Fluid Statics and Dynamics (1)

5/28/2018 Fluid Statics and Dynamics (1)

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Note: Please read the Important Instructions and Disclaimer file before

solving the MCQs

4. FLUID STATICS AND DYNAMICS

1) The rain drops are in spherical shape due toA) Viscosity

B) Surface tensionC) thrust on drop

D) residual pressure

2) An iron needle floats on the surface of water. This phenomenon is attributed toA) upthrust of liquid

B) ViscosityC) surface tension

D) gravitational forces

3) The excess pressure across the surface of a soap bubble of radius r(with as thesurface tension of soap solution)is

A) A) r/

B) 2 r/

C) 4 r/

D) 8 r/

4) Two soap bubbles are blown simultaneously .In the first soap bubble, the excesspressure is 4 times of second soap bubble. The ratio of radii of first to second

soap bubble isA) 1:4

B) 2:1C) 1:2

D) 4:1

5) The property utilized in the manufacture of lead shots isA) specific weight of liquid lead

B) compressibility of liquid lead

C) specific gravity of liquid leadD) surface tension of liquid lead


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6) A block of volume V and of density bis placed in a liquid of density l ( l >

b), then block is moved upward due to buoyant force to a height h. The increase

in potential energy is

A) bVghB) ( b+ l) VghC) ( b- l) Vgh

D) Zero

7) Two small drops of mercury, each of radius r, form a single large drop. The ratioof surface energy before and after this change is

A) 1:21/3

B) 21/3:1

C) C ) 2:1D) 1:2

8) A wooden block is taken to the bottom of a deep, calm lake of water and then

released. It rises up with aA) constant acceleration

B) decreasing accelerationC) constant velocity

D) decreasing velocity

9) A man in a lift is holding a can filled with water but having a hole in its bottom.When will the drainage of water be maximum?

A) When the lift is going up with acceleration

B) when the lift is going down with accelerationC) When the lift is stationaryD) when the lift goes down with uniform velocity

10) In old age, arteries carrying blood in the human body, become narrow resulting in

an increase in the blood pressure. This follows fromA) Pascals law

B) Stokes lawC) Bernoullis principle

D) Archimedes principle

11) Soap helps in better cleansing of clothes because

A) it reduces the surface tension of solutionB) it does not reduce the surface tension of solution

C) it absorbs the dirtD) chemicals of soap change


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12) If two soap bubbles of different radii are in communication with each otherA) air flows from the larger bubble into the smaller one until the two bubbles

are of equal size

B) the sizes of the bubbles remain unchangedC) air flows from the smaller bubble into the larger one and large bubble

grows at the expense of the smaller one

D) air flows from the larger into the smaller bubble until the radius of thesmaller one becomes half that of the larger one

13) More liquid rises in a thin tube because of

A) larger value of radiusB) larger value of surface tension

C) smaller value of S.TD) smaller value of radius

14) The surface tension of soap solution is 25x10-3Nm

-1. The excess pressure inside a

soap bubble of diameter 1 cm isA) 10 Pa

B) 20 PaC) 5 Pa

D) 15 Pa

15) Water rises in a capillary tube to a certain height such that the upward force due tosurface tension is balanced by 75 10

-4N force due to weight of the liquid. If the

surface tension of water is 6 10-2

Nm-1

, the inner circumference of the capillary

must beA) 1.25 10

-2m

B) 0.50 10-2m

C) 6.5 10-2

mD) 12.5 10

-2m

16) When a soap bubble is charged

A) it contractsB) it expands

C) it does not undergo any change in sizeD) it disappears

17) A drop of oil is placed on the surface of water. Which of the following statements

is correct?A) it will remain on it as a sphere

B) it will spread as a thin layerC) it will partly changed to spherical droplets and partly as thin film

D) it will float as a distorted drop on the water surface


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18) Small droplets of liquid are usually more spherical in shape than larger drops ofthe same liquid because

A) force of surface tension is equal and opposite to the force of gravity

B) force of surface tension predominates the force of gravityC) force of gravity predominates the force of surface tensionD) force of gravity and force of surface tension act in the same direction and

are equal

19) Water rises to a height of 16.3 cm in a capillary of height 18 cm above the waterlevel. If the tube is suddenly cut at a height of 12 cm

A) water will come as a fountain from the capillary tubeB) water will stay at a height of 12 cm in the capillary tube

C) the height of the water in the capillary will be 10.3 cmD) water will flow down the sides of the capillary tube

20) A soap bubble has radius r and the surface tension of the soap film is T . The

energy needed to double the diameter of the bubble without change oftemperature is

A) 4 r2T

B) 2 r2T

C) 12 r2T

D) 24 r2T

21) A hollow sphere has a small hole in it. On lowering the sphere in a tank of water

to a depth of 40 cm below the surface it is observed that water enters into thehollow sphere. Surface tension of water is 7 10-3Nm-1. The diameter of the hole

isA) 1/7 mm

B) 1/14 mmC) 1/21 mm

D) 1/28 mm

22) A liquid drop of radius R is broken up into N small droplets. The work done isproportional to

A) NB) B N-2/3

C) C. N-1/3D) D. N

-0.5


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23) An air bubble of radius r is formed inside a tank of water of depth h. Theatmospheric pressure is equal to a water column of height H. the pressure inside

the bubble is

A) A.H + hB) H + h + 2T/rC) H + h + 4T/r

D) H + h + T/r(T is surface tension of water)

24) A liquid film is formed over a frame ABCD as shown in the figure. Wire CD can

slide without friction. The mass to be hung from CD to keep it in equilibrium is

A) Tl/g

B) .2Tl/gC) 4Tl/g

D) T l

25) It is easier to spray water to which soap is added, becauseA) addition of soap to water decreases surface tension of water

B) addition of soap to water increases surface tension of waterC) addition of soap to water makes surface tension of water zero

D) addition of soap to water increases its density

26) A capillary tube remains dipped in a water container, so that loss in weight of thecapillary tube is

A) equal to the upward buoyant forceB) less than the upward buoyant forceC) more than the upward buoyant force

D) half of the buoyant force


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27) One thousand small water droplets of equal size combine to form a big drop. Theratio of the final surface energy to the total initial surface energy is

A) 10:1

B) 1:10C) 1000:1D) 1:1000

28) The unit of surface tension in M.K.S units is given by

A) Dynes per cm2

B) dynes per cm

C) Newtons per meterD) Newtons per metre2

29) What will be the height of a liquid column in a capillary tube on the surface of

the moon?A) six times that on earth's surface

B) 1/6th of what was on earth's surfaceC) it will remain unchanged

D) zero

30) Two match sticks are laid side by side on the surface of water. When a drop oflight oil on the end of a third match stick is touched to the surface film between

the two floating sticks , the two match sticksA) will move apart rapidly

B) will remain as they are

C) will come closerD) will be joined

31) A water drop of radius 1 mm is broken into 106equal droplets. How much work is

done in it if the temperature remains constant? Surface tension of water = 0.072

J/m2A) 8.95 10

-3J

B) 8.95 10-5

JC) 8.95 10

-7J

D) 8.95 10-9

J

32) Soldering of two metals possible because of the property ofA) viscosity

B) surface tensionC) osmosis

D) cohesion


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33) When the adhesive force in the case of liquid and glass is greater than thecohesive forces between the liquid molecules, the shape of the meniscus of liquid

in a capillary tube is

A) PlaneB) concaveC) Convex

D) circular

34) S.T of water is 5 N/m. If a film is formed on a ring of area 0.02 m2, then its

surface energy is

A) 5 10-2joule

B) 2.5 10-2joule

C) 2 10-1

jouleD) 3 10

-1joule

35) If the work done in blowing a bubble of volume V is W, then the work done inblowing a soap bubble of volume 2V will be

A) WB) 2W

C) W2

D) 3 4W

36) The pressure inside two soap bubbles is 1.01 and 1.02 atmosphere respectively.

The ratio of their volumes isA) 102:101

B) (102)3: (101)3

C) 8:1

D) 2:1

37) The surface tension of soap is 0.475 10-2

N/m . The work done in blowing asoap bubble of radius 2.0 cm is

A) 7.6 10-6

jouleB) 15.2 10

-6 joule

C) 1.9 10-6

joule

D)

D )1 10

-4

joule

38) A soap bubble of diameter 8 cm is formed in air. The surface tension of liquid is

30 dyne/cm. The excess pressure inside the soap bubble isA) 150 dyne/cm

2

B) 30.0 dyne/cm2

C) 3 10-3

dyne/cm2

D) 12 dyne/cm2


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39) Two tubes of the same material but of different radii are dipped in a liquid. The

height to which a liquid rises in one tube is 2.2cm and in the other is 6.6 cm. The

ratio of their radii isA) 9 :1B) 1:9

C) 3:1D) 1:3

40) A large air bubble of radius r rises from the bottom of a lake to the surface. The

depth of the lake is 7H. If the atmospheric pressure is equal to that of water ofheight H, the radius of the bubble is

A) rB) 2 r

C) 3 rD) 8 r

41) A raft of wood of density 600kg/m3and mass 120 kg floats in water. How much

weight can be put on the raft to make it just sink?A) 200kg

B) 40kgC) 120kg

D) 80kg

42) If a block of iron (density 5gm/cm3) of size 5 cm 5 cm 5 cm was weighed

whilst completely submerged in water, what would have been its apparentweight?(density of water = 1 gm/cm3)

A) 5 5 5 5gmB) 4 4 4 5 gm

C) 3 5 5 5 gmD) 4 5 5 5 gm

43) A boy is carrying a bucket of water in one hand with a 0.05 kg cork piece in it.

After sometime he takes out the cork piece and holds it in the other hand. Theboy will carry

A) more load than beforeB) less load than before

C) same load as beforeD) Either less or more load depending on the density of plastic.


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44) A beaker is partly filled with water, the beaker and the contents have a mass of 50gm. A piece of wood having a volume of 5 cc. is floated in the beaker. The

density of wood is 0.8 g/cc. the mass of the beaker and its contents is

A) 50 gB) 54gC) 46 g

D) 56.25 g

45) A bird, resting on the floor of an airtight box, which is being carried by a boy,starts flying. The boy will feel that the box

A) is now heavierB) is now lighter

C) shows no change in weightD) lighter in the beginning and heavier afterwards

46) A cube of size 10 cm is floating in equilibrium in a tank of water. When a mass of

10 gm is placed on the cube, the depth of the cube inside the water increases by(g = 10 ms-2density of water = 103 kg m-3)

A) 0.1 mmB) 1mm

C) 1 cmD) 0.1 m

47) A wooden cube just floats inside water when a 200gm mass is placed on it. When

the mass is removed, the cube is 2 cm above the water level. The size of the cube

isA) 5 cmB) 10 cm

C) 15 cmD) 20 cm

48) Pressure applied to an enclosed fluid is

A) increased and applied to every part of the fluidB) diminished and transmitted to the wall of the container

C) increased in proportion to the mass of the fluid and then transmittedD) transmitted unchanged to every portion of the fluid and walls of the

containing vessel.

49) A parrot is in a wire case, which is hanging from a spring balance. Initiallythe parrot sits in the cage and in the second instant the parrot flies inside the cage

A) the reading of the balance will be greater when the parrot files in the cageB) the reading of the balance will be lesser when the parrot files in the cage

C) the reading will remain unchangedD) None of the above


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50) If there would be smaller gravitational effects, which of the following forces do

you think would alter in some respect?

A) Viscous forcesB) Buoyant forcesC) Nuclear forces

D) Electrostatic forces

51) Two stretched membrances of area 2m2and 3m

2are placed in a liquid at the same

depth. The ratio of the pressures on them is

A) 1 : 1B) 2 : 3

C) 2 : 3

D)

2

2

: 3

2

52) If you float on your back on water, your weight isA) Zero

B) equal to your normal weightC) half to your normal weight

D) greater than the weight of water you displace

53) The height of mercury column in a simple barometer is h. As tube is inclined to

the vertical at an angle . The length of the mercury column along the length of

the tube is l,then

A)

1= hB) 1= h/cos

C) 1= h cos

D) 1 = h sin

54) Find the lifting force of a 4 kg cork life belt in sea water if the density of cork andsea water are 0.2 10

3kg/m

3and 1.03 10

3kg/m

3respectively.

A) 163 NB) 273 N

C) 119 ND) 289 N

55) A cylindrical vessel is filled with equal mass of mercury and water. The over all

height of the two layers is 43.8 cm. Relative density of mercury is 13.6. Then thepressure of the liquid on the bottom of the vessel is

A) 3 cm of HgB) 6 cm of Hg

C) 1.5 cm of HgD) 16.6 cm of Hg


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56) Two bodies are in equilibrium when suspended in water from the arms of a

balance. The mass of one body is 36 gm and its density is 9 gm/cc. If the mass of

the other is 48 gm, its density in gm/cc isA) 4/3B) 3/2

C) 3D) 5

57) Three liquids of densities d, 2d and 3 d are mixed in equal volumes. Then the

density of mixture isA) d

B) 2dC) 3d

D) 5d

58) Three liquids of densities d, 2d and 3d are mixed in equals proportions of weights.The relative density of the mixture is

A) 11/7dB) 18/11d

C) 13/9dD) 23/18d

59) A piece of metal of specific gravity 3.4 floats in mercury of specific gravity 13.6.

What fraction of its volume is under mercury?

A) 0.25B) 0.50C) 0.75

D) 0.80

60) A capillary tube of radius r is placed in a liquid. If the angle of contact is , the

radius of curvature R of the meniscus in the capillary is

A) rB) r sin

C)cos

r

D) r cos


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61) Water flows steadily through a horizontal pipe of a variable cross-section. If the

pressure of water is P at a point where the velocity of flow is , what is the

pressure at another point where the velocity of flow is 2; being the density of

water?

A) P-2

3

2

B) P +2

3

2

C) P -22

D) P + 22

62) The cylindrical tube of a spray pump has a radius R, one end of which has n fine

holes, each of radius r. If the speed of flow of the liquid in the tube is V, the speedof ejection of the liquid through the holes is

A)n

V

2/1

r

R

B)n

V

r

R

C)n

V

2/3

r

R

D) n

V

2

r

R

63) In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the

lower and upper surfaces of the wings are and 2 respectively. If the

density of air is and the surface area of the wings is A, the dynamic lift on the

wing is given by

A)2

12A

B)A2

2

1

C) 2 2A

D) 22A


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64) Water is flowing through a tube of radius r with a speed . If this tube is joined to

another tube of radius r/2, what is the speed of water in the second tube?

A) 4

B)2

C) 2

D) 4

65) A liquid flows through a pipe of varying diameter. The velocity of the liquid is

2ms-1

at a point where the diameter is 6cm. The velocity of the liquid at a pointwhere the diameter is 3 cm will be

A) 1 ms-1

B)

4ms

-1

C) 8ms-1D) 16ms

-1

66) Which one of the following statements is correct for a fluid passing through the

narrow part of non-uniform pipe.A) its velocity and pressure both increase

B) its velocity and pressure both decreaseC) its velocity decreases but its pressure increases

D) its velocity increases but its pressure decreases

67) Water from a tap emerges vertically downwards with an initial speed of 1.0 ms-1.The cross-sectional area of tap is 10-4m2. Assume that the pressure is constant

throughout the stream of the water and that the flow is steady. The cross sectional area of the stream 0.15 m below the tap is (take g =10 ms

-2)

A) 5.0 10-4m2B) 1.0 10-5m2C) 5.0 10-5m2D) 2.0 10-5m2

68) A large open tank has two holes in the wall. One is a square hole of side L at a

depth y from the top and the other is a circular hole of radius R at a depth 4y from

the top. When the tank is completely filled with water, the quantities of waterflowing out per second from both the holes are the same. Then R is equal to

A)2

L

B) 2

L

C) L

D)2

L


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69) A cylindrical jar of cross-sectional area 0.01m2is filled with water to a height of

50 cm. It carries a tight-fitting piston of negligible mass. What is the pressure at

the bottom of the jar when mass of 1 kg is placed on the piston? Take g = 10ms-2A) 105paB) 6000 pa

C) 5000 paD) 1000 pa

70) Two vessels A and B of different shapes have the same base area and are filled

with water up to the same height h. The force exerted by water on the base is FAfor vessel A and FBfor vessel B. The respective weights of the vessels are WAand

WB. ThenA) FA> FB; WA> WB

B) FA= FB; WA>WBC) FA= FB; WAFB; WA=WB

71) A tank with a square base of area 2.0 m2is divided into two compartments by a

vertical partition in the middle. There is a small hinged door of face area 20cm2at

the bottom of the partition. Water is filled in one compartment and an acid, ofrelative density 1.5, in the other, both to a height of 4m. If g = 10 ms

-2, the force

necessary to keep the door closed isA) 10 N

B) 20 NC) 40 N

D) 80N


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72) A U-tube contains water and oil separated by mercury. The mercury columns inthe two arms are at the same level with 10 cm of water in one arm and 12.5 cm of

oil in the other, as shown in figure

The relative density of oil is

A) 0.8B) 1.0C) 1.25

D) 2.0

73) In Q. 72, 15 cm column more of water and oil each are poured into the respective

arms of the U-tube. If the relative density of mercury is K, the difference in thelevels of mercury in the two arms will be

A)K

1cm

B)K2 cm

C)K

3cm

D)K

4cm

74) A block of wood float in a liquid in a beaker with 3/4ths of its volume submergedunder the liquid. If the beaker is placed in an enclosure that is falling freely under

gravity, the block will

A)

float with ths of its volume submergedB) float completely submergedC) float with any fraction of its volume submerged

D) sink to the bottom.


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75) A cubical block of steel of each side equal tolis floating on mercury in a vessel.

The densities of steel and mercury are sand m. The height of the block abovethe mercury level is given by

A) l

m

s

1

B) l

m

s

1

C) l

s

m

1

D) l

s

m

1

76) A spring balance reads 10kg when a bucket of water is suspended from it. What

will be the reading of the balance when an iron piece of mass 7.2 kg suspended bya string is immersed with half its volume inside the water in the bucket? Relative

density of iron is 7.2.A) 10kg

B) 10.5kgC) 13.6 kg

D) 17.2 kg

77) A body floats in water with 40% of its volume outside water. When the same

body floats in oil, 60% of its volume remains outside oil. The relative density ofoil isA) 0.9

B) 1.2C) 1.5

D) 1.8

78) The relative density of ice is 0.9 and that of sea water is 1.125. What fraction of

the whole volume of an iceberg appears above the surface of the sea?A) 1/5

B) (b)2/5

C) 3/5D) 4/5


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79) A cube of wood supporting a mass of 200 g just floats in water. When the mass isremoved, the cube rises by 2 cm. What is the size of the cube?

A) 6 cm

B) 8cmC) 10 cmD) 12 cm

80) A boat carrying a number of large stones is floating in a water tank. What will

happen to the water level if the stones are unloaded into the water? The waterlevel

A) remains unchangedB) rises

C) fallsD) rises till half the number of stones are unloaded and then begins to fall

81) A piece of ice, with a stone frozen inside it, is floating in water contained in a

beaker. When the ice melts, the level of water in the beakerA) rises

B) fallsC) remains unchanged

D) falls at first and then rises to the same height as before

82) A piece of copper having an internal cavity, weighs 264 g in air and 221 g inwater. The density of copper is 8.8 g cm

-3. What is the volume of the cavity?

A) 12cm3

B) 13 cm3C) 14 cm

3

D) 15 cm3

83) A stone of relative density K is released from rest on the surface of a lake. If

viscous effects are ignored, the stone sinks in water with an acceleration ofA) g (1 K)

B) g(1 + K)

C) g

k

11

D) g

k11


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84) Two identical cylindrical vessels, each of base area A, have their bases at the

same horizontal level. They contain liquid of density. In one vessel the height

of the liquid is h1and in the other h2(> h1). When the two vessels are connected,

the work done by gravity in equalizing the levels is

A) 2Ag(h2 h1)2

B) Ag (h2 h1)2

C) Ag2

1(h2 h1)

2

D) Ag4

1(h2 h1)

2

85) A cylindrical jar has radius r .To what height h should it be filled with a liquid sothat the force exerted by the liquid on the sides of the jar equals the force exerted on

the bottom?

A) h =2

r

B) h = rC) h = 2rD) h = 4r

86) The work done to break up a drop of a liquid of radius R and surface tension intoeight droplets, all of the same size, is

A) 4 R2

B)

2 R2

C)

2

1R2

D)4

1R2

87) The excess pressure across a soap bubble of radius r is p =4/r, where is thesurface tension of soap solution. What is the excess pressure across an air bubble ofthe same radius r formed inside a container of soap solution?

A)r

B)r

2

C)r

4

D)r

8


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88) In Q.87, if the air bubble is formed at a depth h inside the container of soap

solution of density , the total pressure inside the bubble is (here P0denotes the

atmospheric pressure)

A)r

2+ hg

B)r

2- hg

C) P0+r

2+ hg

D) P0 +r

2- hg

89) Tiny insects can float and walk on the surface of water due toA) buoyancy alone

B) surface tension aloneC) both buoyancy and surface tension

D) neither buoyancy nor surface tension

90) A small drop of water of surface tension is squeezed between two clean glassplates so that a thin layer of thickness d and area A is formed between them. If theangle of contact is zero, the force required to pull the plates apart is

A)d

A

B)dA2

C)d

A4

D)d

A8

91) A small spherical ball of density is gently released in a liquid of density (). The initial acceleration of the free fall of the ball will be

A)

g

B)

g

C) g

D) g


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92) The time period of a simple pendulum is T. The pendulum is oscillated with its

bob immersed in a liquid of density . If the density of the bob is and viscouseffect is neglected, the time period of the pendulum will be

A)2

1

T

B)2

1

T

C)2

1

T

D)

2

1

T

93) A wooden block of mass m and density is tied to a string; the other end of thestring is fixed to the bottom of a tank. The tank is filled with a liquid of density with > What is the tension in the string?

A)

mg

B)

mg

C)

mg

D)

mg

94) Equal masses of two substances of densities 1and 2are mixed together. Thedensity of the mixture would be

A)2

1(1+ 2)

B) 21

C))21(

21

D))21(

212


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95) Equal volumes of two substances of densities 1and 2are mixed together. Thedensity of the mixture would be

A) 2

1(1+ 2)

B) (1+ 2)C) 21

D))21(

21

96) A capillary tube of radius r is immersed in water and water rises in it to a heighth. The mass of water in the capillary tube is 5 g . Another capillary tube of radius2r is immersed in water . The mass of water that will rise in this tube is

A) 2.5 gB) 5.0 g

C) 10 gD) 20 g

97) In a surface tension experiment with a capillary tube, water rises upto 0.1 m. If the

same experiment is repeated in an artificial satellite, which is revolving round theearth, water will rise in the capillary tube upto a height of

A) 0.1 mB) 0.2 m

C) 0.98 mD) full length of the capillary tube.

98) A concrete sphere of radius R has a cavity of radius r which is packed with

sawdust. The relative densities of concrete and sawdust are 2.4 and 0.3respectively. For this sphere to float with its entire volume submerged under

water, the ratio of the mass of concrete to the mass of sawdust will beA) 8

B) 4C) 3

D) Zero

99) A closed compartment containing gas is moving with some acceleration in ahorizontal direction. Neglecting the effect of gravity, the pressure in the

compartment will beA) same every where

B) lower in the front sideC) lower in the rear side

D) lower in the upper side


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100) A vessel contains oil(density 0.8 g cm-3

) over mercury ( density 13.6 g cm-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 g cm-3

is

A) 3.3B) 6.4C) 7.2

D) 12.8

101) A drop of water breaks into two droplets of equal size. Then which of thefollowing statements is correct?

A) the sum of temperatures of two droplets is equal to the originaltemperature

B) The sum of masses of two droplets is equal to the mass of the originaldrop

C) The sum of radii of two droplets is equal to the radius of the original dropD) The sum of surface areas of two drops is equal to surface area of the

original drop

102) A liquid does not wet the surface of a solid if the angle of contact isA) zero

B) 90o

D) of any value

103) The angle of contact of mercury - glass surface is

A) 8oB) 90

o

C) 0o

D) 135o

104) When two tubes of different diameters are dipped vertically, the rise of liquid isA) same in both tubes

B) more in tube of larger diameterC) more in tube of smaller diameter

D) none of these

105) The surface tension of a liquid with increase of temperature generallyA) increases

B) decreasesC) remains constant

D) decreases up to 100oC and then increases


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106) When the temperature increases, the angle of contact of a liquid willA) increase

B) decrease

C) remain unchangedD) first increase and then decrease

107) A water proofing agent will change the angle of contactA) from an obtuse to acute value

B) from an acute to obtuse value

C) from acute to 2/

D) from obtuse to 2/

108) One end of a towel dips into a bucket full of water and the other end hangs over

the bucket. It is found that after some time the whole towel becomes wet. This

happens becauseA) viscosity of water is highB) of capillary action of cotton threads

C) of gravitational forceD) of evaporation of water

109) The pressure just below the meniscus of water

A) is greater than just above itB) is less than just above it

C) is same as just above itD) is always equal to atmospheric pressure

110) The figure below represents three soap bubbles A, B and C prepared by blowing

the capillary tube with stop cocks S, S1, S2 and S3. With stop-cock S closed andS1, S2, S3opened

A) B will start collapsing with volumes of A and C increasingB) C will start collapsing with volumes of A and B increasing

C) Volumes of A, B, and C will becomes equal at equilibriumD) C and A will both start collapsing with volume of B increasing


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111) Two soap bubbles have radii in the ratio 2:1. What is the ratio of excess pressureinside them?

A) 1:2

B) 2:1C) 1:8D) 8:1

112) A soap bubble (surface tension= 30 10-3N-m-1) has radius 2 cm. The work donein doubling the radius isA) 0

B) 21.1355 10-4JC) 12.261 10-4JD) 4.043 10-4J

113) If the work done in blowing a bubble of radius R is W, then the work done inblowing a bubble of radius 2R from that solution is

A) W/2B) 2 W

C) 4WD) 21/3 W

114) A capillary tube of radius r can support a liquid of weight 6.28 10-4N. If thesurface tension of the liquid is 5 x 10-2N/m, the radius of the capillary must be

A) 2.5 10-4m

B)

1.5 10-3

mC) 2.0 10-4mD) 2.0 10-3m

115) The amount of work done in increasing the size of a soap film 10 cm 6 cm to10 cm 10 cm is (surface tension T = 0.030 N/m)A) 2.4 x 1o

-2J

B) 2.4 x 10-4

JC) 4.2 x 10-2J

D) 4.2 x 10-4

J

116) Which one of the following would a hydrogen balloon find easiest to lift?A) 1 kg of steel

B) 1 kg of waterC) 1 kg of lightly packed feathers

D) 1 kg of ice


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117) Bernoulli's theorem is based onA) conservation of momentum

B) conservation of energy

C) mass-energy equivalenceD) conservation of mass

118) If two ping-pong balls are suspended near each other and a fast stream of air isproduced within the space between the balls, the balls will

A) come closerB) move farther

C) remain in original positionD) fall down

119) A fast train goes past a wayside station platform at high speed. A person standing

at the edge of the platform tends to beA) pulled towards the train

B) pushed away from the trainC) affected only if the train's speed is more than the speed of sound

D) unaffected by the ongoing train

120) Paint-gun is an application ofA) Bernoulli's theorem

B) Archimedes principleC) Newtons law of motion

D) Boyles law

121) A hole is near the bottom of a tank. The volume of liquid emerging from the holedoes not depend upon

A) height of liquid level above holeB) area of hole

C) density of liquidD) gravitational acceleration

122) An application of Bernoullis equation for fluid flow is found in theA) dynamic lift of an aeroplane

B) viscosity meterC) hydraulic press

D) capillary rise


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123) A horizontal pipe line carries water in a stream line flow. At a point along thepipe where cross sectional area is 10 cm2, the water velocity is 1 m/s and the

pressure is 2000 Pa. The pressure of water at another point where the cross

sectional area is 5 cm2is (density of water =103kg-m-3)A) 1000 PaB) 500 Pa

C) 3500 PaD) 1625 Pa

124) A body is just floating in a liquid (their densities are equal). If the body is slightly

pressed and released it willA) start oscillating

B) sink to the bottomC) come back to the same position immediately

D) come back to the same position slowly

125) In order that a floating object remain in a stable equilibrium, its center ofbuoyancy should be

A) vertically above its center of gravityB) below its center of gravity

C) horizontally in line with its centre of gravityD) may be anywhere

126) The principle of working of a hydraulic press is based upon

A) Boyle's Law

B) Pascal's lawC) Daltons law of partial pressuresD) Newtons law of gravitation

127) A cylinder is filled with water of density upto a height h. If the beaker is at rest,the average pressure at the walls isA) 0

B) hgC) hg/2D) hg/6

128) A beaker has oil of relative density 1.2 upto a height of 3 cm. On top of the oil is awater column of height 10 cm. If the relative density of mercury is 13.6 , the

pressure at the bottom of the beaker isA) 1 cm of Hg

B) 10 cm of HgC) 15 cm of Hg

D) 25 cm of Hg


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129) A large piece of ice is floating in a jar containing water. When the ice melts, thelevel of water

A) rises

B) fallsC) remains unchangedD) rises or falls depending upon the size of piece

130) A boy is carrying a bucket of water in one hand and a piece of plastic in the other.

After transferring the plastic piece to the bucket (in which it floats) the boy willcarry

A) same load as beforeB) more load than before

C) either less or more load depending on the density of plasticD) less load than before

131) In a satellite orbiting around the earth, a coin is dropped in a beaker of water and

released. It willA) rise

B) sinkC) remain where left

D) oscillate

132) A body tied to a string is suspended in a beaker full of water. The system isallowed to fall freely. Then

A) Tension is equal to weight of body

B) Tension is zero and Archimedes law holds goodC) Tension is zero and Archimedes law is not validD) Tension in string is neither zero nor equal to mg but Archimedes law holds

133) A body floats in a liquid contained in a beaker. The whole system as shown below

in the figure falls freely under gravity. The upthrust on the body due to liquid is

A) Zero

B) equal to weight of liquid displacedC) equal to weight of the body in air

D) equal to weight of immersed portion of the body


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134) A man is sitting in a boat which is floating on a pond. If the man drinks somewater from the pond, the level of the water in the pond

A) decreases

B) increasesC) remains unchangedD) may decrease or increase depending on the weight of man

135) A cubical vessel of height 1 m is full of water. The work done in pumping water

out of the vessel isA) 49 J

B) 98 JC) 4900 J

D) 9800 J

136) A block of ice is floating in a liquid of specific gravity 1.2 contained in a beaker.When the ice melts completely, the level of liquid in the vessel

A) RisesB) Falls

C) remains unchangedD) first rises and then falls

137) A body floats with one-third of its volume outside water and three-fourth of its

volume outside another liquid. The density of the other liquid isA) 9/4 g/cm

3

B) 4.9 g/cm3

C) 8/3 g/cm3D) 3/8 g/cm

3

138) A body of volume 100 cm3is immersed completely in water contained in a jar.

The weight of the water and jar before immersion of the body was 700 gm. After

immersion the weight of the water and jar will beA) 700 g

B) 500gmC) 100 gm

D) 800 gm

139) A block of steel of size 5 cm 5 cm 5 cm is weighed in water. If the relativedensity of steel is 7 its apparent weight is

A) 6 5 5 5 gB) 4 4 4 7 gC) 4 4 4 6 gD) 5 5 5 7 g


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140) The spring balance A reads 2 kg with a block m suspended from it. A balance Breads 5 kg when a beaker with liquid is put on the pan of the balance. The two

balances are now so arranged that the hanging mass is inside the liquid in the

beaker as shown in the figure. In this situation

A) the balance A will read more than 2 kg

B) the balance B will read less than 5 kgC) the balance A will read less than 2 kg and B will read more than 5kg

D) the balance A will B will read 2 kg and 5 kg respectively

141) What is the apparent weight of wood floating in water if it weighs 100 g in air?

A) 200 gB) 400 g

C) 100 gD) zero

142) A drop of water breaks into two drops. In this process

A) energy is evolvedB) energy is absorbed

C) no energy is evolvedD) no energy is absorbed

143) The radius of a spherical soap bubble is 0.5 mm. If the surface tension of the soap

solution be 30 dyne/cm, the excess pressure isA) 1500 dyne/cm

2

B) 1000 dyne/cm2

C) 2400 dyne/cm2D) 1200 dyne/cm

2


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144) A vessel has a small hole at the bottom. Its radius is 0.4 mm. The height to whichwater can be put inside the vessel without any leakage (surface tension =72

dyne/cm, g =9.8 m/s2) will be

A) 3.67 cmB) 0.367 cmC) 0.0367 cm

D) zero

145) When a capillary tube is dipped in water, it rises in the tube upto 6 cm. If thisexperiment is repeated on the moon, water will rise upto

A) same heightB) 1 cm

C) 2 cmD) 36 cm

146) The reading of a pressure meter attached to a closed water pipe is 3.5 105N/m 2.On opening the valve, the reading of the pressure meter is reduced to 3 105N/m

2. Calculate the speed of water flowing in the pipe

A) 10m/s

B) 20 m/sC) 30 m/s

D) 40 m/s

147) An iceberg is floating partially immersed in sea water. The density of sea water is1.03 gm/cm

3and that of ice is 0.92 g/cm

3. The fraction of the total volume of the

ice berg above the level of sea water isA) 8 %

B) 11%C) 34 %

D) 89%

148) The work done to get n smaller equal size spherical drops from a bigger sizespherical drop of water is proportional to

A) 1/n2/3

-1B) 1/n

1/3-1

C) n1/3

-1

D) n4/3-1

149) Two soap bubbles, each with a radius r coalesce in a vacuum under isothermal

conditions to form a bigger bubble of radius R. Then R is equal toA) 2

-1/2r

B) 21/3rC) 2

1/2r

D) 2r


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150) A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks

by 1 cm when a man gets on it. The mass of the man is

A) 60 kgB) 72 kgC) 12 kg

D) 128 kg


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4. FLUID STATICS AND DYNAMICS

Ques. No. Answer

1 B

2 C

3 C

4 A

5 D

6 C

7 A

8 A

9 A

10 A

11 A

12 C

13 D

14 B

15 D

16 B

17 B

18 B

19 D

20 D

21 B

22 C

23 B

24 B

25 A

26 B

27 B

28 C

29 A

30 A

31 B

32 D

33 B

34 C

35 D

36 C

37 B

38 B

39 C

40 B

Ques. No. Answer

41 D

42 D

43 C

44 B

45 C

46 B

47 B

48 D

49 B

50 B

51 A

52 A

53 B

54 A

55 B

56 C

57 B

58 B

59 A

60 C

61 A

62 D

63 B

64 D

65 C

66 D

67 C

68 A

69 B

70 B

71 C

72 A

73 C

74 C

75 A

76 B

77 C

78 A

79 C

80 C


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Ques. No. Answer81 B

82 B

83 C

84 D

85 B

86 A

87 B

88 C

89 C

90 B

91 C

92 A

93 B

94 D

95 A

96 C

97 D

98 B

99 B

100 C

101 B

102 C

103 D104 C

105 B

106 B

107 B

108 B

109 B

110 D

111 A

112 D

113 C

114 D

115 B

Ques. No. Answer116 C

117 B

118 A

119 A

120 A

121 C

122 A

123 B

124 B

125 A

126 B

127 C

128 A

129 B

130 A

131 C

132 C

133 A

134 C

135 C

136 A

137 C

138 D139 A

140 C

141 D

142 B

143 C

144 A

145 D

146 A

147 B

148 C

149 C

150 A


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Fluid Statics and Dynamics (1)

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