# MCQ Questions Chapter 10 Mechanical Properties of Fluids Class 11 Physics

Please refer to MCQ Questions Chapter 10 Mechanical Properties of Fluids Class 11 Physics with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 11 Physics issued for the current academic year. We have provided MCQ Questions for Class 11 Physics for all chapters on our website. Students should learn the objective based questions for Chapter 10 Mechanical Properties of Fluids in Class 11 Physics provided below to get more marks in exams.

## Chapter 10 Mechanical Properties of Fluids MCQ Questions

Please refer to the following Chapter 10 Mechanical Properties of Fluids MCQ Questions Class 11 Physics with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 10 Mechanical Properties of Fluids Class 11 Physics

Question. The constant velocity attained by a body while falling through a viscous medium is termed as
(a) critical velocity
(b) terminal velocity
(c) threshold velocity
(d) None of these

B

Question. An ice-berg floating partly immersed in sea water of density 1.03 g/cm3. The density of ice is 0.92 g/cm3. The fraction of the total volume of the iceberg above the level of sea water is
(a) 8.1%
(b) 11%
(c) 34%
(d) 0.8%

B

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

A

Question. Fevicol is added to paint to be painted on the walls, because
(a) it increases adhesive force between paint and wall.
(b) it decreases adhesive force between paint and wall molecules.
(c) it decreases cohesive force between paint molecules.
(d) None of these

A

Question. A boat having a length of 3 metres and breadth 2 metres is floating on a lake. The boat sinks by one cm when a man gets on it. The mass of the man is
(a) 60 kg
(b) 62 kg
(c) 72 kg
(d) 128 kg

A

Question. A beaker containing a liquid of density P moves up with an acceleration a. The pressure due to the liquid at a depth h below the free surface of the liquid is

C

Question. The excess of pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is
(a) 0.125
(b) 0.250
(c) 1
(d) 2

A

Question. The rain drops falling from the sky neither injure us nor make holes on the ground because they move with
(a) constant acceleration
(b) variable acceleration
(c) variable speed
(d) constant terminal velocity

B

Question. The density of ice is x gram/litre and that of water is y gram/ litre. What is the change in volume when m gram of ice melts?

C

Question. A cylinder is filled with non-viscous liquid of density d to a height h0 and a hole is made at a height h1 from the bottom of the cylinder. The velocity of the liquid issuing out of the hole is

B

Question. A vessel with water is placed on a weighing pan and it reads 600 g. Now a ball of mass 40 g and density 0.80 g cm–3 is sunk into the water with a pin of negligible volume, as shown in figure keeping it sunk. The weighting pan will show a reading

(a) 600 g
(b) 550 g
(c) 650 g
(d) 632 g

C

Question. A rain drop of radius 0.3 mm has a terminal velocity in air = 1 m/s. The viscosity of air is 8 × 10–5 poise. The viscous force on it is
(a) 45.2 × 10–4 dyne
(b) 101.73×10–5 dyne
(c) 16.95 × 10–4 dyne
(d) 16.95 × 10–5 dyne

A

Question. 1 m3 water is brought inside the lake upto 200 metres depth from the surface of the lake. What will be change in the volume when the bulk modulus of elastically of water is 22000 atmosphere? (density of water is 1 × 103 kg/m3 atmosphere pressure = 105 N/m2 and g = 10 m/s2)
(a) 8.9 × 10–3 m3
(b) 7.8 × 10–3 m3
(c) 9.1 × 10–4 m3
(d) 8.7 × 10–4 m3

C

Question. 1 centipoise is equal to
(a) 1 kg m–1 s–1
(b) 1000 kg m–1 s–1
(c) 0.1 kg m–1 s–1
(d) 0.001 kg m–1 s–1

D

Question. Horizontal tube of non-uniform cross-section has radii of 0.1 m and 0.05 m respectively at M and N for a streamline flow of liquid the rate of liquid flow is

(a) continuously changes with time
(b) greater at M than at N
(c) greater at N than at M
(d) same at M and N

D

Question. There is a hole in the bottom of tank having water. If total pressure at bottom is 3 atm (1 atm = 105 N/m2) then the velocity of water flowing from hole is
(a) √400m/s
(b) √600m/s
(c) √60m/s
(d) None of these

A

Question. Water flows in a stream line manner through a capillary tube of radius a, the pressure difference being P and the rate flow Q. If the radius is reduced to a/2 and the pressure is increased to 2P, the rate of flow becomes
(a) 4Q
(b) Q
(c) Q/2
(d) Q/8

D

Question. In the figure, the velocity V3 will be

(a) Zero
(b) 4 ms–1
(c) 1 ms–1
(d) 3 ms–1

C

Question. Two capillary of length L and 2L and of radius R and 2R are connected in series. The net rate of flow of fluid through them will be (given rate to the flow through single capillary

A

Question. One drop of soap bubble of diameter D breaks into 27 drops having surface tension s. The change in surface energy is
(a) 2πσD2
(b) 4πσD2
(c) πsD2
(d) 8πsD2

D

Question. A capillary tube of radius r is immersed in a liquid. The liquid rises to a height h. The corresponding mass is m. What mass of water shall rise in the capillary if the radius of the tube is doubled?
(a) m
(b) 2m
(c) 3m
(d) 4m

B

Question. Two soap bubbles (surface tension T) coalesce to form a big bubble under isothermal condition. If in this process the change in volume be V and the surface area be S, then the correct relation is (P is atmospheric pressure)
(a) PV + TS = 0
(b) 3PV + 4TS = 0
(c) 3PV + TS = 0
(d) 4PV + 3TS = 0

B

Question. A body of density r’ is dropped from rest at a height h into a lake of density r where r > r’ neglecting all dissipative forces, calculate the maximum depth to which the body sinks before returning to float on the surface :

C

Question. Two liquids of densities d1 and d2 are flowing in identical capillary tubes uder the same pressure difference. If t1 and t2 are time taken for the flow of equal quantities (mass) of liquids, then the ratio of coefficient of viscosity of liquids must be

A

Question. An egg when placed in ordinary water sinks but floats when placed in brine. This is because
(a) density of brine is less than that of ordinary water
(b) density of brine is equal to that of ordinary water
(c) density of brine is greater than that of ordinary water
(d) None of these

C

Question. Two pieces of metals are suspended from the arms of a balance and are found to be in equilibrium when kept immersed in water. The mass of one piece is 32 g and its density 8 g cm–3. The density of the other is 5 g per cm3. Then the mass of the other is
(a) 28 g
(b) 35 g
(c) 21 g
(d) 33.6 g

B

Question. In a satellite moving round any planet, the gravitational force is effectively balanced. If an ice cube exists there, and it melts with passage of time, its shape will
(a) remain unchanged
(b) change to spherical
(c) become oval-shaped with long-axis along the orbit plane
(d) become oval-shaped with long axis perpendicular to orbit plane

B

Question. Figure here shows the vertical cross section of a vessel filled with a liquid of density r. The normal thrust per unit area on the walls of the vessel at the point P, as shown, will be

(a) hrg
(b) Hrg
(c) (H – h) rg
(d) (H – h) rg cosθ

C

Question. Two vessels A and B of cross-sections as shown in figure contain a liquid up to the same height. As the temperature rises, the liquid pressure at the bottom (neglecting expansion of the vessels) will

(a) increase in A, decrease in B
(b) increase in B, decrease in A
(c) increase in both A and B
(d) decrease in both A and B

A

Question. The pressure energy per unit volume of a liquid is
(a) p/P
(b) P
(c) P × P
(d) P/p

B

Question. A water tank of height 10m, completely filled with water is placed on a level ground. It has two holes one at 3 m and the other at 7 m from its base. The water ejecting from
(a) both the holes will fall at the same spot
(b) upper hole will fall farther than that from the lower hole
(c) upper hole will fall closer than that from the lower hole

A

Question. A fast train goes past way side station platform at high speed. A person standing at the edge of the platform is
(a) attracted to train
(b) repelled from train
(c) unaffected by outgoing train
(d) affected only if the train’s speed is more than the speed of sound

A

Question. A beaker with a liquid of density 1.4 g cm–3 is in balance over one pan of a weighing machine. If a solid of mass 10 g and density 8 g cm–3 is now hung from the top of that pan with a thread and sinking fully in the liquid without touching the bottom, the extra weight to be put on the other pan for balance will be
(a) 10.0 g
(b) 8.25 g
(c) 11.75 g
(d) –1.75 g

A

Question. Three tubes X, Y and Z are connected to a horizontal pipe in which ideal liquid is flowing. The radii of the tubes X, Y and Z at the junction are respectively 3 cm, 1 cm and 3 cm. It can be said

(a) the height of the liquid in the tube A is maximum.
(b) the height of liquid in the tubes Aand B is same.
(c) the height liquid in the tubes A,B and C is same.
(d) the height of the liquid in the tubes A and C is the same.

B

Question. Figure shows a capillary rise H. If the air is blown through the horizontal tube in the direction as shown then rise in capillary tube will be

(a) = H
(b) > H
(c) < H
(d) zero

B

Question. A tank has a small hole at its botom of area of cross-section a. Liquid is being poured in the tank at the rate Vm3/s, the maximum level of liquid in the container will be (Area of tank A)

B

Question. A tall cylinder is filled with viscous oil. A round pebble is dropped from the top with zero initial velocity. From the plot shown in figure, indicate the one that represents the velocity (v) of the pebble as a function of time (t) .

C

Question. A sphere of brass released in a long liquid column attains a terminial speed v0. If the terminal speed attained by sphere of marble of the same radius and released in the same liquid is nv0, then the value of n will be (Given : The specific gravities of brass, marbles and the liquid are 8.5, 2.5 and 0.8 respectively.)
(a) 5/17
(b) 17/77
(c) 11/31
(d) 17/5

B

Question. Which of the following diagrams does not represent a streamline flow?

D

Question. An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters 2.5 cm and 3.75 cm. The ratio of the velocities in the two pipes is
(a) 9 : 4
(b) 3 : 2
(c) 3: 2
(d) 2: 3

A

Question. The wetability of a surface by a liquid depends primarily on
(a) surface tension
(b) density
(c) angle of contact between the surface and the liquid
(d) viscosity

C

Question. Along a streamline,
(a) the velocity of a fluid particle remains constant
(b) the velocity of all fluid particles crossing a given position is constant
(c) the velocity of all fluid particles at a given instant is constant
(d) the speed of a fluid particle remains constant

B

Question. The angle of contact at the interface of water-glass is 0°, ethyl alcohol-glass is 0°, mercury-glass is 140° and methyliodide-glass is 30°. A glass capillary is put in a trough containing one of these four liquids. It is observed that the meniscus is convex. The liquid in the trough is
(a) water
(b) ethylalcohol
(c) mercury
(d) methyliodide

C

Question. A fluid is in streamline flow across a horizontal pipe of variable area of cross section. For this which of the following statements is correct?
(a) The velocity is minimum at the narrowest part of the pipe and the pressure is minimum at the widest part of the pipe
(b) The velocity is maximum at the narrowest part of the pipe and pressure is maximum at the widest part of the pipe
(c) Velocity and pressure both are maximum at the narrowest part of the pipe
(d) Velocity and pressure both are maximum at the widest part of the pipe

B

Question. The cylindrical tube of a spray pump has radius, R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is V, the speed of the ejection of the liquid through the holes is :
(a) VR2/nr2
(b) VR2/n3r2
(c) V2R/nr
(d) VR2/n2r2

A

Question. A certain number of spherical drops of a liquid of radius ‘r’ coalesce to form a single drop of radius ‘R’ and volume ‘V’. If ‘T’ is the surface tension of the liquid, then :

C

Question. A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 m2. Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be (rair = 1.2 kg/m3)
(a) 4.8 × 105 N, upwards
(b) 2.4 × 105 N, upwards
(c) 2.4 × 105 N, downwards
(d) 4.8 × 105 N, downwards

B

Question. Water rises to a height ‘h’ in a capillary tube. If the length of capaillary tube above the surface of water is made less than ‘h’ then :
(a) water rises upto the top of capillary tube and stays there without overflowing
(b) water rises upto a point a little below the top and stays there
(c) water does not rise at all.
(d) Water rises upto the tip of capillary tube and then starts overflowing like fountain.

A

Question. A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is

(a) 425 kg m–3
(b) 800 kg m–3
(c) 928 kg m–3
(d) 650 kg m–3

C

Question. Two non-mixing liquids of densities r and nr(n > 1) are put in a container. The height of each liquid is h. A solid cylinder of length L and density d is put in this container. The cylinder floats with its axis vertical and length pL(p < 1) in the denser liquid. The density d is equal to :
(a) {1 + (n + 1)p}r
(b) {2 + (n + 1)p}r
(c) {2 + (n – 1)p}r
(d) {1 + (n – 1)p}r