Which of the following statements is NOT correct about surface tension?
At room temperature, surface tension of water is less than ethyl alcohol.
The correct answer is the surface tension of water at room temperature is less than that of ethyl alcohol.
Key Points
- Surface tension is actually typically measured in dynes/cm, which indicates the force required to break a film of 1 cm length. Thus, option 1 is correct.
- Due to surface tension, the shape of a water droplet is spherical.Thus, option 2 is also correct.
- The spherical shape is a result of surface tension minimizing the surface area of the droplet, as a sphere is the shape that has the least surface area for a given volume.
- Contrary to statement 3, at room temperature, the surface tension of water is actually greater than that of ethyl alcohol. For example, at 20°C, the surface tension of water is 72.8 dynes/cm, while the surface tension of ethyl alcohol is 22.3 dynes/cm.
- The cohesive forces between liquid molecules are actually responsible for the phenomenon known as surface tension. These forces cause the liquid to behave as if it is covered by a stretched elastic sheet, a property known as surface tension. Thus, option 4 is also correct.
Important Questions from Surface Tension
If a liquid droplet and a soap bubble are formed from the same liquid and have the same radius $R$, how does the excess pressure inside the soap bubble ($\Delta P_{bubble}$) compare to the excess pressure inside the liquid droplet ($\Delta P_{droplet}$)?
Mercury does NOT wet the glass. This is due to the property of the liquid known as
________ is a surface phenomenon.
A liquid drop is spherical in shape due to
The property of a fluid which enables it to resist tensile stress is known as
