Calculate the work done in blowing up a soap bubble from an initial surface area of 0 . 5 × 10 - 4 m 2 to final surface area of 1 . 1 × 10 - 4 m 2 . The surface tension of soap solution is 0 . 03 Nm - 1 .

Given, Initial surface area of bubble = 0 . 5 c m 2 = A 1 Final surface area of soap bubble = 1 . 1 c m 2 = A 2 Surface tension of soap solution = 3 × 10 - 1 N / m = S Increase in surface area of soap bubble = 2 1 . 1 - 0 . 5 = 1 . 2 c m 2 = 0 . 00012 m 2 Work done = S × i n c r e a s e i n s u r f a c e a r e a = 3 × 10 - 1 × 0 . 00012 = 36 × 10 - 6 N / m We know that 1 N / m = 1 J Work Done = 36 × 10 - 6 J

EASY

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IMPORTANT

Earn 100

A bubble of steam $1 mm$ in diameter is formed at a depth of $10 cm$ below the surface of water in a beaker. If the barometric pressure is $75.10 cm$ of mercury, what is the pressure of water vapour inside the bubble. Take density of water $= 0.96 gm {cc}^{- 1}$ , surface tension of water $= 60$ dyne $/ cm$ .

Important Questions on Fluid Statics

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 41

A cylindrical vessel of radius

10 cm

has a small hole in its base. The edges of the hole are waxed, leaving a circular aperture of radius

0.2 mm

. To what depth can the vessel be sunk in water before water enters into the vessel (

S . T

. of water

= 72

dyne

{cm}^{- 1}

]

EASY

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IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 42

Turpentine has a density of

0.87 gm {cm}^{- 3}

. Its angle of contact with glass is

17 °

. It rises

2.0 cm

in a glass tube of diameter

0.60 mm

. What is its surface tension?

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 43

A cylindrical can of radius

10 cm

and weighing

500 gm

has a small hole of radius

0.2 mm

in its base. If floated in water how much extra weight will it be able to carry before the water enters ?

S . T

. of water

= 73

dyne

{cm}^{- 1}

EASY

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IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 44

Water rises up in a glass capillary up to a height of

9 cm

, while mercury falls down by

3.4 cm

in same capillary tube. If angle of contact for water-glass and mercury glass

0 °

and

135 °

respectively, calculate the ratio of surface tension of mercury and water.

EASY

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IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 45

Two equal spherical bubble of radius

a

each coalesces to form a spherical bubble of radius

b

. If

P

is the atmospheric pressure, show that the surface tension of the bubble is

\frac{P (2 a^{3} - b^{3})}{4 (b^{2} - 2 a^{2})}

EASY

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IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 46

\cup

-tube is such that the diameter of one limb is

0.4 mm

and that of the other is

0.8 mm

. When water is poured into it, it is found that the difference of water levels in the two limbs is

3.57 cm

. If the angle of contact is assumed to be zero, calculate the surface tension of water.

MEDIUM

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IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 47

\cup

-shaped wire is dipped in soap solution and removed. The thin soap film formed between the wire and a light slider supports a total weight of

1.5 \times 10^{- 2} N

. The length of slider is

0.30 m

. Claculate the surface tension of the film.

MEDIUM

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 13 - Fluid Statics>EXERCISE>Q 48

Calculate the work done in blowing up a soap bubble from an initial surface area of

0.5 \times 10^{- 4} m^{2}

to final surface area of

1.1 \times 10^{- 4} m^{2}

. The surface tension of soap solution is

0.03 {Nm}^{- 1}

A bubble of steam 1 mm in diameter is formed at a depth of 10 cm below the surface of water in a beaker. If the barometric pressure is 75.10 cm of mercury, what is the pressure of water vapour inside the bubble. Take density of water =0.96 gm cc-1, surface tension of water =60 dyne/cm.

Important Questions on Fluid Statics

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