The question asks for an example illustrating the concept of surface tension.

Surface Tension Phenomena Explained

Surface tension is a property of liquid surfaces that causes them to behave like a stretched elastic membrane. It arises from the cohesive forces between liquid molecules, leading the liquid to minimize its surface area.

Analyzing the Options

• Rain drops: Due to surface tension, water droplets tend to form a spherical shape. A sphere has the smallest surface area to volume ratio, which liquids naturally strive for under the influence of surface tension.
• Rise of sap in a tree: This phenomenon, known as capillary action, is a direct consequence of surface tension. The cohesive forces within the sap and adhesive forces between the sap and the xylem walls cause the liquid to rise against gravity in narrow tubes (like xylem vessels).
• Break up of liquid jets: When a liquid exits a nozzle, surface tension causes the continuous jet to break up into small, roughly spherical droplets. This occurs because the formation of droplets minimizes the total surface area exposed to the air.

Conclusion

All the listed phenomena – the shape of raindrops, the rise of sap in trees (capillary action), and the breakup of liquid jets into droplets – are direct results of surface tension acting on liquids. Therefore, all options provided are correct examples.

The correct answer is Option D because surface tension is responsible for all the phenomena listed.