NEET Physics Mechanical Properties of Fluid MCQs Set A

Question:

a)

b)

c)

d)

Answer:

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

a)

b)

c)

d)

Answer:

Question: Along a streamline

a) the velocity of all fluid particles crossing a given position is constant

b) the velocity of a fluid particle remains constant

c) the velocity of all the speed of a fluid particle remains constantfluid particles at a given instant is constant

Answer: the velocity of all fluid particles crossing a given position is constant

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) Both

d) None of these

Answer:  9 : 4

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) mercury

b) water

c) ethylalcohol

d) methyliodide

Answer: mercury

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

a)

b)

c)

d) energy is neither released nor absorbed

Answer:

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

d) more information is required

Answer: both the holes will fall at the same spot

Question:  An open glass tube is immersed in mercury in such a way that a length of 8 cm extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additional 46 cm. What will be length of the air column above mercury in the tube now?

(Atmospheric pressure = 76 cm of Hg)

a) 16 cm

b) 22 cm

c) 38 cm

d) 6 cm

Answer:  16 cm

Question: Two capillary tubes are of the same diameters. One is dipped in a liquid of relative density 0.8 while the other in a liquid of relative density 0.6. If surface tensions of these liquids are 60 and 50 milli N/m, respectively, and the angles of the contact are equal, compare the rise of liquids in the capillary tubes.

a) 9 : 10

b) 7 : 10

c) 3 : 10

d) 1 : 10

Answer: 9 : 10

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 thanm '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.

Answer: water rises upto the top of capillary tube and stays there without overflowing

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)

b)

c)

d)

Answer:

Question: The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 × 10^–11 Pa^–1 and density of water is 10³ kg/m³.What fractional compression of water will be obtained at the bottom of the ocean ?

a) 1.2 × 10^–2

b) 0.8 × 10^–2

c) 1.0 × 10^–2

d) 1.4 × 10^–2

Answer:  1.2 × 10^–2

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) 9.1 × 10^–4 m³

b) 8.9 × 10^–3 m³

c) 7.8 × 10^–3 m³

d) 8.7 × 10^–4 m³

Answer:  9.1 × 10^–4 m³

Question:

a)

b)

c)

d) None of these

Answer:

Question:  A glass capillary tube of internal radius r = 0.25 mm is immersed in water. The top end of the tube projected by 2 cm above the surface of the water. At what angle does the liquid meet the tube? Surface tension of water = 0.7 N/m.

a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:  A capillary tube of radius r is immersed vertically in a liquid such that liquid rises in it to height h (less than the length of the tube). Mass of liquid in the capillary tube is m. If radius of the capillary tube is increased by 50%, then mass of liquid that will rise in the tube, is

a)

b)

c)

d) m

Answer:

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) 928 kg m^–3

b) 650 kg m^–3

c) 800 kg m^–3

d) None of these

Answer: 928 kg m^–3

Question:   If two glass plates have water between them and are separated by very small distance (see figure), it is very difficult to pull them apart. It is because the water in between forms cylindrical surface on the side that gives rise to lower pressure in the water in comparison to atmosphere. If the radius of the cylindrical surface is R and surface tension of water is T then the pressure in water between the plates is lower by

a)

b)

c)

d)

Answer:

Question:  A glass capillary tube of internal radius r = 0.25 mm is immersed in water. The top end of the tube projected by 2 cm above the surface of the water. At what angle does the liquid meet the tube? Surface tension of water = 0.7 N/m.

a) 

b)

c)

d) None of these

Answer:

Question: Assertion: The pressure of water reduces when it flows from a narrow pipe to a wider pipe.
Reason: Since for wider pipe area is large, so flow of speed is small and pressure also reduces proportionately

a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.

b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion

c) Assertion is correct, reason is incorrect

d) Assertion is incorrect, reason is correct

Answer:  Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Question:  A mercury drop of radius 1 cm is sprayed into 10⁶ drops of equal size. The energy expressed in joule is (surface tension of Mercury is 460 × 10^–3 N/m)

a) 0.057

b) 5.7

c) 5.7 × 10^–4

d) 5.7 × 10^–6

Answer: 0.057

Question:  A capillary tube of radius R is immersed in water and water rises in it to a height H. Mass of water in the capillary tube is M. If the radius of the tube is doubled, mass of water that will rise in the capillary tube will now be

a) 2 M

b) M/2

c) 4 M

d) M

Answer:  2 M

Question:  A small sphere of radius ‘r’ falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to

a) r⁵

b) r⁴

c) r²

d) r³

Answer:  r⁵

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) zero

d) = H

Answer: > H

Question:  A vessel in the shape of a hollow hemisphere surmounted by a cone is held with the axis vertical and vertex uppermost. If it be filled with a liquid so as to submerge half the axis of the cone in the liquid, and the height of the cone be double the radius of its base, find the value of x, where the resultant downward thrust of the liquid on the vessel is x times the weight of the liquid that the hemisphere can hold.

a) 15/8

b) 1/8

c) 5/8

d) 15/2

Answer:  15/8

Question:  A rectangular gate shown should dip automatically when the water rises above a certain level. Determine that level in terms of h.

a) 1.732m

b) 1.512m

c) 1.212m

d) 2.123m

Answer: 1.732m

Question: A tank is filled with water upto a height H. Water is allowed to come out of a hole P in one of the walls at a depth h below the surface of water (see fig.) Express the horizontal distance X in terms H and h.

a)

b)

c)

d)

Answer:

Question:

a) 15 N

b) 22.5 N

c) 33.7 N

d) 45 N

Answer:  15 N

Question:   In a cylindrical water tank, there are two small holes A and B on the wall at a depth of h₁, from the surface of water and at a height of h₂ from the bottom of water tank. Surface of water is at height of h₂ from the bottom of water tank. Surface of water is at heigh H from the bottom of water tank. Water coming out from both holes strikes the ground at the same point S. Find the ratio of h₁ and h₂

a) Depends on H

b) 1 : 1

c) 2 : 2

d) 1 : 2

Answer: Depends on H

Question: A 0.7 kg solid cube having edge length 10 cm floats in water. How much volume of the cube is outside the water? [density of water = 1000 kg/m³]

a) 300 cm³

b) 400 cm³

c) 500 cm³

d) 600 cm³

Answer: 300 cm³

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:  A ring is cut from a platinum tube 8.5 cm internal and 8.7 cm external diameter. It is supported horizontally from the pan of a balance, so that it comes in contact with the water in a glass vessel. If an extra 3.97. If is required to pull it away from water, the  surface tension of water is

a) 72 dyne cm^–1

b) 63.35 dyne cm^–1

c) 70.80 dyne cm^–1

d) 60 dyne cm^–1

Answer:  72 dyne cm^–1

Question:

a)

b)

c)

d)

Answer:

Question:  A thin tube sealed at both ends is 100 cm long. It lies horizontally, the middle 20 cm containing mercury and two equal ends containing air at standard atmospheric pressure. If the tube is now turned to a vertical position, by what amount will the mercury be displaced ?

(Given : cross-section of the tube can be assumed to be uniform)

a) 5.18 cm

b) 8.65 cm

c) 0.0 cm

d) 2.95 cm

Answer:  5.18 cm

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d) None of these

Answer: