Surface Tension and Capillary Action

Interactive Feed

JEE Main 2014

On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius $R$ and making a circular contact of radius $r$ with the bottom of the vessel. If $r ≪ R$ and the surface tension of water is $T$ , value of $r$ just before bubbles detatch is (density of water is $ρ$ )

R^{2} \frac{ρ _{w} g}{3 T}

(B)

R^{2} \frac{ρ _{w} g}{6 T}

(C)

R^{2} \frac{ρ _{w} g}{T}

(D)

R^{2} \frac{3 ρ _{w} g}{T}

JEE Main 2021

LEVELJEE Main

A soap bubble of radius 3 cm is formed inside the another soap bubble of radius 6 cm. The radius of an equivalent soap bubble which has the same excess pressure as inside the smaller bubble with respect to the atmospheric pressure is ........ cm.

JEE Main 2020

LEVELJEE Main

Pressure inside two soap bubbles are $1.01 atm$ and $1.02 atm$ , respectively. The ratio of their volume is

(A)

4 : 1

(B)

0.8 : 1

(C)

8 : 1

(D)

2 : 1

JEE Main 2013

LEVELJEE Advanced

Assume that a drop of liquid evaporates by decrease in its surface energy, so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is $T$ , density of liquid is $ρ$ and $L$ is its latent heat of vaporisation.

(A)

\frac{ρ L}{T}

(B)

\frac{T}{ρ L}

(C)

\frac{T}{ρ L}

(D)

\frac{2 T}{ρ L}

JEE Main 2019

LEVELJEE Advanced

A soap bubble, blown by a mechanical pump at the mouth of a tube, increases in volume, with time, at a constant rate. The graph that correctly depicts the time dependence of pressure inside the bubble is given by

A small spherical droplet of density $d$ is floating exactly half immersed in a liquid of density $ρ$ and surface tension $T$ . The radius of the droplet is (take note that the surface tension applies an upward force on the droplet)

(A)

r = \frac{3 T}{( 2 d - ρ ) g}

(B)

r = \frac{T}{( d - ρ ) g}

(C)

r = \frac{T}{( d + ρ ) g}

(D)

r = \frac{2 T}{3 ( d + ρ ) g}

JEE Main 2021

LEVELJEE Advanced

A large number of water drops, each of radius $r$ , combine to have a drop of radius $R$ . If the surface tension is $T$ and mechanical equivalent of heat is $J$ , the rise in heat energy per unit volume will be

(A)

\frac{2 T}{J} (\frac{1}{r} - \frac{1}{R})

(B)

\frac{2 T}{r J}

(C)

\frac{3 T}{r J}

(D)

\frac{3 T}{J} (\frac{1}{r} - \frac{1}{R})

JEE Main 2019

LEVELJEE Main

If $M$ is the mass of water that rises in a capillary tube of radius $r$ , then mass of water which will rise in a capillary tube of radius $2 r$ is

(A)

2 M

(B)

4 M

(C)

\frac{M}{2}

(D)

M

JEE Main 2019

LEVELJEE Advanced

The ratio of surface tensions of mercury and water is given to be $7.5$ while the ratio of their densities is $13.6$ . Their contact angles with glass are close to $13 5^{\circ}$ and $0^{\circ}$ , respectively. It is observed that mercury gets depressed by an amount $h$ in a capillary tube of radius $r_{1}$ , while water rises by the same amount $h$ in a capillary tube of radius $r_{2}$ . The ratio $(r_{1} / r_{2})$ , is then close to

(A)

3/5

(B)

2/3

(C)

2/5

(D)

4/5

JEE Main 2021

LEVELJEE Main

When two soap bubbles of radii $a$ and $b (b > a)$ coalesce, the radius of curvature of common surface is

(A)

\frac{ab}{b - a}

(B)

\frac{a + b}{ab}

(C)

\frac{b - a}{ab}

(D)

\frac{ab}{a + b}

JEE Main 2004

LEVELJEE Main

If two soap bubbles of different radii are connected by a tube

(A)

air flows from the bigger bubble to the smaller bubble till the sizes become equal

(B)

air flows from bigger bubble to the smaller bubble till the sizes are interchanged

(C)

air flows from the smaller bubble to the bigger

(D)

there is no flow of air

LEVELJEE Main

A 20 cm long capillary tube is dipped in water. The water rises upto 8 cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be

When a long glass capillary tube of radius $0.015 cm$ is dipped in a liquid, the liquid rises to a height of $15 cm$ within it. If the contact angle between the liquid and glass is close to $0^{\circ}$ , the surface tension of the liquid, (in millinewton $m^{- 1}$ ) to the nearest integer is (Take, $ρ_{(liquid)} = 900 kgm^{- 3}, g = 10 ms^{- 2}$ )

JEE Main 2020

LEVELJEE Advanced

A capillary tube made of glass of radius $0.15 mm$ is dipped vertically in a beaker filled with methylene iodide, which rises to height $h$ in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opposite sides of the capillary) make an angle of $6 0^{\circ}$ with one another. Then, $h$ is close to (Given, surface tension $= 0.05 Nm^{- 1}$ , density $= 667 kg m^{- 3}$ and $g = 10 ms^{- 2}$ )

Two mercury drops (each of radius $r$ ) merge to form a bigger drop. The surface energy of the bigger drop, if $T$ is the surface tension, is

(A)

2^{5/3} π r^{2} T

(B)

4 π r^{2} T

(C)

2 π r^{2} T

(D)

2^{8/3} π r^{2} T

JEE Main 2021

LEVELJEE Main

Two spherical soap bubbles of radii $r_{1}$ and $r_{2}$ in vacuum combine under isothermal conditions. The resulting bubble has a radius equal to

(A)

\frac{r _{1} r _{2}}{r _{1} + r _{2}}

(B)

r_{1} r_{2}

(C)

r_{1}^{2} + r_{2}^{2}

(D)

\frac{r _{1} + r _{2}}{2}

JEE Main 2011

LEVELJEE Main

Work done in increasing the size of a soap bubble from radius of $3 cm$ to $5 cm$ is nearly (surface tension of soap solution = $0.03 Nm^{- 1}$ )

(A)

0.2 π mJ

(B)

2 π mJ

(C)

0.4 π mJ

(D)

4 π mJ

JEE Main 2021

LEVELJEE Advanced

Two narrow bores of diameter $5.0 mm$ and $8.0 mm$ are joined together to form a U-shaped tube open at both ends. If this U-tube contains water, what is the difference in the level of two limbs of the tube. [Take surface tension of water $T = 7.3 \times 1 0^{- 2} Nm^{- 1}$ , angle of contact $= 0$ , $g = 10 ms^{- 2}$ and density of water $= 1.0 \times 1 0^{3} kg m^{- 3}$ ]

A capillary tube (A) is dipped in water. Another identical tube (B) is dipped in a soap-water solution. Which of the following shows the relative nature of the liquid columns in the two tubes?

Two small drops of mercury each of radius $R$ coalesce to form a single large drop. The ratio of total surface energy before and after the change is

(A)

2^{\frac{1}{3}} : 1

(B)

1 : 2^{\frac{1}{3}}

(C)

2 : 1

(D)

1 : 2

LEVELJEE Main

A thin liquid film formed between a U-shaped wire and a light slider supports a weight of $1.5 \times 1 0^{- 2} N$ (see figure). The length of the slider is $30 cm$ and its weight negligible. The surface tension of the liquid film is

(A)

0.0125 Nm^{- 1}

(B)

0.1 Nm^{- 1}

(C)

0.05 Nm^{- 1}

(D)

0.025 Nm^{- 1}

JEE Advanced 2009

LEVELJEE Advanced

Two soap bubbles A and B are kept in a closed chamber where the air is maintained at pressure $8 Nm^{- 2}$ . The radii of bubbles A and B are $2 cm$ and $4 cm$ , respectively. Surface tension of the soap-water used to make bubbles is $0.04 Nm^{- 1}$ . Find the ratio $\frac{n _{B}}{n _{A}}$ , where $n_{A}$ and $n_{B}$ are the number of moles of air in bubbles A and B, respectively. [Neglect the effect of gravity]

JEE Advanced (2008)

LEVELJEE Main

A glass tube of uniform internal radius ( $r$ ) has a valve separating the two identical ends. Initially, the valve is in a tightly closed position. End 1 has a hemispherical soap bubble of radius $r$ . End 2 has sub-hemispherical soap bubble as shown in figure. Just after opening the valve.

(A)

air from end 1 flows towards end 2. No change in the volume of the soap bubbles

(B)

air from end 1 flows towards end 2. Volume of the soap bubble at end 1 decreases

(C)

no change occurs

(D)

air from end 2 flows towards end 1. Volume of the soap bubble at end 1 increases

JEE Advanced 2003

LEVELJEE Advanced

A soap bubble is being blown at the end of very narrow tube of radius $b$ . Air (density $ρ$ ) moves with a velocity $v$ inside the tube and comes to rest inside the bubble. The surface tension of the soap solution is $T$ . After sometime the bubble, having grown to radius $r$ separates from the tube. Find the value of $r$ . Assume that $r ≫ b$ so, that you can consider the air to be falling normally on the bubble's surface.

JEE Advanced 2013

LEVELJEE Main

Assume that a drop of liquid evaporates by decrease in its surface energy, so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is $T$ , density of liquid is $ρ$ and $L$ is its latent heat of vaporisation

(A)

\frac{ρ L}{T}

(B)

\frac{T}{ρ L}

(C)

\frac{T}{ρ L}

(D)

\frac{2 T}{ρ L}

A soap bubble of radius 3 cm is formed inside the another soap bubble of radius 6 cm. The radius of an equivalent soap bubble which has the same excess pressure as inside the smaller bubble with respect to the atmospheric pressure is ........ cm.

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Pressure inside two soap bubbles are 1.01 atm and 1.02 atm, respectively. The ratio of their volume is

A soap bubble, blown by a mechanical pump at the mouth of a tube, increases in volume, with time, at a constant rate. The graph that correctly depicts the time dependence of pressure inside the bubble is given by

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } If M is the mass of water that rises in a capillary tube of radius r, then mass of water which will rise in a capillary tube of radius 2r is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } When two soap bubbles of radii a and b(b>a) coalesce, the radius of curvature of common surface is

If two soap bubbles of different radii are connected by a tube

A 20 cm long capillary tube is dipped in water. The water rises upto 8 cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Two mercury drops (each of radius r) merge to form a bigger drop. The surface energy of the bigger drop, if T is the surface tension, is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Two spherical soap bubbles of radii r1​ and r2​ in vacuum combine under isothermal conditions. The resulting bubble has a radius equal to

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Work done in increasing the size of a soap bubble from radius of 3 cm to 5 cm is nearly (surface tension of soap solution = 0.03 Nm−1)

A capillary tube (A) is dipped in water. Another identical tube (B) is dipped in a soap-water solution. Which of the following shows the relative nature of the liquid columns in the two tubes?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Two small drops of mercury each of radius R coalesce to form a single large drop. The ratio of total surface energy before and after the change is

Pressure inside two soap bubbles are $1.01 atm$ and $1.02 atm$ , respectively. The ratio of their volume is

If $M$ is the mass of water that rises in a capillary tube of radius $r$ , then mass of water which will rise in a capillary tube of radius $2 r$ is

When two soap bubbles of radii $a$ and $b (b > a)$ coalesce, the radius of curvature of common surface is

Two mercury drops (each of radius $r$ ) merge to form a bigger drop. The surface energy of the bigger drop, if $T$ is the surface tension, is

Two spherical soap bubbles of radii $r_{1}$ and $r_{2}$ in vacuum combine under isothermal conditions. The resulting bubble has a radius equal to

Work done in increasing the size of a soap bubble from radius of $3 cm$ to $5 cm$ is nearly (surface tension of soap solution = $0.03 Nm^{- 1}$ )

Two small drops of mercury each of radius $R$ coalesce to form a single large drop. The ratio of total surface energy before and after the change is