CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Fluids Quiz 2 - MCQExams.com

The correct assumption(s) made to perform a venturi-meter experiment is(are):
  • that Bernoulli's theorem holds good
  • that equation of continuity is maintained
  • that the fluid used is highly incompressible
  • that all of the above are true
The height up to which water will rise in a capillary tube will be 
  • Minimum when water temperature is $$4^{\circ}C$$
  • Maximum when water temperature is $$4^{\circ}C$$
  • Maximum when water temperature is $$0^{\circ}C$$
  • Minimum when water temperature is $$0^{\circ}C$$
For a liquid which is rising in a capillary, the angle of contact is
  • Obtuse
  • Acute
  • $$180^o$$
  • $$90^o$$
A liquid is allowed to flow in a tube of truncated cone shape. Identify correct statement from the following.
  • The speed is high at the wider end and low at the narrow end
  • The speed is low at the wider end and high at the narrow end
  • The speed is same at both ends in a stream line flow
  • The liquid flows with uniform velocity in the tube
The gauge pressure of $$3 \times 10^5$$ N/m$$^2$$ must be maintained in the main water pipes of a city. How much work must be done to pump $$50,000$$ m$$^3$$ of water at a pressure of $$1.0 \times 10^5$$ N/m$$^2$$ -
  • $$10^{11}$$ J
  • $$10^{10}$$ J
  • $$10^{9}$$ J
  • $$10^{8}$$ J
When two capillary tubes of different diameters are dipped vertically, the rise of the liquid is :
  • same in both the tubes
  • more in tube of larger diameter
  • less in the tube of smaller diameter
  • more in the tube of smaller diameter
Two drops of the same radius are falling through air with a steady velocity of 5 cm/s. If the two drops coalesce, the terminal velocity would be
  • $$10 cm/s$$
  • $$2.5 cm/s$$
  • $$5(4)^{1/3} cm/s$$
  • $$5(3)^{1/3} cm/s$$
A drop of mercury of radius $$2 mm$$ is split into 8 identical droplets. Find the increase in surface energy. (Surface tension of mercury is $$0.465{ J/m }^{ 2 }$$)
  • $$23.4\mu J$$
  • $$18.5\mu J$$
  • $$26.8\mu J$$
  • $$16.8\mu J$$
Water does not wet an oily glass, because
  • cohesive force of oil $$>>$$ adhesive force between oil and glass
  • cohesive force of oil $$>$$ cohesive force of water
  • oil repels water
  • cohesive force of water $$>$$ adhesive force between water and oil molecules
No capillarity will take place if:-
(i) The liquid is at its boiling point
(ii) The liquid is at its freezing point
(iii) The angle of contact is $$0^{\circ}$$
(iv) The angle of contact is $$90^{\circ}$$
  • (i,ii)
  • (i,iv)
  • (i,ii,iii)
  • (ii,iv)
When the temperature is increased the angle of contact of a liquid
  • increases
  • decreases
  • remains the same
  • first increases and then decreases
Nature of meniscus for liquid of $$0^{0}$$ angle of contact
  • plane
  • parabolic
  • semi-spherical
  • cylindrical
A student uses a measuring cylinder to measure the volume of some water. The diagram shows
part of the measuring cylinder. The top and bottom of the meniscus are labelled.
What is the volume of the water?

1646905_cade8ee681da4b3a9c95947a45a098fd.png
  • $$47.0\ cm^{3}$$
  • $$47.5\ cm^{3}$$
  • $$49.0\ cm^{3}$$
  • $$49.5\ cm^{3}$$
In order to float a ring of area $$0.04 m^{2}$$ in a liquid of surface tension $$75 N/m$$, the required surface energy will be
  • $$3J$$
  • $$6.5J$$
  • $$1.5J$$
  • $$4J$$
The pressure at the bottom of a tank containing a liquid does not depend on
  • acceleration due to gravity
  • height of the liquid column
  • area of the bottom surface
  • nature of the liquid
A capillary tube, made of glass is dipped into mercury. Then:
  • mercury rises in the capillary tube.
  • mercury descends in capillary tube.
  • mercury rises and flows out of capillary tube.
  • mercury neither rises nor descends in the capillary tube.
A capillary tube is dipped in water vertically.Water rises to a height of 10mm. The tube is now tilted and makes an angle 60$$^{o}$$ with vertical.Now water rises to a height of:
  • 10 mm
  • 5 mm
  • 20 mm
  • 40 mm
The liquid meniscus in a capillary tube will be convex, if the angle of contact is :
  • greater than $$90^{o}$$
  • less than $$90^{o}$$
  • equal to $$90^{o}$$
  • equal to zero
A capillary tube when immersed vertically in a liquid rises to 3 cm. If the tube is held immersed in the liquid at an angle of 60$$^{o}$$ with the vertical,the length of the liquid column along the tube will be:
  • 2 cm
  • 4.5 cm
  • 6 cm
  • 7.5 cm
A vessel whose bottom has round holes with diameter of $$1mm $$ is filled with water. Assuming that surface tension acts only at holes, then the maximum height to which the water can be filled in vessel without leakage is
(Given surface tension of water is $$75 \times 10 ^{-3} N/m$$ and $$g =10m / s^{2}$$)
  • $$3 cm$$
  • $$0.3 cm$$
  • $$3 mm$$
  • $$3 m$$
Three tubes A, B, C are connected to a horizontal pipe in which liquid is flowing. The radii of the pipes at the joints of A, B and C are 2 cm, 1 cm and 2 cm respectively. The height of the liquid:
23597_3e15910953f946709ac68c6775094c57.png
  • in A is maximum
  • in A and C is equal
  • is same in all the three
  • in A and B is same
A water barrel having water up to depth '$$d$$' is placed on a table of height '$$h$$'. A small hole is made on the wall of the barrel at its bottom. If the stream of water coming out of the hole falls on the ground at a horizontal distance '$$R$$' from the barrel, then the value of '$$d$$' is:
  • $$\dfrac{4h}{R^{2}}$$
  • $$4hR^{2}$$
  • $$\dfrac{R^{2}}{4h}$$
  • $$\dfrac{h}{4R^{2}}$$
Match List I with List - II
List - IList - II
a) Meniscus of water in a glass Capillary tube
e) convex
b) Meniscus of water in silver capillary tubef) do not over flow
c) Meniscus of mercury in glass capillary tubeg) flat
d) Water in glass capillary tube of insufficient lengthh) concave
The correct match is :
  • a -- h; b-- g; c-- e; d-- f
  • a -- e; b-- f;c-- g; d -- h
  • a -- f; b-- e; c--g; d-- h
  • a-- h; b-- g; c-- f; d-- e
Four identical capillary tubes $$a, b, c$$ and $$d$$ are dipped in four beakers containing water with tube ‘$$a$$’ vertically, tube ‘$$b$$’ at $$30^{o}$$, tube ‘$$c$$’ at $$45^{o}$$ and tube ‘$$d$$’ at $$60^{o}$$ inclination with the vertical. Arrange the lengths of water column in the tubes in descending order.
  • $$d, c, b, a$$
  • $$d, a, b, c$$
  • $$a, c, d, b$$
  • $$a, b, c, d$$
Rain drops fall with terminal velocity due to:
  • Buoyancy
  • Viscosity
  • Low weight
  • surface tension
The velocity of the wind over the surface of the wing of an aeroplane is 80 ms$$^{-1}$$ and under the wing 60 ms$$^{-1}$$. If the area of the wing is 4m$$^{2}$$, the dynamic lift experienced by the wing is [ density of air $$=$$ 1.3 kg. m$$^{-3}$$]:
  • 3640 N
  • 7280 N
  • 14560 N
  • 72800 N
A solid rubber ball of density 'd' and radius 'R' falls vertically through air. Assume that the air resistance acting on the ball is F $$=$$ KRV where K is constant and V is its velocity. Because of this air resistance the ball attains a constant velocity called terminal velocity $$V_{T}$$ after some time.Then $$V_{T}$$ is:
  • $$\dfrac{4\pi R^{2}dg}{3K}$$
  • $$\dfrac{3K}{4\pi R^{2}dg}$$
  • $$\dfrac{4}{3}\dfrac{\pi r^{3}dg}{K}$$
  • $$\pi rdgk$$
Assertion: A raindrop after falling through some height attains a constant velocity

Reason: At constant velocity, the viscous drag is equal to its weight.
  • Both assertion and reason are true and reason is correct explanation of assertion.
  • Both assertion and reason are true but reason is not the correct explanation of assertion.
  • Assertion is true but reason is false.
  • Both assertion and reason are false.
A drop of water of radius r is falling through the air of coefficient of viscosity $$\eta $$ with a constant velocity of v. The resultant force on the drop is:
  • $$\dfrac{1}{6\pi \eta rv }$$
  • $$6\pi \eta rv $$
  • $$\sqrt{6\pi \eta rv }$$
  • zero
Read the following statements and pick the correct choice
Statement A: With increase in temperature, viscosity of a gas increases and that of a liquid decreases.
Statement B: If the density of a small sphere is equal to the density of the liquid in which it is dropped, then the terminal velocity of the sphere will be zero.
  • Both A and B are true
  • Both A and B are false
  • A is true and B is false
  • B is true but A is false.
A small ball is dropped in a viscous liquid. Its fall in the liquid is best described by the figure:
23645_30eca573766d4dff8f4dea106d19b53e.png
  • Curve A
  • Curve B
  • Curve C
  • Curve D
After terminal velocity is reached the acceleration of a body falling through a viscous fluid is :
  • zero
  • g
  • less than g
  • greater than g
Section-ASection-B
a) Incompressible liquide) Density constant
b) Turbulent flowf) Stream lines
c) Tube of flowg) Constant
d) Fluid flux rate in laminar flowh) Reynold's no $$> 2000$$
  • a-f; b-e; c-g; d-h
  • a-e; b-h; c-f; d-g
  • a-g; b-f; c-e; d-h
  • a-h; b-g; c-e; d-f
When a metallic sphere is dropped in a long column of a liquid, the motion of the sphere is opposed by the viscous force of the liquid. If the apparent weight of the sphere equals to the retarding forces on it, the sphere moves down with a velocity called:
  • critical velocity
  • terminal velocity
  • velocity gradient
  • constant velocity
A ball is dropped into coaltar. Its velocity-time curve will be
The reading of a pressure meter attached with a closed water pipe is 3.5 x 10$$^{5}$$ N m$$^{-2}$$. On opening the valve of the pipe, the reading of pressure meter is reduced to 3 x 10$$^{5}$$ N m$$^{-2}$$. Calculate the speed of water flowing in the pipe.
  • $$10 cm/s$$
  • $$10 m/s$$
  • $$0.1 m/s$$
  • $$0.1 cm/s$$
The initial speed with which water strikes the ground in $$ms^{-1}$$ is:
  • $$10$$
  • $$5$$
  • $$5\sqrt{2}$$
  • $$10\sqrt{2}$$
There is a hole at the side-bottom of a big water tank. The area of the hole is $$2\ mm^{2}$$. Through it, a pipe is connected. The upper surface of the water is $$5\ m$$ above the hole. The rate of flow of water through the pipe is ( in $$m^{3}s^{-1}$$) ( $$g= 10 \ ms^{-2}$$)
  • $$4 \times 10^{-5}$$
  • $$4 \times 10^{5}$$
  • $$4 \times 10^{-6}$$
  • $$28 \times 10^{-6}$$
At what speed will the velocity head of stream of water be equal to 40cm?
  • 280 ms$$^{-1}$$
  • 2.80 cm/s
  • 280 cms$$^{-1}$$
  • 0.280 m/s
The level of water in a tank is 5m high. A hole of area of cross section 1 cm$$^{2}$$ is made at the bottom of the tank. The rate of leakage of water from the hole in $$m^{3}s^{-1}$$ is ( g $$=$$ 10ms$$^{-2}$$):
  • $$10^{-3}$$
  • $$10^{-4}$$
  • $$10$$
  • $$10^{-2}$$
Calculate the velocity of efflux of kerosene oil from an orifice of a tank in which pressure is $$4 atm$$. The density of kerosene oil $$= 720 kg m^{-3}$$ and $$1$$ atmospheric pressure $$= 1.013 \times 10^{5}N m^{-2}$$.
  • $$3.355 m/s$$
  • $$33.55 m/s$$
  • $$335.5 m/s$$
  • $$33.55 cm/s$$
In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the upper and lower surfaces of the wing are $$70m s^{-1}$$ and $$63 ms^{-1}$$ respectively. What is the lift on the wing, if its area is $$2.5 m^{2}$$ ? Take the density of air to be $$1.3kg m^{-3}$$.
  • $$1513 N$$
  • $$1513\ dynes$$
  • $$151.3 N$$
  • $$151.3\ dynes$$
 The initial speed with which water flows out from the orifice in ms$$^{-1}$$ is (g $$=$$ 10ms$$^{-2}$$):
  • 10
  • 5
  • 5.$$\sqrt{2}$$
  • 10.$$\sqrt{2}$$
In a horizontal pipe line of uniform cross-section,pressure falls by $$5\ Pa$$ between two points separated by $$1\ km$$. The change in the kinetic energy per kg of the oil flowing at these points is :(Density of oil $$= 800\ kgm^{-3}$$)
  • $$6.25 \times 10^{-3}\ Jkg^{-1}$$
  • $$5.25 \times 10^{-4}\ Jkg^{-1}$$
  • $$3.25 \times 10^{-5}\ Jkg^{-1}$$
  • $$4.25 \times 10^{-2}\ Jkg^{-1}$$
A horizontal pipe of non uniform cross section has water flow through it such that the velocity is $$2ms^{-1}$$ at a point where the pressure is $$40 kPa$$. The pressure at a point where the velocity of water flow is $$3 ms^{-1}$$ is : ( in $$kPa$$)
  • $$27$$
  • $$60$$
  • $$37.5$$
  • $$40$$
In a horizontal oil pipe line of constant cross sectional area the decrease of pressure between two points 100 km apart is 1500 pa. The loss of energy per unit volume per unit distance is ----Joule.
  • 15
  • 0.015
  • 0.03
  • zero
A room has a window of area $$A$$. Out side of the room wind is blowing parallel to the window with a velocity $$v$$. If the density of air is $$\rho $$ , then the force acting on the window is:
  • $$\dfrac{1}{2}\dfrac{\rho v^{2}}{A}$$
  • $$\dfrac{1}{2}\rho v^{2}A$$
  • $$\rho v^{2}A$$
  • $$2\rho v^{2}A$$
Water is maintained at a height of 10m in a tank.The diameter of a circular aperture needed at the base of the tank to discharge water at the rate of 26.4m$$^{3}$$ min$$^{-1}$$ is(Given that g $$=$$ 9.8 m s$$^{-2})$$:
  • 0.2 cm
  • 2 m
  • 0.2 m
  • 2 cm
An aeroplane of mass $$6000 \ kg$$ is flying at an altitude of $$3 \ km$$. If the area of the wings is $$30 \ m^{2}$$ and the pressure at the lower surface of wings is $$0.6\times10^{5}\ pa$$, the pressure on the upper surface of wings is : ( in pascal) ( $$g= 10 \ ms^{-2}$$)
  • $$5.8 \times 10^{4}$$
  • $$6.8 \times 10^{4}$$
  • $$7.8 \times 10^{4}$$
  • $$8.8 \times 10^{4}$$
The pressure at the top of a building of height $$200m$$ is $$500kPa$$. The minimum pressure required at the base of the building to pump water to a closed tank on the top of the building is($$g=10m/s^{2}$$)
  • $$2.5 \times 10^{4}Pa$$
  • $$2.5 \times 10^{5}Pa$$
  • $$2.5 \times 10^{6} Pa$$
  • $$2.5 \times 10^{3} Pa$$
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Practice Class 11 Engineering Physics Quiz Questions and Answers