NEET Physics Mechanical Properties of Fluid MCQs Set A

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
(d) None of these

Answer: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A