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 $90 °$ .

50% studentsanswered this correctly

Important Questions on Mechanical Properties of Matter

MEDIUM

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

\frac{ρ}{2}

, then the viscous force acting on the ball will be:

MEDIUM

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

R_{e}

HARD

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

Water from a pipe is coming at a rate of

100

liters per minute. If the radius of the pipe is

5 c m,

the Reynolds number for the flow is of the order of: (density of water =

100 k g / m^{3},

coefficient of viscosity of water

= 1 m P a s)

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

Identify the incorrect statement regarding Reynold's number

(R_{e}) :

HARD

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Question Image

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

A flat plate of area $10 {cm}^{2}$ 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

MEDIUM

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter

\frac{2}{\sqrt{π}} c m

then the Reynolds number for the flow is (density of water =

10^{3} k g / m^{3} a n d v i s c o s i t y o f w a t e r = 10^{- 3} P a . s

) close to:

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

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

u_{0}

. Which of the following statements is (are) true?

HARD

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

Two capillary of length L and 2L and of radii R and 2R are connected in series. The net rate of flow of fluid through them will be (given rate of the flow through single capillary, X =

\frac{π p R^{4}}{8 ɳ L}

)

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

In an unsteady flow the velocity at point in the flow varies with _________.

HARD

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

A metal plate of area

10^{3} {c m}^{2}

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 c m s}^{- 1}

. The coefficient of viscosity of the liquid is

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

Water in river 20 m deep is flowing at a speed of

10 {m s}^{- 1}

. The shearing stress between the horizontal layers of water in the river in

{N m}^{- 2}

is (coefficient of viscosity of water

= 10^{- 3}

SI units)

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

A liquid whose coefficient of viscosity is

η

flows on a horizontal surface. Let dx represent the vertical distance between two layers of liquid and dv represent the difference in the velocities of the two layers. Then the quantity

η (d ν / d x)

has the same dimensions as

EASY

Physics>Mechanics>Mechanical Properties of Matter>Viscosity

A solid ball of volume V is dropped in a viscous liquid. It experiences a viscous force F. If the solid ball of volume 2 V of same material is dropped in the same fluid then the viscous force acting on it will be _____.

Important Questions on Mechanical Properties of Matter

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