Question

What is the reason of rising of oil in the wick in a lamp?
1. Oil is very light
2. Diffusion of oil through wick
3. Capillary action
4. Surface tension

Answer 1

Correct Answer - Option 3 : Capillary action

The correct answer is Capillary action.

• The oil in the wick of an oil lamp rises up due to capillary action.
  • This effect is due to surface tension of liquids.
  • The wick here acts as a capillary tube.
  • Capillary action, or capillarity, is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.
  • The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper, in some non-porous materials such as liquefied carbon fiber, or in a cell.
  • It occurs because of inter-molecular attractive forces between the liquid and solid surrounding surfaces.