A spherical drop of water has a radius of 1 mm. If the surface tension of water is N/m, the difference in pressures inside and outside the spherical drop is:
1. | 35 N / m2 | 2. | 70 N / m2 |
3. | 140 N / m2 | 4. | Zero |
The property of surface tension of the liquid is due to:
1. | the gravitational force of attraction between the molecules. |
2. | the cohesive forces between the molecules. |
3. | the adhesive force between the molecules. |
4. | the formation of ionic bonds between the molecules. |
In order to float a ring of area 0.04 in a liquid of surface tension 75 N/m, the required surface energy will be:
1. | 3 J | 2. | 6.5 J |
3. | 1.5 J | 4. | 4 J |
If the excess pressure inside a soap bubble is balanced by an oil column of height of \(2\) mm, then the surface tension of the soap solution will be: (radius of the soap bubble, \(r=1\) cm and density of oil, \(d=0.8\) gm/cm3)
1. \(3.9\) N/m
2.
3.
4. \(3.9\) dyne/m
The energy needed to break a drop of radius R into n drops of radii r is given by:
1. | 2. | ||
3. | 4. |
Two soap bubbles are connected by a tube as shown in the figure. Which of the following statement is true?
1. | The volume of A will increase. | 2. | The volume of A will remain constant. |
3. | The volume of B will increase. | 4. | The volume of B will decrease. |
Small droplets of liquid are usually more spherical in shape than the larger drops of the same liquid because:
1. | the force of surface tension is equal and opposite to the force of gravity. |
2. | the force of surface tension predominates the force of gravity. |
3. | the force of gravity predominates the force of surface tension. |
4. | the force of gravity and the force of surface tension act in the same direction and are equal. |
A wooden stick 2 m long is floating on the surface of the water. The surface tension of water is 0.07 N/m. By putting soap solution on one side of the stick, the surface tension is reduced to 0.06 N/m. The net force on the stick due to surface tension will be:
1. | 0.07 N | 2. | 0.06 N |
3. | 0.01 N | 4. | 0.02 N |
A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then:\(\text { Energy }=4 V T\left(\frac{1}{r}-\frac{1}{R}\right) \text { is released } \)
1. | Energy = \(4 V T\left(\frac{1}{r}-\frac{1}{R}\right)\) is released | 2. | Energy =\(3 V T\left(\frac{1}{r}+\frac{1}{R}\right)\) is released |
3. | Energy =\(3 V T\left(\frac{1}{r}-\frac{1}{R}\right)\) is released | 4. | Energy is neither released nor absorbed |
The surface tension of a liquid is \(5\) N m-1. If a film is held on a ring of area \(0.02\) , then its total surface energy is:
1. \(3\times\) J
2. \(2\times\) J
3. \(3\times\) J
4. J