NEET Physics Pressure Density Pascals Law and Archimedes Principle MCQs Set 01

Question. Hydraulic lifts and hydraulic brakes are based on
(a) Pascal's law
(b) Bernoulli's principle
(c) Archimedes' principle
(d) Stoke's law

Answer: A

Question. According to archimedes' principle, loss of weight of a body immersed in a liquid is equal to
(a) weight of the liquid displaced
(b) weight of the total liquid
(c) weight of the body
(d) None of these

Answer: A

Question.  _________ and _________ play the same role in case of fluids as force and mass play in case of solids.
(a) Pressure and density
(b) Thrust and volume
(c) Thrust and density
(d) Pressure and thrust

Answer: A

Question. Pressure applied to enclosed fluid is
(a) transmitted unchanged to every portion of the fluid and wall of containing vessel
(b) increased in proportion to the mass of the fluid and then transmitted
(c) diminished and transmitted to wall of container
(d) increased and applied to every part of the fluid

Answer: A

Question. The pressure at the bottom of a tank containing a liquid does not depend on
(a) area of the bottom surface
(b) nature of the liquid
(c) height of the liquid column
(d) acceleration due to gravity

Answer: A

Question. Specific gravity of a body is numerically equal to
(a) density of body in water
(b) relative density of the body
(c) weight of the body in water
(d) weight of the body in air

Answer: A

Question. Assertion: A small iron needle sinks in water while a large iron ship floats.
Reason: The shape of iron needle is like a flat surface while the shape of a ship is that which makes it easier to float.
(a) Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Consider an iceberg floating in sea water. The density of sea water is 1.03 g/cc and that of ice is 0.92 g/cc. The fraction of total volume of iceberg above the level of sea water is near by
(a) 11%
(b) 8%
(c) 3%
(d) 1.8%

Answer: A

Question. A block of ice floats on a liquid of density 1.2 in a beaker then level of liquid when ice completely melt
(a) rises
(b) remains same
(c) lowers
(d) None of these

Answer: A

Question. A vessel contains oil (density = 0.8 gm/cm³) over mercury (density = 13.6 gm/cm³). A homogeneous sphere floats with half of its volume immersed in mercury and the other half in oil. The density of the material of the sphere in gm/cm³ is
(a) 7.2
(b) 12.8
(c) 6.4
(d) 3.3

Answer: A

Question. In a hydraulic lift, compressed air exerts a force F₁ on a small piston having a radius of 5 cm. This pressure is transmitted to a second piston of radius 15 cm. If the mass of the load to be lifted is 1350 kg, find the value of F₁ ? The pressure necessary to accomplish this task is
(a) 1.9 × 10⁵ Pa
(b) 1.4 × 10⁵ Pa
(c) 2 × 10⁵ Pa
(d) None of these

Answer: A

Question. Assertion: The apparent weight of a floating body is zero.
Reason: The weight of the block acting vertically downwards is balanced by the buoyant force acting on the block upwards.
(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. The force acting on a window of area 50 cm × 50 cm of a submarine at a depth of 2000 m in an ocean, interior of which is maintained at sea level atmospheric pressure is (Density of sea water = 10³ kgm^–3, g = 10 ms^–2)
(a) 5 × 10⁶ N
(b) 5 × 10⁵ N
(c) 10⁶ N
(d) 25 × 10⁶ N

Answer: A

Question. A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The specific gravities of concrete and sawdust are respectively 2.4 and 0.3 for this sphere to float with its entire volume submerged under water. Ratio of mass of concrete to mass of sawdust will be
(a) 4
(b) 3
(c) zero
(d) 8

Answer: A

Question.  The two thigh bones, each of cross-sectional area 10 cm² support the upper part of a human body of mass 40 kg. Estimate the average pressure sustained by the bones. Take g = 10 m/s²
(a) 2 × 10⁵ N/m²
(b) 2 × 10⁷ N/m²
(c) 5 × 10⁴ N/m²
(d) 3 × 10⁶ N/m²

Answer: A

Question.  A boy can reduce the pressure in his lungs to 750 mm ofmercury. Using a straw he can drink water from a glass upto the maximum depth of (atmospheric pressure = 760 mm of mercury; density of mercury = 13.6 gcm^–3)
(a) 13.6 cm
(b) 9.8 cm
(c) 76 cm
(d) 10 cm

Answer: A

Question. Assertion : Imagine holding two identical bricks under water. Brick A is completely submerged just below the surface of water, while Brick B is at a greater depth. The magnitude of force exerted by the person (on the brick) to hold brick B in place is the same as magnitude of force exerted by the person (on the brick) to hold brick A in place.
Reason : The magnitude of buoyant force on a brick completely submerged in water is equal to magnitude of weight of water it displaces and does not depend on depth of brick in water.
(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