MCQ Detailed View

The rise of oil in the wick of an oil lamp is caused by a physical phenomenon called capillary action. Capillary action is a property of liquids where they can flow through narrow spaces, such as the tiny pores in a wick, without the assistance of external forces and even against gravity. This behavior occurs due to the combination of cohesion and adhesion forces in liquids.

Cohesion refers to the attraction between molecules of the same substance, like the oil molecules attracting each other. Adhesion is the attraction between molecules of different substances, in this case, the oil molecules and the fibers of the wick. When the adhesive forces between the liquid and the solid surface are stronger than the cohesive forces within the liquid, the liquid climbs up the narrow space, as happens in the wick of an oil lamp.

Capillary action is not limited to oil lamps; it is an essential concept in many areas of science and daily life. For example, it explains how water moves through the roots and stems of plants, allowing nutrients to reach leaves. It also occurs in thin tubes, paper towels, and porous materials. The height to which a liquid can rise depends on the diameter of the tube or wick, the surface tension of the liquid, and the angle of contact between the liquid and the solid surface.

In an oil lamp, capillary action draws oil upward from the reservoir into the wick, ensuring a continuous supply of fuel to the flame. Without this property, the wick would not be able to transport oil, and the lamp would not function efficiently. This demonstrates how fundamental physics concepts like capillary action directly influence simple everyday devices, combining fluid mechanics and surface tension principles.