CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Fluids Quiz 10 - MCQExams.com

The angle of contact between glass and mercury is :
  • $$
    0^{0}
    $$
  • $$
    30^{0}
    $$
  • $$
    90^{0}
    $$
  • $$
    135^{0}
    $$
Anomalous expansion of water is demonstrated by using
  • Jolly's apparatus
  • Hopes apparatus
  • Regnaults apparatus
  • Specific apparatus
A steel ball is dropped in a viscous liquid. The distance of the steel ball from the top of the liquid is shown below. The terminal velocity of the ball is closest to : 
1688342_d84c8133d2bc4087a167c2cba7ac6b9d.png
  • $$0.26 m/s$$
  • $$0.33 m/s$$
  • $$0.45 m/s$$
  • $$0.21 m/s$$
The terminal velocity of solid sphere of radius $$0.1$$ m moving in air in vertically downward direction, is: $$(\eta =1.8\times 10^{-5} Ns/m^2$$, density of sphere $$=1000 kg/m^3$$ and $$g=10 m/s^2$$)
  • $$2\times 10^5$$ m/s
  • $$1.2\times 10^2$$ cm/s
  • $$4\times 10^2$$ cm/s
  • None of these
A container of height $$10\ cm$$ is filled with water. There is a hole at bottom. Find the pressure difference between points $$A$$ & $$B$$.

1631895_b63d67b3bda444059501c638027629c7.jpg
  • $$1000\ Pa$$
  • Zero
  • $$1\ Pa$$
  • $$100\ Pa$$
How many cylinders of hydrogen at atmospheric pressure are require to fill a balloon whose volume is $$500\ m^3$$, if hydrogen is stored in cylinder of volume $$0.05\ m^3$$ at an absolute pressure of $$15\times 10^5 \ Pa$$?
  • $$700$$
  • $$675$$
  • $$605$$
  • $$710$$
A solid sphere falls with a terminal velocity of $$20m/s^{-1}$$ in air. If it is allowed to fall in vacuum 
  • terminal velocity will be $$20 m/s^{-1}$$.
  • terminal velocity will be less than $$20 m/s^{-1}$$
  • terminal velocity will be more than $$20 m/s^{-1}$$
  • there will be no terminal velocity
At $$20^o$$C, to attain the terminal velocity how fast will an aluminium sphere of radii $$1$$ mm fall through water? [Assume flow to be laminar flow and specific gravity $$(Al)=2.7$$, $$\eta_{water}=8\times 10^{-4}$$Pa]
  • $$5$$ m/s
  • $$4.7$$ m/s
  • $$4$$ m/s
  • $$2$$ m/s
A flask containing air at $$27^oC$$ at atmospheric pressure is croked up. A pressure of $$2.5\ atm$$, inside the flask would force the rock out. The temperature at which it will happen is :
  • $$67.5^oC$$
  • $$577^oC$$
  • $$670^oC$$
  • $$750\ K$$
A block of wood is floating in water in a closed vessel as shown in the figure. The vessel is connected to an air pump. When more air is pushed into the vessel, the block of wood floats with (neglect compressibility of water)
1737586_48a2a3a48556416485699cc9f1b28ed7.JPG
  • larger part in the water
  • smaller part in the water
  • same part in the water
  • at some instant it will sink
A hole is made at the bottom of a tank filled with water $$\left(density={10}^{3}kg/m^{3}\right)$$. If the total pressure at the bottom of the the tank is $$3atm\left(1atm=10^{5}{N/m}^{2}\right)$$, then the velocity of efflux is
  • $$\sqrt{400}m/s$$
  • $$\sqrt{200}m/s$$
  • $$\sqrt{600}m/s$$
  • $$\sqrt{500}m/s$$

1738970_5d9a1cb60d644997826dc4f153022716.JPG
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
Find the force acting at the pivoted end of the rod in terms of mass $$m$$ of the rod.
  • $$\left(\sqrt{2}-1\right)mg$$
  • $$\left(\sqrt{2}+1\right)mg$$
  • $$\left(\sqrt{3}+1\right)mg$$
  • $$\left(\sqrt{2}+3\right)mg$$
A jet of water having velocity $$=10\ m/s$$ and stream cross-section $$=2\ cm^2$$ hits a flat plate perpendicularly, with the water splashing out parallel to plate. The plate experiences a force of :
  • $$40\ N$$
  • $$20\ N$$
  • $$8\ N$$
  • $$10\ N$$
A tube $$1\ cm^2$$ in cross-section is attached to the top of a vessel $$1\ cm$$ high and cross- section $$100\ cm^2$$. Water fills the system upto a height of $$100\ cm$$ from the bottom of the vessel. The force exerted by the liquid at the bottom of the vessel is : 
1745819_88965f7d173c4db7a569675dcb758d6b.png
  • $$1000\ N$$
  • $$990\ N$$
  • $$900\ N$$
  • $$100\ N$$
When an iceberg floats in sea water, only one tenth of its volume is inside the sea water. 
  • True
  • False
For a surface molecule
  • the net force on it is zero
  • there is a net downward force
  • the potential energy is less than that of a molecule inside
  • the potential energy is more than that of a molecule inside
A ball whose density is 0.4 × 103 kg/m falls into water from a height of 9 cm . To what depth does the ball sink
  • 9 cm
  • 6 cm
  • 4.5 cm
  • 2.25 cm
The atmospheric pressure at earth surface is$$ P_{1}$$ and inside mine is $$ P_{2}.$$ They are related as:
  • $$ P_{1} = P_{2}.$$
  • $$ P_{1} > P_{2}.$$
  • $$ P_{1} < P_{2}.$$
  • $$ P_{2} $$ = 0
From the adjacent figure, the correct observation is

                                                                                            [ KCET 2005 ]
1813430_7114e79def674f6caa9bcd60f617281f.png
  • The pressure on the bottom of tank (a) is greater than at the bottom of (b).
  • The pressure on the bottom of the tank (a) is smaller than at the bottom of (b).
  • The pressure depend on the shape of the container
  • The pressure on the bottom of (a) and (b) is the same
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

  • $$2p$$
  • $$8p$$
  • $$4p$$
  • $$7p$$
A hydraulic lift is designed to lift heavy objects of maximum mass $$2000 kg$$. The area of cross-section of piston carrying the load is $$2.25 \times 10^{-2} m^2$$. What is the maximum pressure the smaller piston would have to bear?
  • $$0.8711 \times 106 \ N/m^2$$
  • $$0.5862 \times 107 \ N/m^2$$
  • $$0.4869 \times 105 \ N/m^2$$
  • $$0.3271 \times 104 \ N/m^2$$
A triangular lamina of area $$ A $$and height $$ h $$ is immersed in a liquid of density $$\rho$$ in a vertical plane with its base on the surface of the liquid. The thrust on the lamina is

  • $$\dfrac{1}{2}A\rho gh$$
  • $$\dfrac{1}{3}A\rho gh$$
  • $$\dfrac{1}{6}A \rho gh$$
  • $$\dfrac{2}{3}A \rho gh$$
Angle of contact for a glass tube dipped in mercury is obtuse. True / False.
  • True
  • False
A water supply maintains a constant rate of flow for water in a hose. You want to change the opening of the nozzle so that water leaving the nozzle will reach a height that is four times the current maximum height the water reaches with the nozzle vertical. To do so, should you
  • decrease the area of the opening by a factor of $$16$$
  • decrease the area by a factor of $$8$$
  • decrease the
    area by a factor of $$4$$
  • decrease the area by a factor of $$2$$
  • give up because it cannot be done?
Figure shows aerial views from directly above two dams. Both dams are equally wide (the vertical dimension in the diagram) and equally high (into the page in the diagram). The dam on the left holds back a very large lake, and the dam on the right holds back a narrow river. Which dam has to be built more strongly?
1866046_95da79611eb845ebaa4cbf21443ba99e.png
  • the dam on the left
  • the dam on the right
  • both the same
  • cannot be predicted
A boat travelling at $$6 m/s$$ in sea water has a $$250 mm$$ diameter propeller that discharges the water at a velocity of $$12 m/s$$. Given that the density of seawater is $$1030 \mathrm{k}\mathrm{g}/\mathrm{m}^{3}$$. The effect of propeller hub is negligible. The magnitude of thrust produced $$F$$ is (in $$N$$)

43190.png
  • $$1030$$
  • $$2730$$
  • $$4660$$
  • $$980$$
Ratio of area of hole to beaker is $$ 0.1$$ Height of liquid in beaker is $$3m$$, and hole is at the height of $$52.5 cm$$ from the bottom of beaker, find the square of the velocity of liquid coming out from the hole:
  • $$50 \ (m/s)^2$$
  • $$50.5 \ (m/s)^2$$
  • $$51 \ (m/s)^2$$
  • $$42 \ (m/s)^2$$
A wide vessel with a small hole at the bottom is filled with two liquids. The density and height of one liquid are $$ {\rho}_{1}\   and\   {h}_{1} $$ and that of the other are $$ {\rho}_{2}$$ and $${h}_{2}$$. (Given $$ {\rho}_{1} > {\rho}_{2} ) $$. The velocity of liquid coming out of the hole is :
  • $$ v = \sqrt{2g({h}_{1} + {h}_{2})} $$
  • $$ v = \sqrt{2g({h}_{1}{\rho}_{1} + {h}_{2}{\rho}_{2})/ ({\rho}_{1} + {\rho}_{2})} $$
  • $$ v = \sqrt{2g[{h}_{1} + \dfrac{{h}_{2}{\rho}_{2}}{{\rho}_{1}}]}$$
  • $$ v = \sqrt{2g[\dfrac{{h}_{1}{\rho}_{1}}{{\rho}_{2}} + {h}_{2}]}$$
Which of the following is not possible ?
Figure shows a pilot-static tube to measure air speed. (attached to a manometer)
The manometer shows a difference in levels $$9 mm$$. lt contains water of density 998 $$\mathrm{k}\mathrm{g}/\mathrm{m}^{3}$$. The density of air is 1.2 $$\mathrm{k}\mathrm{g}/\mathrm{m}^{3}$$. The gravitational field strength is 9.81 m/s$$^2$$. The agreement between the measured and calculated values of air speed is not very good so that $$V_{calibrated}=Cv_{air}$$ where  C is called calibration coefficient. Then:

43923_90ad2a19214648eba703a6975183df89.png
  • the pressure difference is $$88 Pa$$ (nearly).
  • the coefficient C is due to fact that even air is slightly viscous causing some turbulence by the hypodermic needles.
  • in order to apply Bernoulli equation, the flow need not be streamline non-viscous and incompressible.
  • if calibrated flow meter records air speed of $$8.8 m/s$$, the factor C is $$0.73.$$
The difference in the pressure between the air just over the wing $$\mathrm{P}_{1}$$ and that under the wing $$\mathrm{P}_{2}$$  is:

43926_80fc72bbf3384a2e824f61b66b4c3ae0.png
  • $$2.8\times 10^{3}$$ Pa
  • $$0.723\times 10^{2}$$ Pa
  • $$1.46\times 10^{4}$$ Pa
  • Zero
The hydraulic press shown in the figure is used to raise the mass $$m$$ through a height of $$0.05 cm$$ by performing $$500 J$$ of work at the small piston. The diameter of the large piston is 10 cm while that of the smaller one is $$2 cm.$$ The mass $$M$$ is
25031_8666640829e74cf599830b37c7468814.png
  • $$10^{4} kg$$
  • $$10^{3} kg$$
  • $$100 kg$$
  • $$10^{5}kg$$
Bantu slips into a large lake and he doesn't know swimming. But he is a great fan of Superman. He shouted for help remembering Superman. As usual, Superman arrives on the top of a cliff and, due to some reason, Superman lost his flying power immediately after arrival on cliff. Due to shortage of time, somehow, Superman manages a strong and long straw and decided to drink whole water of lake to save Bantu.(Data:Atmospheric pressure $$=1.2 \times 10^{5} Pa, g=10m/s^{2}$$, density of water$$= 1000kg/m^{3})$$ Assume Superman has infinite power and ability to drink whole water. Which of the following statements is/are true?
(1) Superman cannot save Bantu by this way.
(2) Superman can drink some water but not whole water.
(3) Superman will save Bantu by drinking whole water.

71871.jpg
  • Only (1) & (2)
  • Only (3)
  • Only (1)
  • All (1), (2) & (3) are wrong
Equal volumes of two immiscible liquids of densities $$\delta $$ and 3$$\delta $$ are filled in a vessel. Two small holes are punched at depth $$h/3$$ and $$4h/3$$ from upper surface of lighter liquid. If $$V_{1} $$ and $$ V_{2}$$ are velocities of efflux at these two holes, then $$V_{1}/V_{2}$$ is :

73257.jpg
  • $$\dfrac{1}{2}$$
  • $$\dfrac{1}{\sqrt{2}}$$
  • $$\dfrac{1}{2\sqrt{2}}$$
  • $$\dfrac{1}{4}$$
Water is filled upto height H units in a tank placed on the ground and whose side walls are vertical. A hole is made in one of the vertical wall such that the emerging stream of water strikes the ground at the maximum range. If the level in the tank is changing at the rate of R units per second, at that instant the rate at which range will be changing will be:
  • R/2 units per second
  • R units per second
  • 2R units per second
  • Zero
A tank is filled up to a height 2H with a liquid and is placed on a platform of height H from the ground. The distance x from the ground where a small hole is punched to get the maximum range R is
119441.png
  • H
  • 1.25 H
  • 1.5 H
  • 2 H

In a container water is filled upto certain height with a hole at its bottom. A bird is coming towards free surface of the liquid with velocity $$\overrightarrow V_b=(12\hat i-10\hat j)m/s$$ and fish is rising upwards with velocity $$\overrightarrow V_{fish}(3\hat j)m/s$$. 
The speed of bird as seen by fish under normal incidence condition at the moment when water level in container is $$20 m$$ from its bottom is: (given hole area $$=1 cm^2$$; surface area of liquid $$=20 cm^2)$$

75895.jpg
  • $$20 m/s$$
  • $$40 m/s$$
  • $$10 m/s$$
  • $$12 m/s$$
A long capillary glass tube of uniform diameter of $$1mm$$ is filled completely with water and then held vertically in air. It is now opened at both ends. Find the length of the water column remaining in the glass tube. Surface tension of water is $$0.075 N/m.$$ $$(g=10m/s^2$$ and density of water is $$10^3 kg/m^3)$$:
  • Zero
  • 1.5 cm
  • 3 cm
  • 6 cm
In the figure, the cross-sectional area of the smaller tube is $$a$$ and that of the larger tube is $$2a$$. A block of mass $$m$$ is kept in the smaller tube having the same base area $$a$$, as that of the tube. The difference between water levels of the two tubes is
119533.png
  • $$\dfrac {P_0}{\rho g}+\dfrac {m}{a\rho}$$
  • $$\dfrac {P_0}{\rho g}+\dfrac {m}{2a\rho}$$
  • $$\dfrac {m}{a\rho}$$
  • $$\dfrac {m}{2\rho a}$$
A capillary tube with inner cross-section in the form of a square of side a is dipped vertically in a liquid of density $$ \rho $$ and surface tension $$ \sigma $$ which wet the surface of capillary tube with angle of contact $$ \theta $$. The approximate height to which liquid will be raised in the tube is : (Neglect the effect of surface tension at the corners of capillary tube)
  • $$ \dfrac{2\sigma cos\theta }{a\rho g} $$
  • $$ \dfrac{4\sigma cos\theta }{a\rho g} $$
  • $$ \dfrac{8\sigma cos\theta }{a\rho g} $$
  • None of these
The figure shows a crude type of atomizer. When bulb A is compressed, air flows swiftly through tube BC causing reduced pressure in the particles of the vertical tube. The liquid rises in the tube, enters 
BC and is sprayed out. If the pressure in the bulb is $$P_a+P$$, where $$P$$ is the gauge pressure and
$$P_a$$ is the atmospheric pressure, $$v$$ is the speed of air in BC, find how large would $$v$$ need to be to cause the liquid to rise to BC. 
(Density of air $$=1.3 kg/m^3$$.)

119678_d6afeee61ea64763aeebd824d41735a0.png
  • $$\sqrt{\dfrac {P+\rho gh}{ {0.65}}}$$
  • $$\dfrac {Ph\rho g}{\sqrt {0.65}}$$
  • $$\dfrac {P\sqrt {h\rho g}}{0.65}$$
  • $$\dfrac {P}{h\rho g\sqrt {0.65}}$$
In a cylindrical water tank here are two small holes Q and P on the wall at a depth of $$h_1$$ from the upper level of water and at a height of $$h_2$$ 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 $$h_1$$ and $$h_2$$ is
119559.png
  • $$1$$
  • $$2$$
  • $$> 1$$
  • $$< 1$$
A hole is made at the bottom of a tank filled with water (density $$=10^3 kg/m^3)$$. If the total pressure at the bottom of the tank is $$3 atm$$ ($$1 atm=10^5 N/m^2$$), then the velocity of efflux is
  • $$\sqrt {400}m/s$$
  • $$\sqrt {200}m/s$$
  • $$\sqrt {600}m/s$$
  • $$\sqrt {500}m/s$$
A cylindrical vessel of $$90\ cm$$ height is kept filled up to the brim. It has four holes $$1, 2, 3$$ and $$4$$ which are, respectively, at heights of $$20\ cm,\ 30\ cm,\ 40\ cm$$ and $$50\ cm$$ from the horizontal floor $$PQ$$. The water falling at the maximum horizontal distance from the vessel comes from:
119709_a0aa9dc7472e447ea62462d586126611.png
  • hole number $$4$$
  • hole number $$3$$
  • hole number $$2$$
  • hole number $$1$$
Equal volume of two immiscible liquids of densities $$\rho$$ and $$2\rho$$ are filled in a vessel as shown in the figure. Two small holes are punched at depths h/2 and 3h/2 from the surface of lighter liquid. If $$v_1$$ and $$v_2$$ are the velocities of efflux at these two holes, then $$v_1/v_2$$ is:
119554_311012478b574ba7a2381fa2a62e59b9.png
  • $$\displaystyle\frac {1}{2\sqrt 2}$$
  • $$\displaystyle\frac {1}{2}$$
  • $$\displaystyle\frac {1}{4}$$
  • $$\displaystyle\frac {1}{\sqrt 2}$$

Figure shows a cylindrical vessel of height $$90 cm$$ filled up to the brim. There are four holes in the vessel as shown. The liquid falling at maximum horizontal distance from the vessel would come from
119771.png
  • hole 1
  • hole 2
  • hole 3
  • hole 4

A cylindrical vessel of a very large cross-sectional area is containing two immiscible liquids of density $$\rho_1=600 kg/m^3$$ and $$\rho_2=1200 kg/m^3$$ as shown in the figure.
A small hole having cross-sectional area $$5 cm^2$$ is made in right side vertical wall as shown. Take atmospheric pressure as $$p_0=10^5 N/m^2, g=9.8m/s^2$$. For this situation, mark out the correct statements(s). (Take cross-sectional area of the cylindrical vessel as $$1000 cm^2$$. Neglect the mass of the vessel)
119752_702c70ee242f439ebeb08f36421cd713.png
  • If the surface on which the vessel is placed is smooth, then a rightward force of magnitude 2N is to be applied on the vessel to maintain its static equilibrium.
  • If the surface on which the vessel is placed is smooth, then no force is needed to maintain its static equilibrium.
  • If the surface on which the vessel is placed is rough $$(\mu=0.04)$$, then the minimum force (horizontal) needed to be applied on the vessel to maintains its static equilibrium is zero.
  • If the surface on which the vessel is placed is rough ($$\mu=0.04$$), then the maximum force (horizontal) needed to be applied on the vessel to maintain its static equilibrium is 19.8 N.
A tank in filled with water of density $$10^3 kg/m^3$$ and oil of density $$0.9\times 10^3 kg/m^3$$. The height of water layer is $$1 m$$ and that of the oil layer is $$4 m$$. The velocity of efflux from an opening in the bottom of the tank is
  • $$\sqrt {85}m/s$$
  • $$\sqrt {88}m/s$$
  • $$\sqrt {92}m/s$$
  • $$\sqrt {98}m/s$$
A cylindrical vessel contains a liquid of density $$\rho$$ up to height h. The liquid is closed by a piston of mass $$m$$ and area of cross section $$A$$. There is a small hole at the bottom of the vessel. The speed $$v$$ with which the liquid comes out of the hole is
119548.png
  • $$\sqrt {2gh}$$
  • $$\sqrt {2\left (gh+\frac {mg}{\rho A}\right )}$$
  • $$\sqrt {2\left (gh+\frac {mg}{A}\right )}$$
  • $$\sqrt {2gh+\frac {mg}{A}}$$
0:0:1


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