JEE Physics Mechanical Properties Of Fluids MCQs Set C

Question: The neck and bottom of a bottle are 3 cm and 15 cm in radius respectively. If the cork is pressed with a force 12 N in the neck of the bottle, then force exerted on the bottom of the bottle is

• a) 300 N
• b) 600 N
• c) 150 N
• d) 30 N

Answer: 300 N

Question:

• a) 0.8 gcc^–1
• b) 1.2 gcc^–1
• c) 1.4 gcc^–1
• d) 1.6 gcc^–1

Answer: 0.8 gcc^–1

Question: A wooden ball of density D is immersed in water of density d to a depth h below the surface of water and then released. Upto what height will the ball jump out of water?

• a)

  

• b)

  

• c) h
• d) Zero

Answer:

Question: A piece of solid weighs 120 g in air, 80 g in water and 60 g in a liquid. The relative density of the solid and that of the liquid are respectively

• a)

  

• b)

  

• c)

  

• d) 3, 2

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Ice pieces are floating in a beaker A containing water and also in a beaker B containing miscible liquid of specific gravity 1.2. When ice melts, the level of

• a) Liquid in B increases
• b) Water decreases in A
• c) Water increases in A
• d) Liquid in B decreases

Answer: Liquid in B increases

Question: A vessel contains oil (density 0.8 g cm^–3) over mercury (density 13.6 g cm^–3). A homogenous sphere floats with half volume immersed in mercury and the other half in oil. The density of the material of the sphere in gcm^–3 is

• a) 7.2
• b) 6.4
• c) 3.3
• d) 12.8

Answer: 7.2

Question: Two solid pieces, one of steel and the other of aluminium when immersed completely in water have equal weights. When the solid pieces are weighed in air

• a) Aluminium piece will weigh more
• b) Steel peice will weigh more
• c) The weight of aluminium is half the weight of steel
• d) They have the same weight

Answer: Aluminium piece will weigh more

Question: A piece of wood is floating in water. When the temperature of water rises, the apparent weight of the wood will

• a) May increase or decrease
• b) Increase
• c) Decrease
• d) Remain same

Answer: May increase or decrease

Question:

• a) Both l and h decrease
• b) l increases and h decreases
• c) l decreases and h increases
• d) Both l and h increase

Answer: Both l and h decrease

More Questions........................................

Question: An iceberg is floating in water. The density of ice in the iceberg is 917 kg m^–3 and the density of water is 1024 kg m^–3. What percentage fraction of the iceberg would be visible?

• a) 10%
• b) 5%
• c) 12%
• d) 8%

Answer: 10%

Question:  A piece of wax wieghs 18.03 g in air. A piece of metal is found to weigh 17.3 g in water. It is tied to the wax and both together weigh 15.23 g in water. Then, the specific gravity of wax is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Eight equal drops of water are falling through air with a steady velocity of 10 cm^–1. If the drops combine to form a single drop big in size, then the terminal velocity of this big drop is

• a) 40 cms^–1
• b) 10 cms^–1
• c) 30 cms^–1
• d) 80 cms^–1

Answer: 40 cms^–1

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Streamline flow is more likely for liquid with

• a) Low density and high viscosity
• b) Low density and low viscosity
• c) High density and high viscosity
• d) High density and low viscosity

Answer: Low density and high viscosity

Question: An air bubble of radius 10^–2 m is rising up at a steady rate of 2 × 10^–3 ms^–1 through a liquid of density 1.5 × 10³ kg m^–3, the coefficient of viscosity neglecting the density of air, will be (g = 10 ms^–2)

• a) 167 units
• b) 334 units
• c) 83.5 units
• d) 23.2 units

Answer: 167 units

Question: The flow of liquid is laminar or streamline is determined by

• a) Rate of flow of liquid
• b) Density of fluid
• c) Coefficient of viscosity of liquid
• d) None of these

Answer: Rate of flow of liquid

Question: A boat carrying a number of large stones is floating in a water tank. What would happen to the water level, if a few stones are unloaded into water?

• a) Falls
• b) Rises
• c) Remains unchanged
• d) Rises till half the number of stones are unloaded and then begins to fall

Answer: Falls

Question:  The velocity of a small ball of mass M and density d₁ when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is d₂, the viscous force acting on the ball is

• a)

  

• b)

  

• c)

  

• d) mgd₁d₂

Answer:

Question: There are two holes one each along the opposite sides of a wide rectangular tank. The cross-section of each hole is 0.01 m² and the vertical distance between the holes is one metre. The tank is filled with water. The net force on the tank in newton when the water flows out of the holes is (density of water = 1000 kgm^–3)

• a) 200
• b) 300
• c) 400
• d) 100

Answer: 200

Question:  A hole is made at the bottom of the tank filled with water (density 1000 kg/m³). If the total pressure at the bottom of the tank is 3 atm (1 atm = 10⁵ N/m²), then the velocity of efflux is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: horizontal pipe line carries water in stremline flow. At a point where the cross-sectional area is 10 cm² the water velocity is 1 ms^–1 and pressure is 2000 Pa. The pressure of water at another point where the crosssectional area is 5 cm², is

• a) 500 Pa
• b) 800 Pa
• c) 400 Pa
• d) 200 Pa

Answer: 500 Pa

Question: A rectangular vessel when full of water, takes 10 min to be emptied through an orifice in its bottom. How much time will it take to be emptied when half filled with water?

• a) 7 min
• b) 5 min
• c) 3 min
• d) 9 min

Answer: 7 min

Question: A metal plate of area 10³ cm² rests on a layer of oil 6 mm thick. A tangential force 10^–2 N is applied on it to move it with a constant velocity of 6 cms^–1. The coefficient of viscosity of the liquid is

• a) 0.1 poise
• b) 0.5 poise
• c) 0.7 poise
• d) 0.9 poise

Answer: 0.1 poise

Question: With an increase in temperature, surface tension of liquid (except molten copper and cadmium)

• a) Decreases
• b) Increases
• c) Remain same
• d) First decreases then increases

Answer: Decreases

Question:

• a)

  

• b) 2.46 mJ
• c) 8 mJ
• d) None of these

Answer: 

Question: A mercury drop of radius 1.0 cm is sprayed into 10⁶ droplets of equal sizes. The energy expended in this process is (surface tension of mercury is equal to 32 × 10^–2 Nm^–1)

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 0.11 Nm^–1
• b) 0.7 Nm^–1
• c) 0.072 Nm^–1
• d) None of these

Answer: 0.11 Nm^–1

Question: A liquid does not wet the sides of a solid, if the angle of contact is

• a) Obtuse
• b) 90°
• c) Acute
• d) Zero

Answer: Obtuse

Question: Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to a smaller one?

• a) 2^2/3 : 1
• b) 1 : 1
• c) 2^1/2 : 1
• d) None of these

Answer: 2^2/3 : 1

Question: The term ‘fluid’ is used for

• a) Both liquids and gases
• b) Gases only
• c) Liquids only
• d) A mixture of liquid and gas only

Answer: Both liquids and gases

Question: Select wrong statement about pressure

• a) None of these
• b) Pressure is always compressive in nature
• c) Pressure is a scalar quantity
• d) Pressure at a point is same in all directions

Answer: None of these

Question: Gauge pressure

• a) All of these
• b) May be zero
• c) May be negative
• d) May be positive

Answer: All of these

Question: Figure shows two containers P and Q with same base area A and each filled upto same height with same liquid. Select the correct alternative

• a) p_x = p_y
• b) p_x > p_y
• c) p_y > p_x
• d) None of these

Answer: p_x = p_y

Question: The pressure of confined air is p. If the atmospheric pressure is P, then

• a) P is less than p
• b) P is equal to p
• c) P is greater than p
• d) P may be less or greater than p depending on the mass of the confined air

Answer: P is less than p

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 10
• b) 15
• c) 20
• d) 25

Answer: 10

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  A barometer kept in an elevator reads 76 cm when it is at rest. If the elevator goes up with some acceleration, the reading will be

• a) < 76 cm
• b) Zero
• c) > 76 cm
• d) 76 cm

Answer: < 76 cm

Question:

• a) 0.8 N
• b) 1 N
• c) 8 N
• d) 16 N

Answer:  0.8 N