CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Fluids Quiz 13 - MCQExams.com

A book is submerged in a vessel filled with water by a spring attached to the bottom of the vessel$$.$$ In equilbrium spring is compressed$$.$$ The vessel now moves downwards with an acceleration a $$(<g).$$ The spring length$$-$$                                       
1299777_1f2e1b135b0544b29fc9320d432a9567.JPG
  • Will become zeroA
  • May increase$$,$$ decrease or remain constant
  • Will decrease
  • will increase
A cubical block is floating in a liquid with one fourth of its volume immersed in the liquid. If whole of the system accelerates upward with acceleration $$g/4$$, the fraction of volume immersed in the liquid will be
  • $$1/4$$
  • $$1/2$$
  • $$3/4$$
  • $$2/3$$
A wooden cylinder of diameter $$4r$$, height $$h$$ and density $$\rho /3$$ is kept on a hole of diameter $$2r$$ of tank, filled with liquid of density $$\rho$$ as shown in the figure.
Now level of the liquid starts decreasing slowly. When the level of liquid is at a height $${h}_{1}$$ above the cylinder the block starts moving up. At what value of $${h}_{1}$$, will the block rise?
1269952_4eed56feea82494396d3bf9de68d0076.png
  • $$4h/9$$
  • $$5h/9$$
  • $$5h/3$$
  • Remains same
Two equal spherical bodies A and B specific gravity $$1.2$$ and $$0.8$$ respectively are attached by a thin mass less rod. Now it is placed inside the water as shown in the figures. The bodies A and B are in
1227063_86229c078f514ee3af240e0f1d3ea127.png
  • stable equilibrium
  • unstable equilibrium
  • neutral equilibrium
  • information is inadequate
Water flows in a streamline manner through a capillary tube of radius a. The pressure difference being P/2 and the rate of flow is 8 cc per second. If the radius is reduced to r/2 and the pressure is increased to P, then the rate of flow becomes
  • 1 CC/S
  • 2 CC/S
  • 4 CC/S
  • 8 CC/S
Bernoulli's equation is applicable to
  • Static fluids
  • Flowing liquids
  • Energy of liquid
  • Both 1&3
An iron box is kept on the surface in the position as shown in figure if its mass is 63 kg then the pressure extend by it on the surface (value of g = m/s)  
1294925_c1eb19cd95f64c0d9eed0bf5559cfed2.PNG
  • 1.4 pa
  • 14000 pa
  • 1400 pa
  • None of these
A beaker containing a liquid is kept inside a big closed jar. If air inside jar is continuously pumped out, pressure in liquid near bottom of the liquid
  • Increases
  • Decreases
  • Remains constant
  • becomes zero
Two swimmers start a race. One who reaches the point $$C$$ first on the other bank wins the race. $$A$$ makes his strokes in a direction of $$37^{o}$$ to the river flow with velocity $$5\ km/hr$$ relative to water. $$B$$ make his strokes in a direction $$127^{o}$$ to the river flow with same relative velocity. River is flowing with speed of $$2\ km/hr$$ and is $$100\ m$$ wide. speeds of $$A$$ and $$B$$ on the ground are $$8 \ km/hr$$ and $$6 \ km/hr$$ respectively .
1360995_72015ad078454b5aba706a8626c4b70c.png
  • $$A$$ will win the race
  • $$B$$ will win the race
  • the time taken by $$A$$ to reach the point $$C$$ is $$165$$ seconds
  • the time taken by $$B$$ to reach the point $$C$$ is $$150$$ seconds
Two equal drops are falling through air with a steady velocity of 5 cm/s. if the drops coalence, the new terminal velocity will be
  • $$ 5 \times 2 cm $$
  • $$ 5 \times \sqrt 2 cm/s $$
  • $$ 5 \times (4)^{1/3} cm/s $$
  • $$ 5 / \sqrt 2 cm/s $$
A metal ball is being weighed in a liquid whose temperature is raised continuously. Then the apparent weight of the ball :
  • remain unchnaged
  • increases
  • decreases
  • changes erratically
When a pipe of the radius of cross- section '$$r$$' is arranged at a height h horizontally the jet of from it touches at a distance '$$x$$' from a point just below the pipe on the ground. if the pipe is closed partly such that its radius of cross-section becomes $$r/2$$ and it is arranged at a height $$4h$$ then the horizontal distance at which waterfall increases by
  • $$8x$$
  • $$2x$$
  • $$7x$$
  • $$x/2$$
Dry air at one atmospheric pressure is suddenly compressed so that its volume becomes one-fourth. Its pressure will become - ($$\gamma =1.5$$)
  • $$4$$ atm
  • $$8$$ atm
  • $$16$$ atm
  • $$32$$ atm
A hole is made a 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
Two tubes of radii $$r_1$$ and $$r_2$$, and length $$l_1$$ and $$l_2$$ respectively, are connected in series and a liquid flows through each of them in streamline conditions. $$P_1$$ and $$P_2$$ are pressure differences across the two tubes. If $$P_2$$ is $$4P_1$$ and $$l_2$$ is $$\frac {l_1}{4}$$, then the radius $$r_2$$ will be equal to :
  • $$2{r_1}$$
  • $$4{r_1}$$
  • $${r_1}$$
  • $$\frac {r_1}{2}$$
When a ball is dropped from a height of $$19.6$$ m above a liquid surface whose density is double of ball. Find the depth upto which the ball falls in liquid. 
  • $$9.8$$ m
  • $$19.6$$ m
  • $$29.4$$ m
  • $$4.9$$ m
A hole is made at the bottom of the tank filled with water (density $$1000 kg/m^3)$$. If the total pressure at the bottom of the tank is 3 atm (1 atm$$=10^5 N/m^2$$).
  • $$\sqrt{200} m/s$$
  • $$\sqrt{400} m/s$$
  • $$\sqrt{600} m/s$$
  • $$\sqrt{800} m/s$$
Consider a wooden block immersed in a beaker containing water. If the beaker now starts accelerating upwards then :


1385240_f35d7c97c9b2499bb760aceae2b6d3d9.jpg
  • Tension in the string will increase
  • Tension in the string will decrease
  • Tension in the string will remain unchanged
  • Data insufficient
A block of wood of length $$50\ cm$$ and area of cross-section $$10\ cm^{2}$$, floats in water with $$\dfrac{3}{5}$$ of its lengths above water. Calculate weight of wood 
  • $$200\ gf$$
  • $$300\ gf$$
  • $$400\ gf$$
  • $$500\ gf$$
A tube of $$1 $$mm bore is dipped into a vessel containing a liquid of density $$\rho = 800\ kg $$$${ m }^{ -3 }$$ and of surface tension , $$S = 49\times { 10 }^{ -3 }$$ $$nm^{ -1 }$$ and angle of contact, $$\theta ={ 0  }^{ \circ  }$$. The tube is held inclined to the vertical at an angle of $${ 60 }^{ \circ  }$$. Find the height to which the liquid can rise and the length which the liquid will occupy in the tube. 
  • 1.5 cm, 5 cm
  • 3.5 cm, 5 cm
  • 4 cm, 2.5 cm
  • 2.5 cm, 5 cm
A $$0.50\ L$$ container is occupied by nitrogen at a pressure of $$800\ torr$$ and a temperature of $$0^{o}C$$. The container can only withstand a pressure of $$3.0\ atm$$. What is the highest temperature $$(^{o}C)$$ to which the container may be heated?
  • $$505$$
  • $$450$$
  • $$625$$
  • $$500$$
The mercury columns in a manometer are given as 2$$\mathrm { cm }$$ and 12$$\mathrm { cm }$$ respectively. Specific gravity of mercury is13.The gauge pressure is pressure is $$\left( g = 10 \mathrm { m } / \mathrm { s } ^ { 2 } \right)$$
  • $$13.6 \times 10 ^ { 3 } N / m ^ { 2 }$$
  • $$13.6N / m ^ { 2 }$$
  • $$1.36 \times 10 ^ { 3 } N / m ^ { 2 }$$
  • $136$N / m ^ { 2 }$$
Water enters a horizontal pipe of non uniform cross section with a velocity
of $$0.4 \mathrm { ms } ^ { - 1 }$$ and leaves the other end with a velocity of 0.6$$\mathrm { ms } ^ { - 1 } .$$ Pressure of water at the first end is $$1500 \mathrm { Nm } ^ { - 2 } ,$$ then pressure at the other end is 
  • 1000$$\mathrm { Nm } ^ { - 2 }$$
  • 1200$$\mathrm { Nm } ^ { - 2 }$$
  • 1400$$\mathrm { Nm } ^ { - 2 }$$
  • 1600$$\mathrm { Nm } ^ { - 2 }$$
The area of cross section of the wider tube shown in figure is 900 $$
\mathrm{cm}^{2}
 $$. If the boy standing on the piston weighs 45 kg, the difference in the levels of water in the two tubes.


1361615_04379b61568b4360a0b088174427e6ab.png
  • 50 cm
  • 25cm
  • 75 cm
  • 100 cm
When a venturimeter is used in an inclined position, it will show
  • same reading
  • higher reading
  • lower reading
  • depends on viscosity of liquid
Two vessels A and B of different shapes have the same base area and are filled with water up to the same height h (see figure). The force exerted by water on the base is $$F_{A}$$ for vessel A and $$F_{B}$$ for vessel B. The respective weights of the water filled in vessels are $$W_{A}$$ and $$W_{B}$$ . Then

1397508_48344666f444452c8a9167849f5bf78c.png
  • $$F_{A}>F_{B}  ;\ W_{A}>W_{B}$$
  • $$F_{A}=F_{B}  ;\ W_{A}>W_{B}$$
  • $$F_{A}=F_{B}  ;\ W_{A}<W_{B}$$
  • $$F_{A}>F_{B}  ;\ W_{A}=W_{B}$$
A solid sphere of density $$\eta (>1)$$ times lighter than water is suspended in a water tank by a string tied to its base as shown in fig. If the mass of the sphere is m then the tension in the string is given by 
1401314_7eb911d5310d46188ac095cdf29e9c30.png
  • $$(\frac{\eta -1}{\eta })mg$$
  • $$\eta$$ mg
  • $$\frac{mg}{\eta }$$
  • $$(\eta-1) mg$$
The height of water level in a tank is 'H'.  The horizontal range of water straem coming out of hole at a depth of H/4, from upper water level will be
  • $$

    \frac{\sqrt{3} H}{2}

    $$
  • $$

    \frac{2 \mathrm{H}}{\sqrt{3}}

    $$
  • $$

    \frac{H}{\sqrt{3}}

    $$
  • $$

    \sqrt{3} \mathrm{H}

    $$
A tank $$5\ m$$ high is half filled with water and then is filled to the top with oil of density $$0.85\ g/cm^ {2}$$. The pressure at the bottom of the tank, due to these liquids, is
  • $$1.85\ gf/cm^ {2}$$
  • $$89.25\ gf/cm^ {2}$$
  • $$462.5\ gf/cm^ {2}$$
  • $$500\ gf/cm^ {2}$$
For the arrangement shown in the figure, the force at the bottom of the vessel is
1400669_77a202ffcc344dcfa0bccdcb5dcdf4dd.PNG
  • 200 N
  • 100 N
  • 20 N
  • 2 N
An ideal fluid is flowing in steady state from section A to B through a pipe in vertical plane as shown. Select incorrect statement. q
1412132_2a33cc0be8844622955aaf2b8c1eb22b.jpg
  • Total energy per unit volumes is same at both sections A and B
  • Incoming rate at A is equal to outgoing rate at B
  • Loss in kinetic energy of the fluid is equal to gain in potential energy from section A to B
  • Flow of fluid from A to B is laminar flow
An incompressible fluid flows steadily through a cyindrical pipe which has radius 2$$R$$ at point $$A$$ an radius $$R$$ at point $$B$$ further along the flow direction. If the velocity at point $$A$$ is $$v$$ , its velocity at point will be
  • 2$$v$$
  • $$\mathbf { v }$$
  • $$\mathrm { v } / 2$$
  • 4$$\mathrm { v }$$
The ratio of forces exerted by the larger piston to the smaller piston is 
  • 1 : 144
  • 1 : 72
  • 144 : 1
  • 72 : 1
The minimum horizontal acceleration of the container so that the pressure at the point A of the container becomes atmospheric is (the tank is of sufficient height)


1439062_0943d07991844e36b1574bc6c9f415c7.jpg
  • $$\frac { 3 } { 2 } g$$
  • $$\frac { 4 } { 3 } g$$
  • $$\frac { 4 } { 2 } g$$
  • $$\frac { 3 } { 4 } g$$
If pressure at half the depth of a lake is equal to $$\dfrac{2}{3}rd$$ of the pressure at the bottom of the lake. Then what is the depth of the lake 
  • $$10$$ $$\mathrm { m }$$
  • $$20$$ $$\mathrm { m }$$
  • $$60$$ $$\mathrm { m }$$
  • $$30$$ $$\mathrm { m }$$
Which among the following is correct in terms of liquid pressure at points A,B and C?
[where $$\rho =  $$ density of liquid]
1434032_3b28a74ca7e1497b8156b9c243db3b3f.png
  • $$P_A=P_B=P_C=\rho gH$$
  • $$P_A > P_B > P_C$$
  • $$P_A=P_B=P_C=2 \rho gH$$
  • $$P_A > P_B = P_C$$
A water drop of radius $$1.5\ mm$$ is falling from height $$\ 1 \ km$$ having drag constant $$0.5$$ density of water drop is $$1000 kg/m^{ 3 }$$ and density of air is $$1.29\ kg/m^{ 3 }$$.Find its terminal velocity.
  • $$8.7 m/s$$
  • $$7.8 m/s$$
  • $$5.6 m/s$$
  • $$4.3 m/s$$
A massive conical flask filled with liquid is kept on a table in a vacuum. The force exerted by the liquid on the base of the flask is $$ W_{1} $$. The force exerted by the flask on the table is $$  W_{2}  $$.

1425805_f6df3e0524ba4602818785cf72a3420f.png
  • $$W_{1}=W_{2}$$
  • $$W_{1}\gt W_{2}$$
  • $$W_{1}\lt W_{2}$$
  • The force exerted by the liquid on the walls of the flask is $$ \left(W_{1}-W_{2}\right) $$
A hemispherical bowl of radius  "R" is placed on a flat horizontal surface on its circular base. There is a small hole at the top of the inverted bowl. Through the hole, a liquid of density " P" is poured slowly. When the bowl just gets filled, water starts flowing on to the table from its base. The bowl is 
1406548_7d67f26c2de44d06a0a36ff7ec1ecd2c.png
  • $$ \frac { \pi { R }^{ 3 }P }{ 2} $$
  • $$ \frac { \pi { R }^{ 3 }P }{ 3} $$
  • $$ \frac { \pi { R }^{ 3 }P }{ 4} $$
  • $$\frac { \pi { R }^{ 3 }P }{ 1} $$
A hotel cleaner wipes out a wet (water) table using a smooth plastic sheet with a speed of 10 by applying a tangential force of 25 dynes. The layer of liquid between the plastic sheet and the table is 0.8 mm thick. If there is a spill over of  oil of viscosity o.84 poise on a dry table. What is the required force to maintain the same speed. Assume that all other parameters remain same Viscosity of water is 0.01 poise
  • 2100 dynes
  • 2200 dynes
  • 2300 dynes
  • 2400 dynes
The diameter of two pistons of hydraulic press are $$0.1 m$$ and $$0.6 m$$ respectively. Advantage of the hydraulic press assuming effort is applied directly on pump plunger.
  • $$6$$
  • $$36$$
  • $$\dfrac { 1 }{ 6 } $$
  • $$\dfrac { 1 }{ 36 } $$
Which of the following is NOT the characteristic of turbulent flow ?
  • Velocity more than the critical velocity
  • Velocity less than the critical velocity
  • Irregular flow
  • Molecules crossing from one layer to another
A wire of length 'l' meters, made of material of specific gravity 8 is floating horizontally on the surface of water. If it is not wet by water, the maximum diameter of the wire (in milli meters) upto which it can continue to float is (surface tension of water is $$T = 70\times { 10 }^{ -3 }{ Nm }^{ -1 })$$ 
  • 1.5
  • 1.1
  • 0.80
  • 0.55
A rain drop of radius $$1.5 mm$$, experiences a drag force $$F =$$ $$12\times 10^{-5}\times v \:N$$, while falling through air from a height $$2 km$$, with a velocity $$v$$. The terminal velocity of the rain drop will be nearly (use $$g=10 m/s^2)$$ : 
  • $$200 m/s$$
  • $$60 m/s$$
  • $$7m/s$$
  • $$3 m/s$$
Water is flowing through two horizontal pipes of different radii which are connected together. In the first pipe speed of water is 4 $${ ms }^{ -1 }$$ and the pressure is $$1.25\times { 10 }^{ 4 }{ Nm }^{ -2 }$$. Then pressure of water in the second pipe is 
( radii of those pipes are in the ratio 1:2)
  • $$0.5\times { 10 }^{ 4 }{ Nm }^{ -2 }$$
  • $$0.75\times { 10 }^{ 4 }{ Nm }^{ -2 }$$
  • $$1\times { 10 }^{ 4 }{ Nm }^{ -2 }$$
  • $$2\times { 10 }^{ 4 }{ Nm }^{ -2 }$$
A glass ball is dropped into a long cylinder full of water. The terminal velocity of the ball depends on 
  • Radius of the ball
  • Height of the cylinder
  • Hydrostatic pressure
  • Diameter of the cylinder
The work done by pressure in forcing $$2{ m }^{ 3 }$$ of water through a pipe of radius $$1 m$$, if the pressure difference across a pipe is $${ 10 }^{ 5 }$$ Pa is
  • $$3\times \quad { 10 }^{ 6 }J$$
  • $$2\times \quad { 10 }^{ 5 }J$$
  • $$4\times \quad { 10 }^{ 6 }J$$
  • $$0.2\times \quad { 10 }^{ 3 }J$$
Two glass balls of radii r and 2r are dropped in air. The terminal velocity of the ball with radius r is 1 $$cms^{-1}$$.. That of the other will be 
  • 0.5 $$cms^{-1}$$.
  • 1 $$cms^{-1}$$.
  • 2 $$cms^{-1}$$.
  • 4 $$cms^{-1}$$.
Why the dam of water reservoir is thick at the bottom ?
  • Quantity of water increases with depth
  • Density of water increase with depth
  • Pressure of water increases with depth
  • Because of some reason other than those mentioned above
A spherical drop of water has 1$$\mathrm { mm }$$ radius. If the surfacetension of the water is $$50 \times 10 ^ { - 3 } \mathrm { N } / \mathrm { m }$$ , then the differenceof pressure between inside and outside the spherical dropis:
  • 25$$\mathrm { N } / \mathrm { m } ^ { 2 }$$
  • 10000$$\mathrm { N } / \mathrm { m } ^ { 2 }$$
  • 100$$\mathrm { N } / \mathrm { m } ^ { 2 }$$
  • 50$$\mathrm { N } / \mathrm { m } ^ { 2 }$$
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