' is applied to a small piston, the force on the large piston ‘F2\' is given by

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  • 2)
    Physics-Mechanical Properties of Fluids-79390.png

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A sample of metal weighs 210 g in air, 180 g in water and 120 g in liquid. Then relative density (RD) of
  • Metal is 3
  • Metal is 7
  • Liquid is 3
  • Liquid is 1/3
  • Both (and (3)
A body floats in water with one-third of its volume above the surface of water. If it is placed in oil, it floats with half of its volume above the surface of the oil. The specific gravity of the oil is
  • 5/3
  • 4/3
  • 3/2
  • 1
  • 3/4
A ball whose density is 0.4 × 103 kg/m3 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
Two solids A and B float in water. It is observed that A floats with 1/2 of its body immersed in water and B floats with 1/4 of its volume above the water level. The ratio of the density of A to that of B is
  • 4 : 3
  • 2 : 3
  • 3 : 4
  • 1 : 2
A man is carrying a block of a certain substance (of density 1000 kgm–3) weighing 1 kg in his left hand and a bucket filled with water and weighing 10 kg in his right hand. He drops the block into the bucket. How much load does he carry in his right hand now ?
  • 9 kg
  • 10 kg
  • 11 kg
  • 12 kg
A candle of diameter d is floating on a liquid in a cylindrical container of diameter D [D >> d] as shown in figure. If it is burning at the rate of 2cm/hour then the top of the candle will
Physics-Mechanical Properties of Fluids-79398.png
  • Remain at the same height
  • Fall at the rate of 1 cm/hour
  • Fall at the rate of 2 cm/hour
  • Go up the rate of 1 cm/hour
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water ?

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  • 2)
    Physics-Mechanical Properties of Fluids-79400.png

  • Physics-Mechanical Properties of Fluids-79401.png

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An incompressible liquid flows through a horizontal tube as shown in the following fig. Then the velocity v of the fluid is
Physics-Mechanical Properties of Fluids-79404.png
  • 3.0 m/s
  • 1.5 m/s
  • 1.0 m/s
  • 2.25 m/s
There is a hole in the bottom of tank having water. If total pressure at bottom is 3 atm (1 atm = 105N/m2) then the velocity of water flowing from hole is
  • 20 m/s
  • 2)
    Physics-Mechanical Properties of Fluids-79406.png

  • Physics-Mechanical Properties of Fluids-79407.png
  • None of these
There is a hole of area A at the bottom of cylindrical vessel. Water is filled up to a height h and water flows out in t second. If water is filled to a height 4h, it will flow out in time equal to
  • t
  • 4t
  • 2t
  • t/4
A square plate of 0.1 m side moves parallel to a second plate with a velocity of 0.1 m/s, both plates being immersed in water. If the viscous force is 0.002 N and the coefficient of viscosity is 0.01 poise, distance between the plates in m is
  • 0.1
  • 0.05
  • 0.005
  • 0.0005
A small sphere of mass m is dropped from a great height. After it has fallen 100 m, it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is
  • Greater than the work done by air friction in the second 100 m
  • Less than the work done by air friction in the second 100 m
  • Equal to 100 mg
  • Greater than 100 mg
We have two (narrow) capillary tubes T1 and T2. Their lengths are l1 and l2 and radii of cross-section are r1 and r2 respectively. The rate of flow of water under a pressure difference P through tube T1 is 8 cm3/sec. If l1 = 2l2 and r1 = r2 , what will be the rate of flow when the two tubes are connected in series and pressure difference across the combination is same as before? (= P)
  • 4 cm3/sec
  • (16/cm3/sec
  • (8/cm3/sec
  • None of these
Water is flowing through a horizontal pipe of non-uniform cross-section. At the extreme narrow portion of the pipe, the water will have
  • Maximum speed and least pressure
  • Maximum pressure and least speed
  • Both pressure and speed maximum
  • Both pressure and speed least
A liquid flows in a tube from left to right as shown in figure. A1 and A2 are the cross-sections of the portions of the tube as shown. Then the ratio of speeds v1 /v2 will be
Physics-Mechanical Properties of Fluids-79412.png
  • A1 / A2
  • A2 / A1

  • Physics-Mechanical Properties of Fluids-79413.png

  • Physics-Mechanical Properties of Fluids-79414.png
An application of Bernoulli\'s equation for fluid flow is found in
  • Dynamic lift of an aeroplane
  • Viscosity meter
  • Capillary rise
  • Hydraulic press
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