# Practice Test

Q1) If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake Show Answer

Q2) Equal masses of water and a liquid of density 2 are mixed together, and then the mixture has a density of Show Answer

Q3) The pressure at the bottom of a tank containing a liquid does not depend on Show Answer

Q4) 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 Show Answer

Q5) The volume of an air bubble becomes three times 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 Show Answer

Q6) The value of g at a place decreases by 2%. The barometric height of mercury Show Answer

Q7) A barometer kept in a stationary elevator reads 76 cm. If the elevator starts accelerating up the reading will be Show Answer

Q8) A beaker containing a liquid is kept inside a big closed jar. If the air inside the jar is continuously pumped out, the pressure in the liquid near the bottom of the liquid will Show Answer

Q9) The height to which a cylindrical vessel be filled with a homogeneous liquid, to make the average force with which the liquid presses the side of the vessel equal to the force exerted by the liquid on the bottom of the vessel, is equal to Show Answer

Q10) With rise in temperature, density of a given body changes according to one of the following relations Show Answer

Q11) Three liquids of densities d, 2 d and 3 d are mixed in equal volumes. Then the density of the mixture is Show Answer

Q12) Three liquids of densities d, 2 d and 3 d are mixed in equal proportions of weights. The relative density of the mixture is Show Answer

Q13) Why the dam of water reservoir is thick at the bottom? Show Answer

Q14) Air is blown through a hole on a closed pipe containing liquid. Then the pressures will Show Answer

Q15) Radius of an air bubble at the bottom of the lake is r and it becomes 2r when the air bubbles rises to the top surface of the lake. If P cm of water be the atmospheric pressure, then the depth of the lake is Show Answer

Q16) A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The specific gravities of concrete and sawdust are respectively 2.4 and 0.3 for this sphere to float with its entire volume submerged under water. Ratio of mass of concrete to mass of sawdust will be Show Answer

Q17) A silver ingot weighing 2.1 kg is held by a string so as to be completely immersed in a liquid of relative density 0.8. The relative density of silver is 10.5. The tension in the string in kg-wt is Show Answer

Q18) A sample of metal weighs 210 gm in air, 180 gm in water and 120 gm in liquid. Then relative density (RD) of Show Answer

Q19) Two solids A and B float in water. It is observed that floats with half its volume immersed and B floats with 2/3 of its volume immersed. Compare the densities of A and B Show Answer

Q20) Pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel. This law was first formulated by Show Answer

Q21) A body is just floating on the surface of a liquid. The density of the body is same as that of the liquid. The body is slightly pushed down. What will happen to the body Show Answer

Q22) A cork is submerged in water by a spring attached to the bottom of a bowl. When the bowl is kept in an elevator moving with acceleration downwards, the length of spring Show Answer

Q23) A hollow sphere of volume V is floating on water surface with half immersed in it. What should be the minimum volume of water poured inside the sphere so that the sphere now sinks into the water? Show Answer

Q24) A boat carrying steel balls is floating on the surface of water in a tank. If the balls are thrown into the tank one by one, how will it affect the level of water Show Answer

Q25) Two pieces of metal when immersed in a liquid have equal up thrust on them; then Show Answer

Q26) A wooden cylinder floats vertically in water with half of its length immersed. The density of wood is Show Answer

Q27) An ice block contains a glass ball when the ice melts within the water containing vessel, the level of water Show Answer

Q28) A large ship can float but a steel needle sinks because of Show Answer

Q29) Construction of submarines is based on Show Answer

Q30) In which one of the following cases will the liquid flow in a pipe be most streamlined Show Answer

Q31) Two water pipes of diameters 2 cm and 4 cm are connected with the main supply line. The velocity of flow of water in the pipe of 2 cm diameter is Show Answer

Q32) Air is streaming past a horizontal air plane wing such that its speed in 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 metre3 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 of Show Answer

Q33) A cylinder of height 20 m is completely filled with water. The velocity of efflux of water (in m/s) through a small hole on the side wall of the cylinder near its bottom is Show Answer

Q34) 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 Show Answer

Q35) 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 Show Answer

Q36) 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 Show Answer

Q37) Two drops of the same radius are falling through air with a steady velocity of 5 cm per sec. If the two drops coalesce, the terminal velocity would be Show Answer

Q38) The rate of steady volume flow of water through a capillary tube of length 'l' and radius 'r' under a pressure difference of P is V. This tube is connected with another tube of the same length but half the radius in series. Then the rate of steady volume flow through them is (The pressure difference across the combination is P) Show Answer

Q39) A liquid is flowing in a horizontal uniform capillary tube under a constant pressure difference P. The value of pressure for which the rate of flow of the liquid is doubled when the radius and length both are doubled is Show Answer

Q40) In a laminar flow the velocity of the liquid in contact with the walls of the tube is Show Answer

Q41) In a turbulent flow, the velocity of the liquid molecules in contact with the walls of the tube is Show Answer

Q42) The Reynolds number of a flow is the ratio of Show Answer

Q43) Water is flowing through a tube of non-uniform cross-section ratio of the radius at entry and exit end of the pipe is 3 : 2. Then the ratio of velocities at entry and exit of liquid is Show Answer

Q44) Water is flowing through a horizontal pipe of non-uniform cross-section. At the extreme narrow portion of the pipe, the water will have Show Answer

Q45) In a streamline flow Show Answer

Q46) An application of Bernoulli's equation for fluid flow is found in Show Answer

Q47) The Working of an atomizer depends upon Show Answer

Q48) The pans of a physical balance are in equilibrium. Air is blown under the right hand pan; then the right hand pan will Show Answer

Q49) At what speed the velocity head of a stream of water be equal to 40 cm of Hg Show Answer

Q50) The weight of an aeroplane flying in air is balanced by Show Answer

Q51) Fig. represents vertical sections of four wings moving horizontally in air. In which case the force is upwards Show Answer

Q52) A rectangular vessel when full of water takes 10 minutes to be emptied through an orifice in its bottom. How much time will it take to be emptied when half filled with water? Show Answer

Q53) A streamlined body falls through air from a height h on the surface of a liquid. If d and D (D > d) represents the densities of the material of the body and liquid respectively, then the time after which the body will be instantaneously at rest, is Show Answer

Q54) Velocity of water in a river is Show Answer

Q55) As the temperature of water increases, its viscosity Show Answer

Q56) The coefficient of viscosity for hot air is Show Answer

Q57) A good lubricant should have Show Answer

Q58) We have three beakers A, B and C containing glycerine, water and kerosene respectively. They are stirred vigorously and placed on a table. The liquid which comes to rest at the earliest is Show Answer

Q59) A small drop of water falls from rest through a large height h in air; the final velocity is Show Answer

Q60) In Poiseuilli's method of determination of coefficient of viscosity, the physical quantity that requires greater accuracy in measurement is Show Answer

Q61) Two capillaries of same length and radii in the ratio 1 : 2 are connected in series. A liquid flows through them in streamlined condition. If the pressure across the two extreme ends of the combination is 1 m of water, the pressure difference across first capillary is Show Answer

Q62) Water flows in a streamlined manner through a capillary tube of radius a, the pressure difference being P and the rate of flow Q. If the radius is reduced to a/2 and the pressure increased to 2P, the rate of flow becomes Show Answer

Q63) A viscous fluid is flowing through a cylindrical tube. The velocity distribution of the fluid is best represented by the diagram Show Answer

Q64) Water is flowing in a pipe of diameter 4 cm with a velocity 3 m/s. The water then enters into a tube of diameter 2 cm. The velocity of water in the other pipe is Show Answer

Q65) Water falls from a tap, down the streamline Show Answer

Q66) An incompressible fluid flows steadily through a cylindrical pipe which has radius 2r at point A and radius r at B further along the flow direction. If the velocity at point A is v, its velocity at point B is Show Answer

Q67) 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 water flowing out per second from both the holes are the same. Then R is equal to Show Answer

Q68) A block of ice floats on a liquid of density 1.2in a beaker then level of liquid when ice completely melts Show Answer

Q69) A lead shot of 1mm diameter falls through a long column of glycerine. The variation of its velocity v. with distance covered is represented by Show Answer

Q70) From amongst the following curves, which one shows the variation of the velocity v with time t for a small sized spherical body falling vertically in a long column of a viscous liquid Show Answer

Q71) Assertion : Pascal law is the working principle of a hydraulic lift.
Reason : Pressure is equal to thrust per area. Show Answer

Q72) Assertion : The blood pressure in humans is greater at the feet than at the brain.
Reason : Pressure of liquid at any point is proportional to height, density of liquid and acceleration due to gravity.

Q73) Assertion : Hydrostatic pressure is a vector quantity.
Reason : Pressure is force divided by area, and force is a vector quantity.

Q74) Assertion : To float, a body must displace liquid whose weight is greater than the actual weight of the body.
Reason :The body will experiences no net downward force, in the case of floating.

Q75) Assertion : A man sitting in a boat which is floating on a pond. If the man drinks some water from the pond, the level of the water in the pond decreases.
Reason : According to Archimede's principle the weight displaced by body is equal to the weight of the body. Show Answer

Q76) Assertion : A piece of ice floats in water, the level of water remains unchanged when the ice melts completely.
Reason : According to Archimede's principle, the loss in weight of the body in the liquid is equal to the weight of the liquid displaced by the immersed part of the body. Show Answer

Q77) Assertion : The velocity increases, when water flowing in broader pipe enter a narrow pipe.
Reason : According to equation of continuity, product of area and velocity is constant. Show Answer

Q78) In a stream line flow of a liquid, according to equation of continuity constant.
Where a is the area of cross section and v is the velocity of liquid flow. When water flowing in a broader pipe enters a narrow pipe, the area of cross-section of water decreases therefore the velocity of water increases. Show Answer

Q79) Assertion : The velocity of flow of a liquid is smaller when pressure is larger and vice-versa.
Reason : According to Bernoulli's theorem, for the stream line flow of an ideal liquid, the total energy per unit mass remains constant. Show Answer

Q80) Assertion : The shape of an automobile is so designed that its front resembles the stream line pattern of the fluid through which it moves.
Reason : The resistance offered by the fluid is maximum. Show Answer

Q81) Assertion : The size of the needle of a syninge controls flow rate better than the thumb pressure exerted by a doctor while administering an injection.
Reason : Flow rate is independent of pressure exerted by the thumb of the doctor. Show Answer

Q82) Assertion : A fluid flowing out of a small hole in a vessel apply a backward thrust on the vessel.
Reason : According to equation of continuity, the product of area and velocity remain constant. Show Answer

Q83) Assertion : For a floating body to be in stable equilibrium, its centre of buoyancy must be located above the centre of gravity.
Reason : The torque produced by the weight of the body and the up thrust will restore body back to its normal position, after the body is disturbed. Show Answer

Q84) Assertion : Water flows faster than honey.
Reason : The coefficient of viscosity of water is less than honey. Show Answer

Q85) Assertion : The viscosity of liquid increases rapidly with rise of temperature.
Reason : Viscosity of a liquid is the property of the liquid by virtue of which it opposes the relative motion amongst its different layers. Show Answer

Q86) Assertion : Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift.
Reason : According to Bernoulli's theorem, as velocity increases pressure decreases and vice-versa. Show Answer

Q87) Assertion : Sudden fall of pressure at a place indicates strom.
Reason : Air flows from higher pressure to lower pressure. Show Answer

Q88) Assertion : Machine parts are jammed in winter.
Reason :The viscosity of lubricant used in machine parts increase at low temperature. Show Answer

Q89) Assertion : A block of wood is floating in a tank containing water. The apparent weight of the floating block is equal to zero.
Reason : Because the entire weight of the block is supported by the buoyant force (the upward thrust) due to water. Show Answer

Q90) Assertion : A rain drop after falling through some height attains a constant velocity.
Reason : At constant velocity, the viscous drag is just equal to its weight. Show Answer

Q91) Assertion : Paper pins are made to have pointed end.
Reason : Because pointed pins have very small area due to which even for small applied force it exert large pressure on the surface. Show Answer

Q92) Assertion : Railways tracks are laid on small sized wooden sleepers.
Reason : Small sized wooden sleepers are used so that rails exert more pressure on the railway track. Due to which rail does not leave the track. Show Answer

Q93) Assertion : It is difficult to stop bleeding from a cut in the body at high altitudes.
Reason :The atmospheric pressure at high altitude is lesser than the blood pressure. Show Answer

Q94) Assertion : To empty an oil tank, two holes are made.
Reason : Oil will come out two holes so it will emptied faster. Show Answer

Q95) Assertion : Terminal velocity is same as the critical velocity.
Reason : The constant velocity of fall of a body through a viscous fluid is called terminal velocity. Show Answer

Q96) Assertion : When two boats sails parallel in the same direction and close to each other, they are pulled towards each other.
Reason : The viscous drag on a spherical body moving with speed v is proportional to v. Show Answer

Q97) Assertion : Cars and aeroplanes are streamlined.
Reason : This is done to reduce the backward drag due to atmosphere. Show Answer

Q98) Two different liquids are flowing in two tubes of equal radius. The ratio of coefficients of viscosity of liquids is 52:49 and the ratio of their densities is 13:1, then the ratio of their critical velocities will be Show Answer

Q99) A capillary tube is attached horizontally to a constant head arrangement. If the radius of the capillary tube is increased by 10% then the rate of flow of liquid will change nearly by Show Answer

Q100) Which of the following is not the characteristic of turbulent flow? Show Answer

Q101) To get the maximum flight, a ball must be thrown as Show Answer

Q102) The relative velocity of two consecutive layers is 8 cm/s. If the perpendicular distance between the layers is 0.1 cm, then the velocity gradient will be Show Answer

Q103) Under a constant pressure head, the rate of flow of liquid through a capillary tube is V. If the length of the capillary is doubled and the diameter of the bore is halved, the rate of flow would become Show Answer

Q104) A container with square base of side a hight H with a liquid. A hole is made at a depth h from the free surface of water. With what acceleration the container must be accelerated, so that the water does not come out? Show Answer

Q105) The pressure on a swimmer 20 m below the surface of water at sea level is Show Answer

Q106) Bernoulliâ€™s principle is not involved in the working/explanation of Show Answer

Q107) A soap bubble A radius 0.03 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 Show Answer

Q108) A piece of wax weighs 18.03 g in air. A piece of metal is found to weigh 17.03 g in water. It is tied to the wax and both together weigh 15.23 g in water. Then, the specific gravity of wax id Show Answer

Q109) If a drop of water is broken in to smaller drops the surface energy Show Answer

Q110) 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? Show Answer

Q111) A vertical glass capillary tube, open at both ends, contains some water. Which of the following shapes may be taken by the water in the tube? Show Answer

Q112) For a liquid which is rising in a capillary, the angle of contact is Show Answer

Q113) With the increase in temperature, the angle of contact Show Answer

Q114) An air-tight cage with a parrot sitting in it is suspended from the spring balance. The parrot starts flying. The reading of the spring balance will Show Answer

Q115) At critical temperature, the surface tension of a liquid is Show Answer

Q116) If two soap bubble of different radii are connected by a tube Show Answer

Q117) The meniscus of mercury in a capillary glass tube, is Show Answer

Q118) A glass tube 80 cm long and open at both ends is half immersed in mercury. Then the top of the tube is closed and it is taken out of the mercury. A column of mercury 20 cm long then remains in the tube. The atmospheric pressure (in cm of Hg) is Show Answer

Q119) A small spherical ball of steel falls through a viscous medium with terminal velocity v. If a ball of twice the radius of the first one but of the same mass is dropped through the same method, it will fall with a terminal velocity (neglect buoyancy) Show Answer

Q120) The height of the dam, in an hydroelectric power station is 10 m. In order to generate 1 MW of electric power, the mass of water (in kg) that must fall per second on the blades of the turbine is Show Answer

Q121) Angle of contact of a liquid with a solid depend on Show Answer

Q122) A liquid is allowed into a tube of truncated cone shape. Identify the correct statement from the following. Show Answer

Q123) A cube floats in water with 1/3 rd parts is outside the surface of water and it floats in liquid with 3/4 th part is outside the liquid then the density of liquid is Show Answer

Q124) A water tank, open to the atmosphere, has a leak in it, in the form of a circular hole, located at a height h below the open surface of water. The velocity of the water coming out of the hole is Show Answer

Q125) 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 Show Answer

Q126) When a pinch of salt or any other salt which is soluble in water is added to water, its surface tension Show Answer

Q127) The pressure inside two soap bubble is 1.01 and 1.02 atm respectively. The ratio of their respective volume is Show Answer

Q128) One drop of soap bubble of diameter D breaks into 27 drops having surface tension . The change in surface energy is Show Answer

Q129) 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 then ball jump out of water? Show Answer

Q130) Two rain drops of same radii 'r', falling with terminal velocity 'v' merge and form a bigger drops of radius R. The terminal velocity of the bigger drop is Show Answer

Q131) Water is flowing through a tube of non-uniform cross-section. Ratio of the radius at entry and exit end of the pipe is 3:2. Then the ratio of velocities at entry and exit of liquid is Show Answer

Q132) The excess pressure inside a spherical drop of water is four time that of another drop. Then their respective mass ratio is Show Answer

Q133) The rate of flow of liquid through a capillary tube of radius r is V when the pressure difference across the two ends of the capillary is p. If pressure is increased by 3 p and radius is reduced to r/2, then the rate of flow becomes Show Answer

Q134) Two solid pieces, one of steel and the other of aluminum when immersed completely in water have equal weights. When the solid pieces are weighed in air Show Answer

Q135) Two rain drops reach the earth with different terminal velocities having ratio 9:4. Then the ratio of their volume is Show Answer

Q136) By inserting a capillary tube upto a depth l in water, the water rises to a heighth. If the lower end of the capillary tube is closed inside water and the capillary is taken out and closed end opened, to what height the water will remain in the tube, when l > h ? Show Answer

Q137) A bigger drop of radius R is converted into n smaller drops of radius r, the required energy is Show Answer

Q138) Two pieces of metal when immersed in a liquid have equal upthrust on them; then Show Answer

Q139) If the work done in blowing a bubble of volume V is W, then the work done in blowing a soap bubble of volume 2V will be Show Answer

Q140) A weightless bag is filled with 5 kg of water and then weighed in water. The reading of spring balance is Show Answer

Q141) With an increase in temperature, surface tension of liquid (except molten copper and cadmium) Show Answer

Q142) If the length of tube is less and cannot accommodate the maximum rise of liquid then Show Answer

Q143) A marble of mass x and diameter 2 r is gently released a tall cylinder containing honey. If the marble displaces mass y ( < x ) of the liquid, then the terminal velocity is proportional to Show Answer

Q144) A sphere of mass M and radius R is dropped in a liquid, then terminal velocity of sphere is proportional to Show Answer

Q145) Streamline flow is more likely for liquid with Show Answer

Q146) The surface energy of a liquid drop is u. It is sprayed into 1000 equal droplets. Then its surface energy becomes Show Answer

Q147) Two capillary tubes of radii 0.2 cm and 0.4 cm are dipped in the same liquid. The ratio of heights through which liquid will rise in the tubes is Show Answer

Q148) If there were no gravity, which of the following will not be there for fluid? Show Answer

Q149) Two pieces of glass plate one upon the other with a little water in between them cannot be separated easily because of Show Answer

Q150) At which of the following temperatures, the value of surface tension of water is minimum? Show Answer

Q151) A rectangular plate 2m X 3m is immersed in water in such a way that its greatest and least depth are 6m and 4m respectively from the water surface. The total thrust on the plate is Show Answer

Q152) A cylinder is filled with liquid of density d upto a height h. If the cylinder is at rest, then the mean pressure of the walls is Show Answer

Q153) A capillary tube of radius R and length L is connected in series with another tube of radius R/2 and length L/4. If the pressure difference across the two tubes taken together is p, then the ratio of pressure difference across the first tube to that across the second tube is Show Answer

Q154) 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 Show Answer

Q155) The excess pressure inside one soap bubble is three times that inside a second soap bubble, then the ratio of their surface areas is Show Answer

Q156) A liquid does not wet the sides of a solid, if the angle of contact is Show Answer

Q157) Water rises in a capillary tube to a height h. Choose false statement regarding capillary rise from the following. Show Answer

Q158) A steel ball is dropped in oil then, Show Answer

Q159) A sphere liquid drop of radius R is divided into eight equal to droplets. If surface tension is T, then the work done in this process will be Show Answer

Q160) If a liquid is placed in a vertical cylindrical vessel and the vessel is rotated about its axis, the liquid will take the shape of figure Show Answer

Q161) 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 Show Answer

Q162) A cylindrical vessel is filled with equal amounts of weight of mercury on water. The overall height of the two layers is 29.2 cm, specific gravity of mercury is 13.6. Then the pressure of the liquid at the bottom of the vessel is Show Answer

Q163) The amount of work done in blowing a soap bubble such that its diameter increases from d to D is (S = surface tension of solution) Show Answer

Q164) A large open tank has two holes in its wall. One is a square hole of side a at a depth of x from the top and the other is a circular hole of radius r at a depth 4x from the top. When the tank is completely filled with water, the quantities of water flowing out per second from both holes are the same. Then r is equal to Show Answer

Q165) Choose the correct statement(s) for a cricket ball that is spinning clockwise through air
S1 : Streamlines of air are symmetric around the ball
S2 : The velocity of air above the ball relative to it is larger than that below the ball
S3 : The velocity of air above the ball relative to it is smaller than that below the ball
S4 : There is a net upward force on the ball

Q166) 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 Show Answer

Q167) A drop of oil is placed on the surface of water then it will spread as a thin layer because Show Answer

Q168) The excess pressure in a bubble of radius R of a gas in a liquid of surface tension S is Show Answer

Q169) A U-tube is partially filled with water. Oil which does not mix with water is next poured into one side until water rises by 25 cm. On the other side, if the density of oil be 0.8, the oil level will stand higher than the water level by Show Answer

Q170) A tank of height H is fully filled with water. If the water rushing from a hole made in the tank below the free surface, strikes the floor at maximum horizontal distance, then the depth of the hole from the free surface must be Show Answer

Q171) Two mercury drop (each of radius r) merge to form a bigger drop, if T is the surface tension is Show Answer

Q172) A ball of mass m and radius r is released in a viscous liquid. The value of its terminal velocity is proportional Show Answer

Q173) A drop of water breaks into two droplets of equal size. In this process, which of the following statements is correct ? Show Answer

Q174) The excess pressure inside a spherical drop of radius r of a liquid of surface tension T is Show Answer

Q175) A trough contains mercury to a depth of 3.6 cm. If some amount of mercury is poured in it then height of mercury in the trough will be Show Answer

Q176) Surface tension of a liquid is due to Show Answer

Q177) Surface tension vanishes at Show Answer

Q178) Water in a vessel of uniform cross-section escapes through a narrow tube at the base of the vessel. Which graph given below represents the variation of the height h of the liquid with timet? Show Answer

Q179) A block of ice floats on a liquid of density 1.2 in a beaker then level of liquid when ice completely melt Show Answer

Q180) A ring is cut from a platinum tube 8.5 cm internal diameter and 8.7 cm external diameter. It is supported horizontally from a pan of a balance so, that it comes in contact with the water is in glass vessel. If an extra 3.47 g - w t is required to pull it away from water, surface tension of water is Show Answer

Q181) 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 the force acting on a frame will be Show Answer

Q182) A capillary tube (A) is dipped in water. Another identical tube (B) is dipped in a soap-water solution. Which of the following shows the relative nature of the liquid columns in the two tubes ? Show Answer

Q183) 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 Show Answer

Q184) A body of uniform cross-sectional area floats in a liquid of density thrice its value. The portion of exposed height will be Show Answer

Q185) Under a pressure head, the rate of orderly volume flow of liquid through a capillary tube is Q. If the length of capillary tube were doubled and the diameter of the bore is halved, the rate of flow would become Show Answer

Q186) To what height should a cylindrical vessel be filled with a homogeneous liquid to make the force with which the liquid presses on the sides of the vessel equal to the force exerted by the liquid on the bottom of the vessel. If should be Show Answer

Q187) If two ping pong ball are suspended near each other and a fast stream of air is produced within the space of the balls, the balls Show Answer

Q188) The rate of flow of water in a capillary tube of length l and radius r is V. The rate of flow in another capillary tube of length 2l and radius 2r for same pressure difference would beThe rate of flow of water in a capillary tube of length l and radius r is V. The rate of flow in another capillary tube of length 2l and radius 2r for same pressure difference would be Show Answer

Q189) A block of wood weighs 4N in air and 3N when immersed in a liquid. The buoyant force in newton is Show Answer

Q190) The weight of an aeroplane flying in the air is balanced by Show Answer

Q191) Two tubes A and B are in series. Radius of A is R and that of B is 2R. If water flows through A with velocity then velocity of water through B is Show Answer

Q192) What change in surface energy will be noticed when a drop of radius R splits up into 1000 droplets of radiusr, surface tensionT? Show Answer

Q193) Two soap bubbles A and B are formed at the two open ends of a tube. The bubble A is smaller than bubbleB. Valve and air can flow freely between the bubbles, then Show Answer

Q194) A metallic sphere of mass M falls through glycerine with a terminal velocity v. If we drop a ball of mass 8 M of same metal into a column of glycerine, the terminal velocity of the ball will be Show Answer

Q195) For a ball falling in a liquid with constant velocity, ratio of the resistance force due to the liquid to that due to gravity is Show Answer

Q196) The excess of pressure inside the first soap bubble is three times that inside the second bubble in the ratio of their volume is Show Answer

Q197) A open U-tube contains mercury. When 11.2 cm of water is poured into one of the arms of the tube, how high dose the mercury rise in the other arm from its initial unit? Show Answer

Q198) When the temperature increases, the viscosity of Show Answer

Q199) What is the ratio of surface energy of 1 small drop and 1 large drop if 1000 drops combined to form 1 large drop? Show Answer

Q200) 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 100kg? Show Answer

Q201) A denotes the area to the right on the cube h the depth of an orifice of area of cross-sectionA, below the liquid surface. The velocity of the liquid flowing through the orifice is Show Answer

Q202) The reading of spring balance when a block is suspended from it in air is 60N. This reading is changed to 40N when the block is submerged in water. The specific gravity of the block must therefore Show Answer

Q203) A rectangular vessel when full of water, takes 10 min to be emptied through an orifice in its bottom. How much time will take to be emptied when half filled with water? Show Answer

Q204) Bernoulliâ€™s theorem is a consequence of the law of conservation of Show Answer

Q205) 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, the following relation is true. Show Answer

Q206) A body floats in a liquid contained in a beaker. If the whole system falls under gravity, them the upthrust on the body due to liquids is Show Answer

Q207) Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to smaller one? Show Answer

Q208) If two soap bubbles of different radii are connected by a tube Show Answer

Q209) A beaker containing water is balance on the pan of a common balance. A solid of specific gravity 1 and mass 5 g is tied to the arm of the balance and immersed in water contained in the beaker. The scale pan with the beaker Show Answer

Q210) An aquarium tank is in the shape of a cube with one side a 4m tall glass wall. When the tank is half filled and the water is 2 m deep, the water exerts a force F on the wall. What force does the water exerts on the wall when the tank is full and the water is 4 m drop? Show Answer

Q211) A small tiny lead shot is gently dropped on the surface of a viscous liquid Show Answer

Q212) At what speed, the velocity head of water is equal to pressure head of 40 cm of Hg? Show Answer

Q213) A parrot sitting on the floor of a wire cage which is being carried by a boy, starts flying. The boy will feel that the cage is now Show Answer

Q214) The potential energy of molecule on the surface of a liquid compared to one inside the liquid is Show Answer

Q215) A body weight 50 g in air and 40 g in water. How much would it weigh in a liquid of specific gravity 1.5? Show Answer

Q216) Water rises in a capillary tube to a heighth. It will rise to a height more than h Show Answer

Q217) When a number of small droplets combine to form a large drop, then Show Answer

Q218) Water rises in plant fibres due to Show Answer

Q219) Two spherical soap bubbles of radii a and b in vacuum coalesce under isothermal conditions. The resulting bubble has a radius given by Show Answer

Q220) When water flows at a rate Q through a tube of radius r placed horizontally, a pressure difference p develops across the ends of the tube. If the radius of the tube is doubled and the rate of flow halved, the pressure difference will be Show Answer

Q221) A solid of density D is floating in a liquid of densityd. If v is the volume of solid submerged in the liquid and V is the total volume of the solid, then v/V is equal to Show Answer

Q222) Two solid spheres of same metal but of mass M and 8M fall simultaneously on a viscous liquid and their terminal velocities are v and nv, then value of n is Show Answer

Q223) There is a hole of area A at the bottom of a cylindrical vessel. Water is filled upto a height h and water flows out in t sec. If water is filled to a height 4 h, then it will flow out in time Show Answer

Q224) 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 Show Answer

Q225) 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 stream-line flow is to be maintained and the pressure across first capillary is p, then the Show Answer

Q226) Surface tension of a soap solution is able of 2.0 cm diameter will be Show Answer

Q227) An ice block floats in a liquid whose density is less than water. A part of block is outside the liquid. When whole of ice has melted, the liquid level will Show Answer

Q228) The terminal velocity v of a spherical ball of lead of radius R falling through a viscous liquid varies with R such that Show Answer

Q229) Let W be the work done, when a bubble of volume V is formed from a given solution. How much work is required to be done to form a bubble of volume 2 V? Show Answer

Q230) Water rises to a height of 16.3 cm in a capillary of height 18 cm above the water level. If the tube is cut at a height of 12 cm in the capillary tube, Show Answer

Q231) A liquid does not wet the solid surface if the angle of contact is Show Answer

Q232) 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 Show Answer

Q233) Ice pieces are floating in beaker A containing water also in a beaker B containing miscible liquid of specific gravity 1.2. When ice melts, the level of Show Answer

Q234) Two liquid drops have diameters of 1 cm and 1.5 cm. The ratio of excess of pressure inside them is Show Answer

Q235) Aerofils are so designed that the speed of air Show Answer

Q236) On which of the following, the terminal velocity of a solid ball in a viscous fluid is independent? Show Answer

Q237) The surface area of air bubble increases four times when it rises from bottom to top of a water tank where the temperature is uniform. If the atmospheric pressure is 10 m of water, the depth of the water in the tank is Show Answer

Q238) In a streamline flow if the gravitational head is h. The kinetic and pressure heads are Show Answer

Q239) A large tank filled with water to a height h is to be emptied through a small hole at the bottom. The ratio of times taken for the level of water to fall from h to h / 2 and h / 2 to zero is Show Answer

Q240) In stream line flow of liquid, the total energy of liquid is constant at Show Answer

Q241) 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 Show Answer

Q242) A small spherical ball falling through a viscous medium of negligible density has terminal velocity v. Another ball of the same mass but of radius twice that of the earlier falling through the same viscous medium will have terminal velocity Show Answer

Q243) A piece of ice is floating in a jar containing water. When the ice melts, then the level of water Show Answer

Q244) Given below are two statements:
Statement I Pressure in a reservoir of water is same at all points at the same level of water. Statement II The pressure applied to enclosed water is transmitted in all directions equally.
In the light of the above statements, choose the correct answer from the options given below: Show Answer

Q245) Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R Assertion A When you squeeze One end of a tube to get toothpaste out from the other end, Pascal's principle is observed.
Reason R A change in the pressure applied to enclosed incompressible fluid is transmitted undiminished to every portion of the fluid and to the walls of its container.
In the light of the above statements, choose the most appropriate answer from the options given below. Show Answer

Q246) A wooden block floating in a bucket of water has 4/5 of its volume submerged. When certain amount of an oil is poured into the bucket, it is found that the block is just under the oil surface with half of its volume under water and half in oil. The density of oil relative to that of water is Show Answer

Q247) A liquid of density p is coming out of a hose pipe of radius a with horizontal speed v and hits a mesh. 50% of the liquid passes through the meshly unaffected, 25% losses all of its momentum and, 25% comes back with the same speed. The resultant pressure on the mesh will be Show Answer

Q248) A soap bubble, blown by a mechanical pump at the mouth of a tube, increases in volume, with time, at a constant rate. The graph that correctly depicts the time dependence of pressure inside the bubble is given by Show Answer

Q249) A long cylindrical vessel is half-filled with a liquid. When the vessel is rotated about its own vertical axis, the liquid rises up near the wall. If the radius of the vessel is 5 cm and its rotational speed is 2 rotations per second, then the difference in the heights between the centre and the sides (in cm) will be Show Answer

Q250) A hydraulic press can lift 100 kg when a mass m is placed on the smaller piston. It can lift ...... kg when the diameter of the larger piston is increased by 4 times and that of the smaller piston is decreased by 4 times keeping the same mass m on the smaller piston. Show Answer

Q251)
A small ball of mass M and density p is dropped in a viscous liquid of density po. After some time, the ball falls with a constant velocity. What is the viscous force on the ball? Show Answer

Q252) When a ball is dropped into a lake from a height 4.9 m above the water level, it hits the water with a velocity v and then sinks to the bottom with the constant velocity v. It reaches the bottom of the lake 4.0 s after it is dropped. The approximate depth of the lake is Show Answer

Q253) An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipes are 6.4 cm and 4.8 cm, respectively. The ratio of the minimum and the maximum velocities of fluid in this pipe is Show Answer

Q254) Which of the following options correctly describes the variation of the speed v and acceleration a of a point mass falling vertically in a viscous medium that applies a force F = -kv, where k is a constant, on the body? (Graphs are schematic and not drawn to scale) Show Answer

Q255) The water is filled upto height of 12 m in a tank having vertical sidewalls. A hole is made in one of the walls at a depth h below the water level. The value of h for which the emerging stream of water strikes the ground at the maximum range is ...... m. Show Answer

Q256) Eight equal drops of water are falling through air with a steady speed of 10 cm/s. If the drops coalesce, the new velocity is Show Answer

Q257) The height of liquid column raised in a capillary tube of certain radius when dipped in liquid A vertically is 5 cm. If the tube is dipped in a similar manner in another liquid B of surface tension and density double the values of liquid A, the height of liquid 00 column raised in liquid B would be .......... m. Show Answer

Q258) Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) Clothes containing oil or grease stains cannot be cleaned by water wash.
Reason (R) Because the angle of contact between the oil/grease and water is obtuse.
In the light of the above statements, choose the correct answer from the option given below. Show Answer

Q259) A water drop of diameter 2 cm is broken into 64 equal droplets. The surface tension of water is 0.075 N/m. In this process, the gain in surface energy will be: Show Answer

Q260) Two small drops of mercury each of radius R coalesce to form a single large drop. The ratio of total surface energy before and after the change is Show Answer

Q261) When two soap bubbles of radii a and b (b > a) coalesce, the radius of curvature of common surface Show Answer

Q262) A large number of water drops, each of radius 7, combine to have a drop of radius R. If the surface tension is T and mechanical equivalent of heat is J, the rise in heat energy per unit volume will be Show Answer

Q263) A small spherical droplet of density d is floating exactly half immersed in a liquid of density p and surface tension T. The radius of the droplet is (take note that the surface tension applies an upward force on the droplet) Show Answer

Q264) If M is the mass of water that rises in a capillary tube of radius r, then mass of water which will rise in a capillary tube of radius 2r is Show Answer

Q265) 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 p and L is its latent heat of vaporisation. Show Answer

Q266) 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 Show Answer

Q267) A spherical soap bubble of radius 3 cm is formed inside another spherical soap bubble of radius 6 cm. If the internal pressure of the smaller bubble of radius 3 cm in the above system is equal to the internal pressure of the another single soap bubble of radius r 1 cm. The value of r is .... Show Answer

Q268) A soap bubble of radius 3 cm is formed inside the another soap bubble of radius 6 cm. The radius of an equivalent soap bubble which has the same excess pressure as inside the smaller bubble with respect to the atmospheric pressure is ..... cm. Show Answer