HARD
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A metal plate of area 103 cm2 rests on a layer of oil  6 mm thick. A tangential force of 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

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Important Questions on Fluid Dynamics

EASY
The velocity of upper layer of water in a river is 36 km h-1. Shearing stress between horizontal layers of water is 10-3 N m-2. Depth of the river is _____ m. (Co-efficient of viscosity of water is 10-2 Pa s)
EASY

A flat plate of area 10 cm2 is separated form a large plate by a layer of Glycerine 1 mm thick. If the coefficient of viscosity of Glycerine is 20 poise, the force required to keep the plate moving with a velocity of 1 cm s-1 is       
 

EASY
If p is the density and η is coefficient of viscosity of fluid which flows with a speed v in the pipe of diameter d, the correct formula for Reynolds number Re is
MEDIUM
Two capillary tubes of same length each of 50 cm but of different radii 4 mm and 2 mm are connected in series. When water flows, the pressure difference between the ends of the arrangement is P. Then the pressure difference between the ends of the first tube is
MEDIUM
A solid sphere of volume V experiences a viscous force F when descending with a speed v in a liquid. If another solid sphere of volume 27 V descends with the same speed v in the same liquid, it experiences a viscous force
HARD
Consider a thin square plate floating on a viscous liquid in a large tank. The height h of the liquid in the tank is much less than the width of the tank. The floating plate is pulled horizontally with a constant velocity u0. Which of the following statements is (are) true?
EASY
Oil is used for frying food materials rather than water, since oil
HARD
A graph of vapour pressure and temperature for three different liquids X,Y and Z is shown below:
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The following inferences are made:
AX has higher intermolecular interactions compared to Y.
BX has lower intermolecular interactions compared to Y.
CZ has lower intermolecular interactions compared to Y.
The correct inferences is/are:
HARD

A steel ball is dropped in a viscous liquid. The distance of the steel ball from the top of the liquid is shown below. The terminal velocity of the ball is closest to

 

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MEDIUM
The velocity of a small ball of mass M and density ρ, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is ρ2, then the viscous force acting on the ball will be:
EASY
The relative viscosity of blood remains constant between
EASY
The velocity of water in a river is 18 km h-1 near the surface. If the river is 5 m deep, find the shearing stress between the horizontal layers of water. The coefficient of viscosity of water=10-2 poise.
EASY

A metal block of base area 0.20 m2 is placed on a table, as shown in figure. A liquid film of thickness 0.25 mm is inserted between the block and the table. The block is pushed by a horizontal force of 0.1 N and moves with a constant speed. If the viscosity of the liquid is 5.0×103 Pl, the speed of block is ______ ×10-3 m s-1.

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MEDIUM
The velocity of water in a river is 18 km h-1 near the surface. If the river is 5m deep, find the shearing stress between the horizontal layers of water. The coefficient of viscosity of water=10-2 poise.
MEDIUM
The qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solutions of KCl, CH3OH  and CH3CH211OSO3- Na+ at room temperature. The correct assignment of the sketches is -

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MEDIUM
The units of surface tension and viscosity of a liquid, respectively, are
MEDIUM
A liquid does not wet the solid surface if angle of contact is:
EASY
Identify the incorrect statement regarding Reynold's number Re:
HARD
Water from a pipe is coming at a rate of 100 liters per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of: (density of water = 100 kg/m3, coefficient of viscosity of water =1 mPa s)
MEDIUM
If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter 2π cm then the Reynolds number for the flow is (density of water = 103  kg/m3 and viscosity of water=10-3 Pa.s ) close to: