Question

Which statement among the following is the best example of heat energy transfer by conduction?

• A. Heat energy transferred from the bottom to the top of a lake.
• B. Heat energy transferred from the Sun to the Earth.
• C. Heat energy transferred from the bonfire to the people sitting around it.
• D. Heat energy transferred from the surface soil to the rocks below.

Answer 1

The correct option is D Heat energy transferred from the surface soil to the rocks below.

Heat is transferred from the bottom to the top of a lake by movement of water molecules. So this is a case of convection.
When heat is transferred from the Sun to the Earth, the mode of heat transfer is radiation because the major distance between the Sun and the Earth is vacuum i.e no medium.
In case of bonfire, the heat transfer is a mixture of convection and radiation.
Heat transferred from the surface soil to the rocks below is an example of conduction. On a molecular level, the molecules vibrate to transfer the heat from the soils to the rocks below it,