EASY
Earn 100

Statement (A): When the temperature increases the viscosity of gases increases and the viscosity of liquids decreases.

Statement (B): Water does not wet an oily glass because cohesive force of oil is less than that of water.

Statement (C) : A liquid will wet a surface of a solid if the angle of contact is greater than 90°.

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Important Questions on Mechanical Properties of Matter

EASY
Identify the incorrect statement regarding Reynold's number Re:
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:
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.
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)
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
Under a constant pressure head, the rate of flow of orderly volume flow of liquid through a capillary tube is V. if the length of the capillary is doubled and the diameter of the bore is halved, the rate of flow would become
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
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
EASY
The speed of the water in a river is V near the surface. If the coefficient of viscosity of water is η and the depth of the river is H, then the shearing stress between the horizontal layers of water 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
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:
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.
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
A force that is caused due to attraction of particles in the layer of fluid bulk is called?
HARD
Which of the following statements is true in the context of inertial force?
EASY
How does pressure affect viscosity?
 
EASY

What are the various factors affecting the viscosity of a liquid explain?
 

MEDIUM
When the temperature increases, the viscosity of
HARD
What is the inertial force in fluids?