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

Step 1: Understanding heat transfer modes.
Heat transfer occurs through three primary modes: conduction, convection, and radiation. Each mode has different physical mechanisms.
Step 2: Explanation of radiation.
Radiation is the transfer of heat energy in the form of electromagnetic waves. Since electromagnetic waves can travel through a vacuum, radiation does not require any material medium.
Step 3: Comparison with other modes.
- Conduction requires direct contact between molecules.
- Convection requires fluid motion and a material medium.
- Diffusion is related to mass transfer, not heat transfer.
Step 4: Analysis of options.
(A) Conduction: Requires a solid or material medium.
(B) Convection: Requires a fluid medium.
(C) Radiation: Correct — Can occur through vacuum.
(D) Diffusion: Not a mode of heat transfer.
Step 5: Conclusion.
Since radiation can transfer heat without any material medium, it is the correct answer.