# Excess Pressure in Bubbles

## Trending Questions

**Q.**Two soap bubbles of radii 4 cm and 5 cm are touching each other over a common surface S1S2 (shown in figure). Then, radius of the common surface will be

- 12 cm
- 20 cm
- 16 cm
- 10 cm

**Q.**A soap bubble of radius R is surrounded by another soap bubble of radius 2R as shown. Taking surface tension = S, the pressure inside the smaller soap bubble, in excess of the atmospheric pressure will be

- 4S4
- 3S4
- 6S4
- None of these

**Q.**The excess pressure inside one soap bubble is three times that inside a second soap bubble, then the ratio of their surface areas is:

- 1:9
- 1:3
- 3:1
- 1:27

**Q.**What should be the pressure inside a air bubble of radius 0.1 mm situated 1 m below the water surface?

(Take surface tension of water T=7.2×10−2 N/m and g=10 m/s2)

- 3.5×105 Pa
- 1.11×105 Pa
- 2.11×105 Pa
- 3×105 Pa

**Q.**A soap bubble of diameter 8 mm is formed in air. If the surface tension of liquid is 30 dyne/cm, then excess pressure inside the soap bubble is

- 150 dyne/cm2
- 300 dyne/cm2
- 3×10−3 dyne/cm2
- 12 dyne/cm2

**Q.**A soap bubble of diameter 10 mm has an excess pressure of 50 N/m2. Find the surface tension of soap solution.

- 0.31 N/m
- 0.063 N/m
- 0.063 N/m2
- 0.031 N/m2

**Q.**

A cubical tank of side $3.0m$is evacuated of air. That is, the number of molecules of air inside the tank is insignificant compared to the number in the same volume outside. The atmospheric pressure is ${10}^{5}Pa$. What is the crushing force exerted by the atmosphere on the tank?

**Q.**A spherical soap bubble of radius 1 cm is formed inside another of radius 3 cm. The radius of a single soap bubble which maintains the same pressure difference as inside the smaller and outside the larger soap bubble is

- 1.33 cm
- 0.75 cm
- 7.5 cm
- 13.3 cm

**Q.**

An air bubble in sphere having 4 cm diameter appears 1 cm from surface nearest to eye when looked along diameter. If _{a}m_{g} = 1.5, the distance of bubble from refracting surface is

**[CPMT 2002]**

1.2 cm

3.2 cm

2.8 cm

1.6 cm

**Q.**What will be the diameter (in mm) of a water droplet, the pressure inside which is 0.05 N/cm2 greater than the outside pressure? (Take surface tension as 0.075 N/m).

- 3
- 0.3
- 0.6
- 6

**Q.**The excess pressure inside a spherical drop of water is four times that of another water drop. Then the mass ratio of the two drops is

- 1:16
- 1:64
- 1:4
- 1:8

**Q.**Pressure inside two soap bubbles of a liquid solution are 1.01 atm and 1.02 atm. Ratio of their volume is

- 4:1
- 8:1
- 1:8
- 1:4

**Q.**A water droplet splits into 27 identical small droplets. The pressure difference between the inner and outer surface of the big droplet will be

- Same as that of smaller droplet
- 1/3 rd of the pressure difference for smaller droplet.
- 1/4 th of the pressure difference for smaller droplet.
- None of these

**Q.**Shown in the figure, is a hollow ice-cream cone (it is open at the top). If its mass is M, radius of its top is R and height H then, its moment of inertia about its axis is:

- MR23
- MR22
- M(R2+H2)4
- MH23

**Q.**Two soap bubbles A and B are kept in a closed chamber where the air is maintained at pressure 8N/m2. 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 N/m. Find the ratio nB/nA, where nA and nB are the number of moles of air in bubbles A and B, respectively.

Given that for a gas, the relation between number of moles and pressure and volume is PV = kn, where k is constant at a particular temperature.

**(IIT-JEE-2009)**

[Neglect the effect of gravity.]

- 6
- 7
- 8
- 9

**Q.**A beaker is filled with liquid solution. A soap bubble of radius 1 mm is formed in the bulk of liquid solution. If surface tension of liquid is 1.6 N/m, find the excess pressure inside the soap bubble.

- 1.6×103 N/m2
- 3.2×103 N/m2
- 0.8×10−3 N/m2
- None of these

**Q.**A soap bubble having radius 1 mm is blown from a detergent solution having a surface tension of 2.5×10−2 N/m. The pressure inside the bubble is equal to the pressure at a point which is Z0 below the free surface of water in a container. Find the value of Z0 . Taking g = 10 m/s2, density of water = 103 kg/m3

- 100 cm
- 10 cm
- 1 cm
- 0.5 cm

**Q.**A spherical drop of water has radius r m. If surface tension of water is 70×10−3 N/m and the pressure difference between inside and outside of the spherical drop is 280 N/m2. Find the value of r.

- 1 mm
- 0.5 mm
- 0.4 mm
- 0.2 mm

**Q.**A beaker is filled with liquid having surface tension 0.07 N/m. If a bubble of radius 0.5 mm is formed at depth h=1 m below the free surface, then find difference between the pressure acting inside the bubble and free surface.

(Density of liquid is 1000 kg /m3)

- 0.28×104 N/m2
- 0.56×104 N/m2
- 1.028×104 N/m2
- 2.014×104 N/m2