No medium is required for transfer of heat by the process of ____

Answer

**Step-by-Step Solution:**

1. **Understanding Heat Transfer Methods**:
- There are three main methods of heat transfer: conduction, convection, and radiation.

2. **Identifying Medium Requirements**:
- **Conduction**: This method requires a medium (solid, liquid, or gas) for heat transfer. Heat is transferred through direct contact of particles.
- **Convection**: This method also requires a medium, typically a fluid (liquid or gas). Heat is transferred by the movement of the fluid itself.
- **Radiation**: This method does not require any medium. Heat is transferred through electromagnetic waves, such as infrared radiation.

3. **Conclusion**:
- Since conduction and convection both require a medium, the only method of heat transfer that does not require a medium is radiation.

4. **Final Answer**:
- Therefore, the answer to the question is: No medium is required for transfer of heat by the process of **radiation**.

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