Question- Pressure at a point inside a liquid does not depend on:
(a) the depth of the point below the surface of the liquid
(b) the nature of the liquid
(c) the acceleration due to gravity at that point
(d) the shape of the containing vessel
Ans- (d)
Question- Two stretched membranes of area 2 cm2 and 3 cm2 are placed in a liquid at the same depth. The ratio of the pressure on them is:
(a) 1 : 1
(b) 2 : 3
(c) 3 : 2
(d) 22 : 32
Ans-(a)
Question- A dam for water reservoir is built thicker at the bottom than at the top because:
(a) pressure of water is very large at the bottom due to its large depth
(b) water is likely to have more density at the bottom due to its large depth
(c) quantity of water at the bottom is large
(d) none of the above
Ans- (a)
Question- Two communicating vessels contain mercury. The diameter of one vessel is four times larger than the diameter of the other. A column of water of height h0 = 70 cm is poured into the left hand vessel (the narrower one). How much will be mercury level rise in the right hand vessel? (Specific density of mercury = 13.6)
(a) 0.3 cm
(b) 0.7 cm
(c) 0.1 cm
(d) 1.0 cm
Ans- (a)
Question- The pressure of water at bottom in a lake is 3/2 times that at half depth where the water barometer reads 10 m. The depth of the lake is:
(a) 15 m
(b) infinite
(c) 20 m
(d) 10 m
Ans- (a)
Question- A tank 5 m high is half filled with water and then is filled to the top with oil of denisty 0.85 g/cm3. The pressure at the bottom of the tank, due to these liquids, is:
(a) 1.85 gf/cm2
(b) 89.25 gf/cm2
(c) 462.5 gf/cm2
(d) 500 gf/cm2
Ans- (c)
Question- A piston of cross-sectional area 100 cm2 is used in a hydraulic press to exert a force of 107 dyne on the water.The cross-sectional area of the other piston which supports an object having a mass 2000 kg is:
(a) 100 cm2
(b) 109 cm2
(c) 2 × 104 cm2
(d) 2 × 1010 cm2
Ans-(c)
Question- 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:
(a) 6.25 cm
(b) 12.50 cm
(c) 31.25 cm
(d) 20 cm
Ans-(b)
Question- The height to which a cylindrical vessel be filed witha 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:
(a) half of the radius of the vessel
(b) radius of the vessel
(c) one-fourth of the radius of th vessel
(d) three-fourths of the radius of the vessel
Ans- (b)
Question- A cylindrical jar of cross-sectional area 0.01 m2 is 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 a mass of 1 kg is placed on the piston ? Take g = 10 ms–2.
(a) 105 Pa
(b) 6000 Pa
(c) 5000 Pa
(d) 1000 Pa
Ans-(b)
Question- When a body is wholly or partially immersed in a liquid it appears to lose weight. This loss of weight is equal to the weight to:
(a) water displaced by the body
(b) liquid displaced by the body
(c) equal volume of water
(d) equal volume of liquid
Ans- (b)
Question- Two pieces of metal when immersed in a liquid have equal upthrust on them; then:
(a) both pieces must have equal weights
(b) both pieces must have equal densities
(c) both pieces must have equal volumes
(d) both are floating to the same depth
Ans-(c)
Question- When a body is weighed in a liquid, the loss in its weight depends upon:
(a) volume of the body
(b) mass of the body
(c) shape of the body
(d) CG of the body
Ans- (a)
Question- An iron ball is weighed in air and then in water by a spring balance:
(a) its weight in air is more than in water
(b) its weight in water is more than in air
(c) its weight is same both in air and water
(d) its weight is zero in water
Ans- (a)
Question-A body weighs 40 g in air. If its volume is 10 cc, in water it will weigh:
(a) 30 g
(b) 40 g
(c) 50 g
(d) data are insufficient to calculate
Ans-(a)
Question- A block of metal (density 7 g/cc) of size 5 cm × 5 cm × 5 cm is weighed completely submerged in water. What will be its apparent weight (density of water = 1 g/cc)?
(a) (6 × 5 × 5 × 5)g
(b) (4 × 4 × 4 × 7)g
(c) (7 × 5 × 5 × 5)g
(d) (4 × 4 × 4 × 6)g
Ans-(a)
Question- A weightless rubber balloon has 100 g of water in it. Its weight in water will be:
(a) 100 g
(b) 200 g
(c) 50 g
(d) zero
Ans- (d)
Question- A beaker containing water weighs 100 g. It is placed on the pan of a balance and a piece of metal weighing 70 g and having a volume of 10 cm3 is placed inside the water in the beaker. The weight of the beaker and the metal would be:
(a) 170 g
(b) 160 g
(c) 100 g
(d) 30 g
Ans-(a)
Question- A body carries a fish in one hand and a bucket of water in the other hand; if he places the fish in the bucket, the weight now carried by him:
(a) is less than before
(b) is more than before
(c) is the same as before
(d) depends upon his speed
Ans- (c)
Question- The reading of a spring balance when a block is suspended from it in air is 60 N. This reading is changed to 40 N when the block is submerged in water. The specific gravity of the block must therefore be:
(a) 3
(b) 2
(c) 6
(d) 3/2
Ans-(a)
Question- A vessel contains oil of density 0.8 gcm–3 floating over mercury of density 13.6 gcm–3. A homogeneous sphere floats with half its volume immersed in mercury and the other half in oil. The density of the sphere in gcm–3 is
(a) 3.3
(b) 6.4
(c) 7.2
(d) 12.8
Ans- (c)
Question- When a ship floats on water:
(a) it displaces no water
(b) the mass of water displaced is equal to the mass of the ship
(c) the mass of water displaced is lesser than the mass of the ship
(d) the mass of water displaced is greater than the mass of the ship
Ans- (b)
Question- A block of wood is floating in a lake. The apparent weight of the floating block is
(a) equal to its true weight
(b) less than its true weight
(c) more than its true weight
(d) equal to zero
Ans- (d)
Question-Two bodies with volumes V and 2V are equalized on a balance. The larger body is then immersed in oil of density d1 = 0.9 g/cm3 while the smaller body is immersed in another liquid when it is found that the equilibrium of the balance is not disturbed. The density of the second liquid is then:
(a) 2.4 g/cm3
(b) 1.8 g/cm3
(c) 0.45 g/cm3
(d) 2.7 g/cm3
Ans- (b)
Question- A hydrogen-filled balloon stops rising after it has attained a certain height in the sky. This happens because
(a) the atmospheric pressure decreases with height and becomes zero when maximum height is attained
(b) the temperature of the air at maximum height equals that of the hydrogen in the balloon
(c) viscous effects become negligible
(d) at the highest point, the density of air is such that the buoyant force on the balloon equals its weight
Ans-(d)
Question- An iceberg is floating partially immersed in sea water. If the density of sea water is 1.03 g/cc and that of ice is 0.92 g/cc, the fraction of the total volume of iceberg above the level of sea water is:
(a) 8%
(b) 11%
(c) 34%
(d) 89%
Ans-(b)
Question-Two solids A and B float in a liquid. It is observed that A floats with half its volume immersed and B floats with (2/3) of its volume immersed. Compare the densities of A and B:
(a) 4 : 3
(b) 2 : 3
(c) 3 : 4
(d) 1 : 3
Ans-(c)
Question-A body weights W in air and it loses its weight by 25% in water. The relative density of the body is
(a) 4
(b) 1/4
(c) 3/4
(d) 4/3
Ans-(a)
Question- A body floats with (1/3) of its volume outside water and (3/4) of its volume outside another liquid. The density of the other liquid is:
(a) (9/4) g/cc
(b) (4/9) g/cc
(c) (8/3) g/cc
(d) (3/9) g/cc
Ans-(c)
Question- A raft of wood (density 600 g/m3) of mass 120 kg floats in water. How much weight can be put on the raft to make it just sink?
(a) 120 kg
(b) 200 kg
(c) 40 kg
(d) 80 kg
Ans-(d)
Question- A boat 3m long and 2 m wide is floating in a lake. When a man climbs over it, it sinks 1 cm further into water. The mass of the man is:
(a) 60 kg
(b) 64 kg
(c) 70 kg
(d) 72 kg
Ans-(a)
Question-A cubical block of wood of specific gravity 0.5 and a chunk of concrete of specific gravity 2.5 are fastened together.The ratio of mass of wood to the mass of concrete which makes the combination to float with its entire volume submerged in water is:
(a) 1/5
(b) 1/3
(c) 3/5
(d) 2/5
Ans-(c)
Question-A vessel contains an immiscible mixture of water and a liquid of density 0.8 gm/cc. A cube of side 10 cm is placed in the mixture and it is observed that the water-liquid interface is at the middle of cube height. Mass of the cube is:
(a) 420 gm
(b) 680 gm
(c) 225 gm
(d) 900 gm
Ans-(d)
Question-A metal ball of density 7800 kg/m3 is suspected to have a large number of inner cavities. It weighs 9.8 kg when weighed directly on a balance and 1.5 kg less when immersed in water. The fraction by volume of the cavities in the metal ball is apporximately:
(a) 20%
(b) 30%
(c) 16%
(d) 11%
Ans-(c)
Question- A man is sitting in a boat which is floating in a pond. If the man drinks some water from the pond, the level of water in the pond will:
(a) rise a little
(b) sink a little
(c) remain stationary
(d) none of these
Ans-(a)
Question- 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 water level
(a) remains unchanged
(b) rises
(c) falls
(d) rises till half the number of stones are unloaded and then begins to fall
Ans-(c)
Question- A wooden piece floats half submerged in a tub of water. If the system is transferred to a lift ascending with acceleration the wooden piece will:
(a) sink a little more
(b) rise a little
(c) remain half submerged
(d) sink to the bottom
Ans-(c)
Question-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 beaker
(a) rises
(b) falls
(c) remains unchanged
(d) falls at first and then rises to the same height as before.
Ans-(b)
Question- 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?
(a) It will come back slowly to its earlier position.
(b) It will remain submerged where it is left.
(c) It will sink.
(d) It will come out violently.
Ans-(c)
Question- A piece of ice floats in a vessel with water above which a layer of lighter oil is poured. When the whole of ice melts,which one of the following statements will be true?
(a) The level of the interface will remain the same.
(b) The total level of the liquids in the vessel will rise.
(c) The total level of the liquids in the vessel will fall while the level of interface will go up.
(d) The level of interface as well as the total level of liquids in the vessel will fall.
Ans-(c)
Question-Bernoulli’s theorem is a consequence of
(a) conservation of mass
(b) conservation of energy
(c) conservation of linear momentum
(d) conservation of angular momentum
Ans-(b)
Question- The velocity of efflux of a liquid through an orifice in the bottom of a tank does not depend upon
(a) density of liquid
(b) height of the liquid column above orifice
(c) acceleration due to gravity
(d) None of these
Ans-(a)
Question- A hole is made at the bottom of the tank filled with water (density = 1000 kg/m3). If the total pressure at the bottom of the tank is three atmospheres (1 atmosphere = 105 N/ m2), then the velocity of efflux is
(a) √400 m / s
(b) √200 m / s
(c) √600 m / s
(d)√ 500 m / s
Ans-(a)
Question- If the velocity head of a stream of water is equal to 10 cm then its speed of flow is approximately
(a) 1.0 m/s
(b) 1.4 m/s
(c) 140 m/s
(d) 10 m/s
Ans-(b)
Question- A water tank standing on the floor has two small holes punched in the vertical wall one above the other. The holes are 2.4 cm and 7.6 cm above the floor. If the jest of water from the holes hit the floor at the same point, then the height of water in the tank is :
(a) 10 cm
(b) 5 cm
(c) 20 cm
(d) 48 cm
Ans- (a)
Question- Water is flowing through two horizontal pipes of different diameters whcih are connected together. The diameter of the two pipes are 3 cm and 6 cm respectively. If the speed of water in the narrower tube is 4 m/s. Then, the speed of water in the wider tube is :
(a) 16 m/s
(b) 1 m/s
(c) 4 m/s
(d) 2 m/s
Ans- (b)
Question- The pressure of water in a pipe when tap is closed is 5.5 × 105 N/m2. When tap gets open, pressure reduces to 5 × 105 N/m2. The velocity with which water comes out on opening
the tap is :
(a) 10 m/s
(b) 5 m/s
(c) 20 m/s
(d) 15 m/s
Ans-(a)
Question- The ratio of the terminal velocities of two drops of radii R and R/2 is
(a) 2
(b) 1
(c) 1/2
(d) 4
Ans- (d)
Question- Units of coefficient of viscosity are
(a) Nms–1
(b) Nm2s–1
(c) Nm–2s
(d) None of these
Ans- (c)
Question- A rain drop of radius r falls in air with a terminal speed vt.What is the terminal speed of a rain drop of radius 2r ?
(a) vt/2
(b) vt
(c) 2vt
(d) 4vt
Ans- (d)
Question- Eight spherical rain drops of the same mass and radius are falling down with a terminal speed of 6 cm s–1. If they coalesce to form one big drop, what will be its terminal speed ? Neglect the buoyancy due to air.
(a) 1.5 cms–1
(b) 6 cms–1
(c) 24 cms–1
(d) 32 cms–1
Ans-(c)
Question- As the temperature of water increases, its viscosity
(a) remains unchanged
(b) decreases
(c) increases
(d) increases or decreases depending on the external pressure
Ans- (b)
Question- Two small drops of mercury each of radius r from a single large drop. The ratio of surface energy before and after this change is :
(a) 2 : 22/3
(b) 22/3 : 1
(c) 2 : 1
(d) 1 : 2
Ans- (a)
Question- If the angle of contact is less than 90°, then pressure just inside the surface of a meniscus
(a) is less than atmospheric pressure
(b) is greater than atmospheric pressure
(c) is same as the atmospheric pressure
(d) none of these
Ans- (a)
Question- Which of the following is not the unit of surface tension?
(a) Newton/metre
(b) Joule/(metre)2
(c) kg/(second)2
(d) 3Watt/metre
Ans- (d)
Question- Surface tension is due to
(a) friction forces between molecules
(b) cohesive forces between molecules
(c) adhesive forces between molecules
(d) gravitational forces
Ans- (b)
Question- The water droplets in free fall are spherical due to
(a) gravity
(b) viscosity
(c) surface tension
(d) intermolecular attraction
Ans- (c)
Question- Tiny insects can float and walk on the surface of water due to
(a) buoyancy alone
(b) surface tension alone
(c) both buoyancy and surface tension
(d) neither buoyancy nor surface tension
Ans-(c)
Question- The spiders and insects move and run on the surface of water without sinking, because
(a) elastic membrane is formed on water due to property of surface tension
(b) spiders and insects are lighter
(c) spiders and insects swim on water
(d) spiders and insects experience upthrust
Ans- (a)
Question- Small droplets of liquid are usually more spherical in shape than larger drops of the 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 gravity
(c) force of gravity predominates the force of surface tension
(d) force of gravity and force of surface tension act in the same direction and are equal
Ans- (b)
Question- Hair of shaving brush cling together when it is removed from water due to
(a) force of attraction between hair
(b) surface tension
(c) viscosity of water
(d) characteristic property of hair
Ans- (b)
Question- Water does not wet an oily glass, because
(a) cohesive force of oil > adhesive force between oil and glass
(b) cohesive force of oil > cohesive force of water
(c) oil repels water
(d) cohesive force of water > adhesive force between water and oil molecules
Ans- (d)
Question- Two water droplets coalesce to form a large drop. In this process,
(a) energy is liberated
(b) energy is absorbed
(c) energy is neither liberated nor absorbed
(d) a small amount of mass is converted into energy in accordance with Einstein’s mass-energy equivalence relation E = mc2.
Ans- (a)
Question- A mercury drop of radius 1 cm is sprayed into 106 drops of equal size. The energy expended in joule is (surface tension of mercury is 460 × 10–3 Nm–1)
(a) 0.057
(b) 5.7
(c) 5.7 × 10–4
(d) 5.7 × 10–6
Ans- (a)
Question- If two soaps bubbles of equal radii r coalesce, then the radius of curvature of interface between two bubble will be:
(a) r
(b) 0
(c) infinity
(d) r/2
Ans- (c)
Question- A glass plate is partly dipped vertically in the mercury and angle of contact is measured. If the plate is inclined, then the angle of contact will
(a) increase
(b) remain unchanged
(c) increase or decrease
(d) decrease
Ans- (b)
Question- A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is
(a) flat
(b) concave
(c) convex
(d) cylindrical
Ans-(b)
Question- If two soap bubble of different radii are in communication with each other
(a) air flow from larger bubble into the smaller one
(b) the size of the bubbles remains the same
(c) air flows from the smaller bubble into the large one and the larger bubble grows at the expense of the smaller one
(d) None of the above
Ans-(c)
Question- The excess pressure due to surface tension in a spherical liquid drop of radius r is directly proportional to
(a) r
(b) r2
(c) r–1
(d) r–2
Ans-(c)
Question- The liquid in the capillary tube will rise, if the angle of contact is
(a) 0°
(b) 90°
(c) obtuse
(d) acute
Ans-(a, d)
Question- If a capillary tube is dippped into liquid and the levels of the liquid inside and outside are same, then the angle of contact is :
(a) 0°
(b) 90°
(c) 45°
(d) 30°
Ans-(b)
Question- Water rises to a height of 30 mm in a capilary tube. If the radius of the capillary tube is made 3/4 of its previous value. The height to which the water will rise in the tube is:
(a) 30 mm
(b) 20 mm
(c) 40 mm
(d) 10 mm
Ans-(c)
Question- When two capillary tubes of different diameters are dipped vertically, then rise of the liquid is:
(a) same in both the tubes
(b) more in the tube of larger diameter
(c) less in the tube of smaller diameter
(d) more in the tube of smaller diameter
Ans-(d)
Question- Water rises up to 10 cm height in a long capillary tube. If this tube is immersed in water so that the height above the water surface is only 8 cm, then
(a) water flows out continuously from the upper end
(b) water rises upto upper end and forms a spherical surface
(c) water only rises upto 6 cm height
(d) water does not rise at all
Ans-(b)
Question- Spherical balls of radius R are falling in a viscous fluid of viscosity η with a velocity v. The retarding viscous force acting on the spherical ball is
(a) directly proportional to R but inversely proportional to v.
(b) directly proportional to both radius R and velocity v.
(c) inversely proportional to both radius R and velocity v.
(d) inversely proportional to R but directly proportional to velocity v.
Ans-(b)
Question- If two soap bubbles of different radii are connected by a tube
(a) air flows from the bigger bubble to the smaller bubble till the sizes become equal
(b) air flows from bigger bubble to the smaller bubble till the sizes are interchanged
(c) air flows from the smaller bubble to the bigger
(d) there is no flow of air.
Ans-(c)
Question- A cylinder of height 20 m is completely filled with water.The velocity of efflux of water (in ms–1) through a small hole on the side wall of the cylinder near its bottom, is
(a) 10
(b) 20
(c) 25.5
(d) 5
Ans-(b)
Question- 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
(a) 8 cm
(b) 10 cm
(c) 4 cm
(d) 20 cm
Ans-(d)
Question- If the terminal speed of a sphere of gold (density = 19.5 kgm–3) is 0.2 ms–1 in a viscous liquid (density = 1.5 kgm–3), find the terminal speed of a sphere of silver (density = 10.5 kg/m–3) of the same size in the same liquid.
(a) 0.4 ms–1
(b) 0.133 ms–1
(c) 0.1 ms–1
(d) 0.2 ms–1
Ans-(c)
Question- 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
(a) 25 /3πr2T
(b) 4πr2T
(c) 2πr2T
(d) 28/ 3πr2T
Ans-(d)
Question- Work done in increasing the size of a soap bubble from radius of 3 cm to 5 cm is nearly (surface tension of soap solution = 0.03 Nm–1)
(a) 0.2 π mJ
(b) 2 π mJ
(c) 0.4 π mJ
(d) 4 π mJ
Ans-(c)
Question- An open glass tube is immersed in mercury in such a way that a length of 8 cm extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additional 46 cm. What will be length of the air column above mercury in the tube now? (Atmospheric pressure - 76 cm of Hg)
(a) 22 cm
(b) 38 cm
(c) 6 cm
(d) 16 cm
Ans-(d)
Question- A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently,the temperature of the system is found to be 750C. T is given by :
(Given : Room temperature = 300C, Specific heat of copper = 0.1 cal/gm0C)
(a) 885°C
(b) 1250°C
(c) 825°C
(d) 800°C
Ans-(a)
Question- Water is flowing at a speed of 1.5 ms–1 through a horizontal tube of cross-sectional area 10–2m2 and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm, the minimum force that you must exert should be (density of water = 103 kgm–3).
(a) 15 N
(b) 22.5 N
(c) 33.7 N
(d) 45 N
Ans-(b)
Question- Two soap bubbles coalesce to form a single bubble. If V is the subsequent change in volume of contained air and S the change in total surface area, T is the surface tension and P atmospheric pressure, which of the following relation is correct?
(a) 2PV + 3ST = 0
(b) 3PV + 4ST = 0
(c) 4PV + 3ST = 0
(d) 3PV + 2ST = 0
Ans-(b)
Question- A tank with a small hole at the bottom has been filled with water and kerosene (specific gravity 0.8). The height of water is 3 m and that of kerosene 2 m. When the hole is opened the velocity of fluid coming out from it is nearly:
(take g = 10 ms–2 and density of water = 103 kg m–3)
(a) 8.5 ms–1
(b) 9.6 ms–1
(c) 7.6 ms–1
(d) 10.7 ms–1
Ans-(b)
Question- An air bubble of radius 0.1 cm is in a liquid having surface tension 0.06 N/m and density 103 kg/m3. The pressure inside the bubble is 1100 Nm–2 greater than the atmospheric pressure. At what depth is the bubble below the surface of the liquid? (g = 9.8 ms–2)
(a) 0.15 m
(b) 0.1 m
(c) 0.20 m
(d) 0.25 m
Ans-(b)
Question-The average mass of rain drops is 3.0×10–5 kg and their average terminal velocity is 9 m/s. Calculate the energy transferred by rain to each square metre of the surface at a place which receives 100 cm of rain in a year.
(a) 4.05 ×104 J
(b) 3.5 ×105 J
(c) 9.0 ×104 J
(d) 3.0 ×105 J
Ans-(a)
Question- The velocity of water in a river is 18 km/hr near the surface.If the river is 5m deep, find the shearing stress between the horizontal layers of water. The co-efficient of viscosity of water = 10–2 poise.
(a) 10–4 N/m2
(b) 10–1 N/m2
(c) 10–2 N/m2
(d) 10–3 N/m2
Ans- (c)
Question-A cylindrical block of wood (density = 650 kg m-3), of base area 30 cm2 and height 54 cm, floats in a liquid of density 900 kg m-3. The block is depressed slightly and then released. The time period of the resulting oscillations of the block would be equal to that of a simple pendulum of length (nearly) :
(a) 52 cm
(b) 65 cm
(c) 39 cm
(d) 26 cm
Ans-(a)
Question-A small spherical ball of radius r falls freely under gravity through a distance h before entering a tank of water. If,after entering the water, the velocity of the ball does not change, then h is proportional to
(a) r2
(b) r3
(c) r4
(d) r5
Ans- (c)
Question- When an air bubble of radius r rises from the bottom to the surface of a lake, its radius becomes 5r /4.Taking the atmospheric pressure to be equal to 10 m height of water column, the depth of the lake would approximately be (ignore the surface tension and the effect of temperature):
(a) 11.2 m
(b) 8.7 m
(c) 9.5 m
(d) 10.5 m
Ans- (c)
Question- A small soap bubble of radius 4 cm is trapped inside another bubble of radius 6 cm without any contact. Let P2 be the pressure inside the inner bubble and P0, the pressure outside the outer bubble. Radius of another bubble with pressure difference P2-P0 between its inside and outside would be:
(a) 12 cm
(b) 2.4 cm
(c) 6 cm
(d) 4.8 cm
Ans- (b)
Question-A beaker containing water is placed on the platform of a spring balance. The balance reads 1.5 kg. A stone of mass 0.5 kg and density 500 kg/m3 is immersed in water without touching the walls of the beaker. What will be the balance reading now?
(a) 2 kg
(b) 2.5 kg
(c) 1 kg
(d) 3 kg
Ans- (b)
Question- An ornament weighing 36 g in air weighs only 34 g in water. Assuming that some copper is mixed with gold to prepare the ornament, find the amount of copper in it. Specific gravity of gold is 19.3 and that of copper is 8.9.
(a) 2.2 g
(b) 4.4 g
(c) 1.1 g
(d) 3.6 g
Ans-(a)
Question- A large block of ice 5m thick has a vertical hole drilled through it and is floating in the middle of a lake. The minimum length of the rope required to scoop up bucket full of water through the hole is (the relative density of ice = 0.9)
(a) 1 m
(b) 0.9 m
(c) 0.5 m
(d) 0.45 m
Ans- (c)
Question- In a cylindrical water tank there are two small holes Q and P on the wall at a depth of h1 form upper level of water and at a height of h2 from the lower end of the tank respectively as shown in the figure. Water coming out from both the holes strike the ground at the same point. The ratio of h1 and h2 is
(a) 1
(b) 2
(c) > 1
(d) < 1
Ans- (a)
Question-Tanks A and B open at the top contain two different liquids upto certain height in them. A hole is made to the wall of each tank at a depth ‘h’ from the surface of the liquid. The area of the hole in A is twice that of in B. If the liquid mass flux through each hole is equal, then the ratio of the densities of the liquids respectively, is
(a) 2/1
(b) 3/2
(c) 2/3
(d) 1/2
Ans-(d)
Question- A capillary tube is immersed vertically in water and the height of the water column is x. When this arrangement is taken into a mine of depth d, the height of the water column is y. If R is the radius of the earth, the ratio x/y is
(a) (1 – d/R)
(b) (1 + d/R)
(c) (R – d/R + d)
(d) (R + d/R – d)
Ans- (a)
Question-A tiny sphere of mass m nad density x is dropped in a tall jar of glycerine of density y. When the sphere acquires terminal velocity, the magnitude of the viscious force acting on it is
(a) mgx/y
(b) mgy/x
(c) mg (1 – y/x)
(d) mg (1 + x/y)
Ans- (c)
Question-A tank with a square base of area 2.0 m2 is divided into two compartments by a vertical partition in the middle. There is a small hinged door of face area 20 cm2 at the bottom of the partition. Water is filled in one compartment and an acid of relative density 1.5 in the other, both to a height of 4 m. If g = 10 ms–2, the force necessary to keep the door closed is
(a) 10 N
(b) 20 N
(c) 40 N
(d) 80 N
Ans-(c)
Question-Length of exposed portion of top of box is equal to -
(a) 2m
(b) 3m
(c) 4m
(d) 2.5 m
Ans- (c)
Question-Water pressure at the bottom of centre of box is equal to (atmospheric pressure = 10-5 N/m2 , density of water = 1000 kg /m3 , g =10 m/ sec2 )
(a) 1.1 MPa
(b) 0.11 MPa
(c) 0.101 MPa
(d) 0.011 MPa
Ans- (b)
Question-Maximum value of water pressure in the box is equal to -
(a) 1.4 MPa
(b) 0.14 MPa
(c) 0.104 MPa
(d) 0.014 MPa
Ans- (b)
Question-What is the value of vertical acceleration of box for given horizontal acceleration (g/2), so that no part of bottom of box is exposed -
(a) g/2 upward
(b) g/2 downward
(c) g/4 upward
(d) not possible
Ans- (a)
Question- It is equidistant from the two stationary plates then the force exerted by the liquid on the plate is approximately :
(a) 0.53 N
(b) 0.26 N
(c) 0.72 N
(d) zero
Ans-(a)
Question-If the thin plate moves such that the plate is at a distance of 2 cm from one of the plates and 4 cm from the other, now the force exerted by the luqid on the plate is :
(a) 0.6 N
(b) 0.4/3 N
(c) 1.6/3 N
(d) None
Ans-(a)
Question- The net force on the glass window due to fluid pressure on both sides is
(a) πkN
(b) 2πkN
(c) π N
(d) 2π N
Ans-(b)
Question- The net force on the wall due to fluid pressure on both sides is
(a) 44000 kN
(b) 12100 kN
(c) 24200 kN
(d) 48400 kN
Ans-(c)
Question- If the glass window breaks, speed of water at this instant coming out through the window is
(a) 20 m/s
(b) 6 m/s
(c) 20.2 m/s
(d) 14 m/s
Ans-(a)
Question-The velocity of efflux is
(a) 10 ms–1
(b) 20 ms–1
(c) 4 ms–1
(d) 35 ms–1
Ans-(c)
Question- Horizontal force F to keep the cylinder in static equilibrium, if it is placed on a smooth horizontal plane, is
(a) 7.2 N
(b) 10 N
(c) 15.5 N
(d) 20.4 N
Ans-(a)
Question- Minimum and maximum values of F to keep the cylinder in static equilibrium just after the water starts to spill through the hole, if the coefficient of static friction between contact surfaces is 0.01, are
(a) 0, 40 N
(b) 5.4 N, 52.2 N
(c) 0, 70 N
(d) 0, 52.2 N
Ans-(d)
Question- Find the magnitude and direction of the force exerted by the hinge on the rod.
(a) 17/3 kgf in the downward direction
(b) 8 kgf in the downward direction
(c) 4 kgf in the downward direction
(d) 5 kgf in the downward direction
Ans-(a)
Question- Statement I : To float, a body must displace liquid whose weight is greater than the actual weight of the body.
Statement II : The body will experience no net downward force, in the case of floating.
(a) A
(b) B
(c) C
(d) D
Ans-(c)
Question-Statement I : All the raindrops hit the surface of the earth with the same constant velocity.
Statement II : An object falling through a viscous medium eventually attains a terminal velocity.
(a) A
(b) B
(c) C
(d) D
Ans-(d)
Question- Statement I : Tiny drops of liquid resist deforming forces better than bigger drops.
Statement II : Excess pressure inside a drop is directly proportional to surface tension.
(a) A
(b) B
(c) C
(d) D
Ans-(b)
Question-Statement I : Pascel’s law is the working principal of a hydraulic lift.
Statement II : Pressure is equal to thrust acting per unit area.
(a) A
(b) B
(c) C
(d) D
Ans-(b)
Question-A closed compartment containing gas is moving with some acceleration in horizontal direction. Neglect effect of gravity. Then, the pressure in the compartment is
(a) same everywhere
(b) lower in front side
(c) lower in rear side
(d) lower in upper side
Ans-(b)
Question-If the piston is pushed at a speed of 5mms–1, the air comes out of the nozzle with a speed of
(A) 0.1 ms–1
(B) 1 ms–1
(C) 2ms–1
(D) 8 ms–1
Ans-(c)
Question- In Bernoulli’s theorem which of the following is conserved?
(a) Mass
(b) Linear momentum
(c) Energy
(d) Angular momentum
Answer-(c)
Question-Pressure applied to enclosed fluid is
(a) increased and applied to every part of the fluid
(b) diminished and transmitted to wall of container
(c) increased in proportion to the mass of the fluid and then transmitted
(d) transmitted unchanged to every portion of the fluid and wall of containing vessel.
Answer-(d)
Question-The device which measures the flow speed of incompressible fluid is
(a) sphygmomanometer
(b) open-tube manometer
(c) venturimeter
(d) mercury barometer
Answer-(c)
Question-After terminal velocity is reached, the acceleration of a body falling through a fluid is
(a) equal to g
(b) zero
(c) less than g
(d) greater than g
Answer-(b)
Question- Bernoulli’s equation is important in the field of
(a) electrical circuits
(b) magnetism
(c) flow of fluids
(d) photoelectric effect
Answer-(c)
Question-Which of the following is a unit of pressure?
(a) atm
(b) pascal
(c) bar
(d) All of these
Answer-(d)
Question- Magnus effect is very near to the
(a) magnetic field
(b) electric field
(c) bernoulli’s theorem
(d) magnetic effect of current
Answer-(c)
Question-Liquid pressure depends upon
(a) area of the liquid surface
(b) shape of the liquid surface
(c) height of the liquid column
(d) directions
Answer-(c)
Question-Toricelli’s theorem is used to find
(a) the velocity of efflux through an orifice.
(b) the velocity of flow of liquid through a pipe.
(c) terminal velocity
(d) critical velocity
Answer-(a)
Question-According to archimedes' principle, loss of weight of a body immersed in a liquid is equal to
(a) weight of the liquid displaced
(b) weight of the total liquid
(c) weight of the body
(d) None of these
Answer-(a)
Question-When a body is wholly or partially immersed in a fluid at rest, the force working on it in upward direction is called
(a) buoyant force
(b) surface tension
(c) viscous force
(d) None of these
Answer-(a)
Question-The pressure at the bottom of a tank containing a liquid does not depend on
(a) acceleration due to gravity
(b) height of the liquid column
(c) area of the bottom surface
(d) nature of the liquid
Answer-(c)
Question-Beyond the critical speed, the flow of fluids becomes
(a) streamline
(b) turbulent
(c) steady
(d) very slow
Answer-(b)
Question-Streamline flow is more likely for liquids with
(a) high density and low viscosity
(b) low density and high viscosity
(c) high density and high viscosity
(d) low density and low viscosity
Answer-(b)
Question-The most characteristic property of a liquid is
(a) elasticity
(b) fluidity
(c) formlessness
(d) volume conservation
Answer-(d)
Question-For flow of a fluid to be turbulent
(a) fluid should have high density
(b) velocity should be large
(c) reynold number should be less than 2000
(d) both (a) and (b)
Answer-(d)
Question-Hydraulic lifts and hydraulic brakes are based on
(a) Archimedes' principle
(b) Bernoulli's principle
(c) Stoke's law
(d) Pascal's law
Answer-(d)
Question- In a stream line (laminar flow) the velocity of flow at any point in the liquid
(a) does not vary with time
(b) may vary in direction but not in magnitude
(c) may vary in magnitude but not in direction
(d) may vary both in magnitude and direction
Answer-(a)
Question- _________ and _________ play the same role in case of fluids as force and mass play in case of solids.
(a) Thrust and density
(b) Pressure and density
(c) Pressure and thrust
(d) thrust and volume
Answer-(b)
Question-Paint-gun is based on
(a) Bernoulli’s theorem
(b) Archimedes’ principle
(c) Boyle’s law
(d) Pascal’s law
Answer-(a)
Question-Specific gravity of a body is numerically equal to
(a) weight of the body in air
(b) weight of the body in water
(c) relative density of the body
(d) density of body in water
Answer-(c)
Question-A liquid is allowed to flow into a tube of truncated cone shape. Identify the correct statement from the following:
(a) the speed is high at the wider end and high at the narrow end.
(b) the speed is low at the wider end and high at the narrow end.
(c) the speed is same at both ends in a stream line flow.
(d) the liquid flows with uniform velocity in the tube.
Answer-(a)
Question-As the temperature of a liquid is raised, the coefficient of viscosity
(a) decreases
(b) increases
(c) remains the same
(d) may increase or decrease depending on the nature of liquid
Answer-(a)
Question-Which of the following pressure-measuring device measures the guage pressure?
(a) Mercury barometer
(b) Sphygmomanometer
(c) Both (a) & (b)
(d) None of these
Answer-(b)
