Fluids Questions and Answers

A solid hemisphere of radius R is made to just sink in a liquid of density p Consider hydrostatic force only i e do not take atmospheric pressure into consideration Mark the CORRECT statements V Vertical hydrostatic force on the curved surface is given by Mpg R 3 Vertical hydrostatic force on the curved surface is given by 2xpgR Horizontal hydrostatic force on right half of curved surface SP9R Horizontal hydrostatic force on right half of curved surface 3x 4 pgR

CAPILLARY TUBE RISE Water rises to a heighth in capillary tube If the length of capillary tube above the surface of water is made less than h then a water rises upto a point a little below the top and stays there b water does not rise at all c water rises upto the tip of capillary tube then starts overflowing like a fountain d water rises upto the top of capillary tu stays there without overflowing

A certain number of spherical drops of a liquid of radius T coalesce to form a single drop of radius R and volume V If T is the surface tension of the liquid then R 4VT 1 7 3 energy 3VT VT 1 12 is released R 4 Energy is neither released nor absorbed 1 energy 2 energy 3VT is released is absorbed

filled with same volume of two liquids of densities and 2p is moving with an acceleration a on the horizontal plane If the height difference between the two surfaces open to atmosphere becomes zero then the height h is given by a

Horizontal tube of non uniform cross section has radii of 0 1m and 0 05m respectively at M and N For a streamiline flow of liquid the rate of liquid flow is M Continuously changes with time Greater at M than at N N Greater at N than at M CORRECT ANSWER

When incompr rises up in a vertical tube of uniform cross sectional area Its kinetic energy per unit length at an instant 1 Decreases with height 2 Increases with height 3 Constant with height coxon

Two vessels A and B have the same base area and contain water to same height but the mass of water in A is four times that in B The ratio of the liquid thrust at the base of A to that at the base of B is A l 10 B l H

Soap solution is used for cleaning dirty clothes because surface tension of solution is decreased viscosity of solution is increased temperature of solution is decreased surface tension of solution in increased

A small metal sphere of mass M and density d when dropped in a jar filled with liquid moves with terminal velocity after some time The viscous force acting on the sphere is d density of liquid g gravitational acceleration Mg 1 2 Mg 1 d Mg 1

If pressure at half of the depth of lake is equal to 3 pressure at the bottom of the lake then what 4 is the depth of the lake Patm 105 N m 20 m 10 m 40 m 5 m

A metal sphere of mass m and density 0 falls with terminal velocity through a container containing liquid The density of liquid is 0 The viscous force acting on the sphere is 02 mg 1 mg 1 1 02 51 mg 1 01 02

4 12 cm of water less than atmospheric pressure w w to 29 A solid of mass 1 6 kg and density 2 4 x 10 kgm is completely immersed in water The loss of we 1 0 66 N 2 0 66 kg wt 3 6 6 kg wt 4 66 N W

9 The height of mercury in a barometer at sea level is higher than that at the top of a hill Which of the following inferences about this observation is correct A The air molecules at sea level have higher mass than that at the top of a hill B The air molecules at sea level experience less gravitational force than that at the top of a hill C The air molecules per unit volume at sea level is greater than that at the top of a hill D The speed of air molecules at sea level is lower than that at the top of a hill E None of these

I think in calculating fractional char ge in density only gamma T is used why it is dividing Answer 3 When the temperature of a liquid is increased by AT C the mass will remain unchanged while due to thermal expansion volume will increase and become V V V 1 YAT where is the coefficient of volume expansion of liquid m m P V V 1 YAT 1 7AT Fractional change in density YAT 1 YAT 1 1 YAT 49 105 x 30 1 49 10 30 1470x10 1 1470x10 5 0 0147 1 0147 p p P 0 0145 1 5x10

Streamline flow is more likely for liquids with i High density ii High viscosity iii Low density iv Low viscosity Correct option is Question Type Single Correct Type 1 2 3 i iv iii iv i iii US O GUY

2 28 A long thin string has a coat of water on it The radius of the water cylinder is r After some time it was found that the string had a series of equally spaced identical water drops on it Find the minimum distance between two successive drops

A cylindrical tank is filled with water to level of 3 m A hole is opened at height of 52 5 cm from bottom The ratio of the area of the hole to that of cross sectional area of the cylinder is 0 1 The square of the speed with which water is coming out from the orifice is Take g 10 m s 1 50 m s 3 3 51 5 m s NEET 2016 2 40 m s 2 4 50 5 m s

8 A glass tube of radius R is covered with a liquid film at its one end Air is blown slowly into the tube to gradually increase the pressure inside What is the maximum pressure that the air inside the tube can have Assume that the liquid film does not leave the surface whatever its size and it does not get punctured Surface tension of the liquid is T and atmospheric pressure is Po D Liquid film

An open square tank of side 1m is com pletely filled with water If the tank is m oved with an acceleration at 10ms fi nd the slope of the free surface of wate r with the horizontal with deep explanat ion

on a horizontal surface A small spherical object of density p 0 is fastened to the bottom of the vessel with the help of the vessel with the help of a string as shown in the figure Neglect the viscosity and assume the gravity g vertically downwards if the vessel is now given a constant horizontal acceleration equal to g towards right then at the position of equilibrium of the spherical object with respect to the vessel the deflection of the string with the vertical is assume object always remains submerged Options a towards left with angle tan A b towards right with angle 4 c towards left with angle 4 d towards right with angle p

A spherical ball contracts in volume by 0 08 when subjected to a normal uniform pressure of 500 atm What is the bulk modulus of ball a 4 7 x 105 N m 2 107 N m b 5 x 107 N m d 6 3 1010 N m 05mm by a

Three holes A B and C are made in an empty can at different levels one over the other as shown in the figure They are temporarily closed with an adhesive tape The can is now filled with water What will you observe when the tape on all of them is pulled out Justify your answer

29 The time period of a bob performing simple harmonic 4 10 kg m motion in water is 2s If density of bob is 3 then time period of bob performing simple harmonic motion in air will be a 3s b 4s d As c 2s

A piece of steel has a weight w in air w whe completely immersed in water and w whe completely immersed in an unknown liquid The relative density specific gravity of liquid is 3 W W W W W W W 2 W W W W W W W W

A liquid of density p is completely filled in a cubical container as shown in figure Neglect the atmospheric pressure match the quantities in List I with corresponding expression in List II and select the CORRECT code List I N P Force on rectangular Face 1 is Q Force on rectangular Face 2 is R Force on triangular Face 3 is S Force on triangular Face 4 is A P 3 Q 1 R 2 S 4 1 2 a 3 9 1 2 a 3 List II 1 3 a pg 3 00 16 apg 3 a pg 3 3 4 8 B P 1 Q3 R 2 S 4 a pg

An object hangs from a spring balance The balance registers 30 N in air 20 N when this object is immersed in water and 24 N when the object is immersed in another liquid of unknown density What is the density of that other liquid

A 1 00 kg beaker containing 2 00 kg of oil density 916 0 kg m rests on a scale A 2 00 kg block of iron is suspended from a spring scale and completely submerged in the oil as shown in figure Determine the equilibrium reading of both scales

32 A body B is capable of remaining stationary inside a liquid at the position shown in Fig a If the whole system is gently placed on smooth inclined plane Fig b and is allowed to slide down then 0 0 90 B B 0 b a 1 The body will move up relative to liquid 2 The body will move down relative to liquid 3 The body will remain stationary relative to liquid 4 The body will move up for some inclination 0 and will move down for anoth

if excess pressure inside a spherical soap bubble of radius 1 cm is balanced by that due to a column of oil of specific gravity 0 9 1 36 mm high what is the surface tension O 2999 8 dyne cm O 2 9988 dyne cm O 29 988 dyne cm O 299 98 dyne cm

The figure shows a conical container of half apex angle 37 filled with certain quantities of kerosene and water The force exerted by the water on the kerosene is approximately Take atmospheric pressure 105 Pa Po 105 Pa 10 m 8 m Kerosene sp gr 0 8 Water sp gr 1 0

A bubble of radius R is at the bottom of a vessel filled with water making a circular contact of radius r with the bottom of the vessel If r R and the surface tension of water is T then value of r just before bubble detaches is density of water is Pw O R 2pwg 3 T Pwg OR 6T

A container is accelerating with acceleration a g along the direction as shown below The angle 0 in degree made by the liquid surface with the vertical wall of the container is 130 a g

A candle of radius 1 cm is floating in a liquid in a cylindrical container of radius 1 m If the candle is burning at the rate of 1 5 cm h then the top of the candle will in the given figure 1 Fall at the rate of 1 5 cm h 2 Remain at the same height 3 Fall at the rate of 3 cm h 4 Fall at the rate of 0 75 cm h

Mercury is poured into a U tube in which the cross sectional area of the left hand limb is three times smaller than that of the right one The level of the mercury in the narrow limb is a distance l 30cm from the upper end of the tube How much will the mercury level rise in the right hand limb if the left one is filled to the top with water

Two vertical conducting cylinders A and B of different cross sections are connected by a thin tube as shown An ideal gas is trapped in the cylinders by two airtight pistons of masses 1 0 kg and 2 0 kg respectively Initially the pistons as at the same height 40 cm above the base of the cylinders If an additional mass of 10 g were gently placed on the piston in the cylinder A which of the following statements correctly describe the new steady state ultimately reached A B LL 40cm Which of the following statements is correct A Pressure of the gas has been increased B Pressure of the gas remains unchanged C Pressure of the gas has decreased

50 A solid cylinder of length is in equilibrium in two different liquids A and B as shown in the figure If P density of the cylinder is P then value of P Q P and Q are co prime numbers Density of liquid A p and density of liquid B 3p is 2013 A B

estion 11 A rectangular vessel of dimension lxbxh and mass M contains a liquid of density p The vessel has an orifice at its bottom at a distance c from the rear wall as shown in the figure 0 1 The maximum volume of the water that can be stored when the vessel is accelerated is hcb 2 The maximum volume of the water that can be stored when the vessel is accelerated is hlb 2 Force E that must be applied when maximum water stored is M hcbp 2 hg c

A liquid flows out of a broad vessel through a narrow vertical pipe The height of the liquid level in vessel is H from the lower end of the pipe and the length of pipe is h as shown in figure assume atmospheric pressure Po Answer the following questions A X 2g H x h The velocity of the liquid at point B is 2g H h x Read Less

A container filled with air under pressure Po contains a soap bubble of radius R The air pressure has been reduced to half isothermally and the new radius of the bubble becomes If the surface tension of the soap water solution is S P is 5R 4 found to be 16nS SI unit Find n

A solid cone of uniform density and height 2K and base R has a conical portion scooped out from its base with the same base radius but height R as shown in the figure The solid one is floating in a liquid of density p with vertex A touching the fluid surface if atmospheric pressure is po the force acting on the surface BCD due to liquid is A A B C TR pg 2 2 3 TR pg B 9 5 3 3 TR pg 9 1 2 3 Rpg TR pg 4 3po HIZLI 2R

A light ray falls on a square glass slab as shown in the diagram The index of refraction of the glass if total internal reflection is to occur at the vertical face is equal to 45 Incident ray

7 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 1 d D 3 h 2 1 1 h 1h 4 Zero HA A air 80 g in water

heats a metal rod The wire provides a constant power P to the rod The metal rod is enclosed in an insulated container It is observed that the temperature T in the metal rod changes with time t as T t To 1 Bt 4 where is a constant with appropriate dimension temperature The heat capacity of the metal is A C 4P T t T BATO 4P T t T B T2 B D while To is a constant with dimension 4P T t To B T2 4P T t To R4T4 20

The two feet of a 60kg person cover an area of 500 cm Find the pressure exert by the two feet on the ground Select one O a 1 17kPa O b 15 76kPa O c 11 76kPa O d 1 2kPa

The workdone in blowing a soap bubble from an initial surface area of 0 5 cm to a final surface area of 1 1 cm will be surface tension soap solution is 3 10 Nm O 18 10 7 J 36 x 10 73 90 10 7 J 072 10 7 J

A jet of water with cross section of 6 cm 60 to the normal and rebounds elastically from the wall wi energy If the velocity of the water in the j t is 12 m s the the wall is 0 864 N 86 4 N O 72 N O 7 2 N

5 45 Determine the magnitude and direction of the anchoring force needed to hold the horizontal elbow and nozzle combination shown in Fig P5 47 in place Atmospheric pressure is 100 kPa The gage pressure at section 1 is 100 kPa At section 2 the water ex its to the atmosphere V V 160 mm Section 2 300 mm Water Section 1 P 100 kPa V 2 m s

Air is streaming past a horizontal airplane wing such that its speed is 120 m s over the upper surface and 90 m s at the lower surface If the density of air is 1 3 kg per metre and the wing is 10 m long and has an average width of 2 m then the difference of the pressure on the two sides of the wing is O 4095 0 pascal O 409 50 pascal O 40 950 pascal 4 0950 pascal

A soap bubble of radius 3 cm is charged with 9 0 nC The excess pressure inside the bubble if surface tension of soap solution 3 10 N m is 1 0 26 N m 3 0 44 N m 2 0 36 N m 4 0 52 N m

Section 2 Numerical value type In a hurricane the air density 1 2 kg m is blowing over a roof of surface area 80 m with a speed v If t maximum force that can be withstood by the roof mountings is 80 KN then find the maximum value of m s for which the roof would not be lifted up