JEE Questions for Physics Mechanical Properties Of Fluids Quiz 10 - MCQExams.com

Two solid spheres of same metal but of mass M and 8 M full simultineously on a viscous liquid and their terminal velocity are V and 'nv' then value of 'n' is
  • 16
  • 8
  • 4
  • 2

Physics-Mechanical Properties of Fluids-78981.png

  • Physics-Mechanical Properties of Fluids-78982.png
  • 2)
    Physics-Mechanical Properties of Fluids-78983.png

  • Physics-Mechanical Properties of Fluids-78984.png

  • Physics-Mechanical Properties of Fluids-78985.png
Water is flowing continuously dram a temp having an internal diameter 8 × 103m . The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance 2 × 10-1m below the tap is close to

  • Physics-Mechanical Properties of Fluids-78987.png
  • 2)
    Physics-Mechanical Properties of Fluids-78988.png

  • Physics-Mechanical Properties of Fluids-78989.png

  • Physics-Mechanical Properties of Fluids-78990.png
A large open tank has two holes in the wall one is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth a y from the top. When the tank is completely filled with water the quantities of water following out per second from both the holes are the some then R is equal to
  • 2πL
  • 2)
    Physics-Mechanical Properties of Fluids-78992.png
  • L

  • Physics-Mechanical Properties of Fluids-78993.png
Assertion : The blood pressure in humans is greater at the feet than at the brain.
Reason : Pressure of liquid at any point is proportional to height density of liquid.
(a)If both assertion and reason are true and the reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) IF the assertion and reason are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
Assertion : A bubble comes from the bottom of a lake to the top.
Reason : Its radius increases.
(a)If both assertion and reason are true and the reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) IF the assertion and reason are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
The resistance of a resistance thermometer has values 2.71 and 3.70 ohm at 10oC and 100oC. The temprature at which the resistance is 3.26 ohm is
  • 40o C
  • 50o C
  • 60o C
  • 70o C
At what temperature the centigrade (Celsius) and Fahrenheit readings at the same.
  • – 400
  • +400C
  • 36.60
  • – 370 C
A vessel contains 110 g of water the heat capacity of the vessel is equal to 10 g of water The initial temprature of water in vessel is 10o C If 220 g of hot water at 70o C is poured in the vessel the Final temperature meglecting radiation loss will be
  • 70o C
  • 80o C
  • 60o C
  • 50o C
In a water fall the water falls from a height of 100 cm. If the entire K.E. of water is converted in to heat the rise in temperature of water will be
  • 0.23o C
  • 0.46o C
  • 2.3o C
  • 0.023o C
2 kg of Ice at -20o C is mixed with 5 kg of water at 20o C in an insulating vessel having a negligible heat capacity calculate the final mass of water remaining in the container. It is given that the specific heats of water and ice care 1 k cal/kg per oC and 0.5 K cal/kg 1oC while the latent heat of fusion of ice is 80 k coil/kg
  • 7 kg
  • 6 kg
  • 4 kg
  • 2 kg
The variation of density of water with temprature is represented by the

  • Physics-Mechanical Properties of Fluids-78997.png
  • 2)
    Physics-Mechanical Properties of Fluids-78998.png

  • Physics-Mechanical Properties of Fluids-78999.png

  • Physics-Mechanical Properties of Fluids-79000.png
Assertion : The melting point of the ice decreases with increases pressure
Reason : Ice contracts on melting
(a) If both asseration and reason are true and the reason is the correct explanation of the reason.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
Assertion : Fahrenheit is the smallest unit measuring temperature.
Reason : Fahrenheit was the first temperature scale used for measuring temperature.
(a) If both asseration and reason are true and the reason is the correct explanation of the reason.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
A film of water is formed between two straight parallel wires of length 10 cm each separated by 0.5 cm. If their separation is increased by 1 cm while still maintaining their parallelism, how much work will have to be done? (Surface tension of water = 7.2 × 10–2 N/m)
  • 7.22 × 10–6 J
  • 1.44 × 10–5 J
  • 2.88 × 10–5 J
  • 5.76 × 10–5 J
Assertion : Melting of solid causes no change in internal energy.
Reason :Latent heat is the heat required melt a unit mass of solid.
(a) If both asseration and reason are true and the reason is the correct explanation of the reason.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
  • e
Assertion : The molecules of 0o C ice and 0o C water will have same potential energy.
Reason : Potential energy depends only on temperature of the system.
(a) If both asseration and reason are true and the reason is the correct explanation of the reason.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
Assertion : A beaker is completely filled with water at 40 C. It will overflow both where heated or cooled.
Reason : There is expansion of water below and above 40 C.
(a) If both asseration and reason are true and the reason is the correct explanation of the reason.
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
  • a
  • b
  • c
  • d
When there is no external force, the shape of a liquid drop is determined by
  • Surface tension of the liquid
  • Density of liquid
  • Viscosity of liquid
  • Temperature of air only
A drop of oil is placed on the surface of water. Which of the following statement is correct?
  • It will remain on it as a sphere
  • It will spread as a thin layer
  • It will be partly as spherical droplets and partly as thin film
  • It will float as a distorted drop on the water surface
A thread is tied slightly loose to a wire frame as in figure and the frame is dipped into a soap solution and taken out. The frame is completely covered with the film. When the portion A punctured with a pin, the thread
Physics-Mechanical Properties of Fluids-79001.png
  • Becomes concave towards A
  • Becomes convex towards A
  • Remains in the initial position
  • Either (a) or (b) depending on the size of A w.r.t. B
Small droplets of a liquid are usually more spherical in shape than larger drops of the same liquid because
  • Force of surface tension is equal and opposite to the force of gravity
  • Force of surface tension predominates the force of gravity
  • Force of gravity predominates the force of surface tension
  • Force of gravity and force of surface tension act in the same direction and are equal
Cohesive force is experienced between
  • Magnetic substances
  • Molecules of different substances
  • Molecules of same substances
  • None of the above
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 for water > adhesive force between water and oil molecules
A thin liquid film formed between a U - shaped wire and a light slider supports a weight of 1.5 × 10–2 N (see figure). The length of the slider is 30 cm and its weight negligible. The surface tension of the liquid film is
Physics-Mechanical Properties of Fluids-79002.png
  • 0.0125 Nm–1
  • 0.1 Nm–1
  • 0.05 Nm–1
  • 0.025 Nm–1
In the glass capillary tube, the shape of the surface of the liquid depends upon
  • Only on the cohesive force of liquid molecules
  • Only on the adhesive force between the molecules of glass and liquid
  • Only on relative cohesive and adhesive force between the atoms
  • Neither on cohesive nor on adhesive force
The force required to separate two glass plates of area 10–2 m2 with a film of water 0.05 mm thick between them, is (Surface tension of water is 70 × 10–3 N/m)
  • 28 N
  • 14 N
  • 50 N
  • 38 N
The maximum force, in addition to the weight required to pull a wire of 5.0 cm long from the surface of water at temperature 20oC, is 728 dynes. The surface tension of water is
  • 7.28 N/cm
  • 7.28 dyne/cm
  • 72.8 dyne/cm
  • 7.28 × 102 dyne/cm
Surface tension may be defined as
  • The work done per unit area in increasing the surface area of a liquid under isothermal condition
  • The work done per unit area in increasing the surface area of a liquid under adiabatic condition
  • The work done per unit area in increasing the surface area of a liquid under both isothermal and adiabatic conditions
  • Free surface energy per unit volume
Surface tension of a liquid is found to be influenced by
  • It increases with the increase of temperature
  • Nature of the liquid in contact
  • Presence of soap that increases it
  • Its variation with the concentration of the liquid
Small liquid drops assume spherical shape because
  • Atmospheric pressure exerts a force on a liquid drop
  • Volume of a spherical drop is minimum
  • Gravitational force acts upon the drop
  • Liquid tends to have the minimum surface area due to surface tension
A thin metal disc of radius r floats on water surface and bends the surface downwards along the perimeter making an angle θ with vertical edge of the disc. If the disc displaces a weight of water W and surface tension of water is T, then the weight of metal disc is
  • 2πrT + W
  • 2πrT cos θ – W
  • 2πrT cos θ + W
  • W – 2πrT cos θ
A 10 cm long wire is placed horizontally on the surface of water and is gently pulled up with a force of 2 × 10–2 N to keep the wire in equilibrium. The surface tension, in Nm–1 of water is
  • 0.1
  • 0.2
  • 0.001
  • 0.002
A thin liquid film formed between a U - shaped wire and a light slider supports a weight of 1.5 × 102 N(See figure). The length of the slider is 30 cm and its weight negligible. The surface tension of the liquid film is
Physics-Mechanical Properties of Fluids-79008.png
  • 0.0125 Nm–1
  • 0.1 Nm–1
  • 0.05 Nm–1
  • 0.025 Nm–1
Energy needed in breaking a drop of radius R into n drops of radii r is given by
  • 4πT (nr2 – R2)
  • 2)
    Physics-Mechanical Properties of Fluids-79010.png
  • 4πT (R2 – nr2)
  • 4πT (nr2 + R2)
The potential energy of a molecule increases when it is brought to the surface from the interior of a liquid because
  • At the free liquid surface gravitational potential energy is more
  • Work has to be done to move a molecule to the surface against the repulsive component of the inter molecular forces
  • Work has to be done to move a molecule to the surface against the attraction from other molecules
  • The temperature of the liquid surface is always more than that of the interior of the liquid
Work done is splitting a drop of water of 1 mm radius into 106 droplets is (Surface tension of water = 72 × 10–3 J/m2)
  • 9.58 × 10–5 J
  • 8.95 × 10–5 J
  • 5.89 × 10–5 J
  • 5.98 × 10–6 J
The amount of work done in blowing a soap bubble such that its diameter increases from d to D is (T = Surface tension of the solution)
  • 4π (D2 – d2)T
  • 8π (D2 – d2)T
  • π (D2 – d2)T
  • 2π (D2 – d2)T
If work W is done in blowing a bubble of radius R from a soap solution, then the work done in blowing a bubble of radius 2R from the same solution is
  • W/2
  • 2W
  • 4W

  • Physics-Mechanical Properties of Fluids-79014.png
If two identical mercury drops are combined to form a single drop, then its temperature will
  • Decrease
  • Increase
  • Remain the same
  • None of these
The surface tension of a liquid at its boiling point
  • Becomes zero
  • Becomes infinity
  • Is equal to the value at room temperature
  • Is half to the value at the room temperature

Physics-Mechanical Properties of Fluids-79017.png
  • 75.36 × 10–4 J
  • 37.68 × 10–4 J
  • 150.72 × 10–4 J
  • 75.36 J
If σ be the surface tension, the work done in breaking a big drop of radius R in n drops of equal radius is
  • Rn2/3 σ
  • (n2/3 – 1 )Rσ
  • (n1/3 – 1)Rσ
  • 4πR2 (n1/3 – 1)σ
When 106 small drops coalesce to make a new larger drop then the drop
  • Density increases
  • Density decreases
  • Temperature increases
  • Temperature decreases
8000 identical water drops are combined to form a big drop. Then, the ratio of the final surface energy to the initial surface energy of all the drops together is
  • 1 : 10
  • 1 : 15
  • 1 : 20
  • 1 : 25
The relation between surface tension T, surface area A and surface energy E is given by

  • Physics-Mechanical Properties of Fluids-79020.png
  • T = EA

  • Physics-Mechanical Properties of Fluids-79021.png

  • Physics-Mechanical Properties of Fluids-79022.png
If a water drop is kept between two glass plates, then its shape is

  • Physics-Mechanical Properties of Fluids-79024.png
  • 2)
    Physics-Mechanical Properties of Fluids-79025.png

  • Physics-Mechanical Properties of Fluids-79026.png
  • None of these
The excess pressure in a bubble of radius R of a gas in a liquid of surface tension S is

  • Physics-Mechanical Properties of Fluids-79027.png
  • 2)
    Physics-Mechanical Properties of Fluids-79028.png

  • Physics-Mechanical Properties of Fluids-79029.png

  • Physics-Mechanical Properties of Fluids-79030.png
If two soap bubbles of different radii are in communication with each other then
  • Air flows from larger bubble into the smaller one
  • The size of the bubbles remains the same
  • Air flows from the smaller bubble into the large one and the larger bubble grows at the expense of the smaller one
  • The air flows from the larger
The excess pressure inside one soap bubble is three times that inside a second soap bubble, then the ratio of their surface areas is
  • 1 : 9
  • 1 : 3
  • 3 : 1
  • 1 : 27
0:0:1


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