Question

The mode of heat transfer which does not require a material medium is:

• A. Conduction
• B. Convection
• C. Radiation
• D. Diffusion

Hint:

Heat from the Sun reaches the Earth through {radiation}, proving that no medium is required.

Answer 1

The Correct Option is C

To determine the mode of heat transfer that does not require a material medium, let's consider the three main methods of heat transfer: conduction, convection, and radiation.

1. Conduction: This mode of heat transfer occurs through direct contact between molecules in a material medium. Heat flows from a region of higher temperature to a region of lower temperature within the medium. Therefore, conduction requires a material medium.
2. Convection: Convection involves the movement of a fluid (liquid or gas) carrying heat energy from one place to another. It requires the presence of a fluid medium, so a material medium is necessary for convection.
3. Radiation: Radiation is the transfer of heat in the form of electromagnetic waves. It can occur through a vacuum, as it does not rely on any material medium for the transfer of energy. For example, the heat from the sun reaches the earth through the vacuum of space via radiation.

Based on the explanations above, the correct answer is Radiation, as it is the only mode of heat transfer that does not require a material medium.