Which one of the following .is the mode of heat transfer in which warm material is transported so as to displace a cooler material

Options

A. Conduction only
B. Convection only
C. Radiation
D. Both conduction and convection

Explanation

To solve the question "Which one of the following is the mode of heat transfer in which warm material is transported so as to displace a cooler material?", we need to analyze the different modes of heat transfer: conduction, convection, and radiation.

### Step-by-Step Solution:

1. **Understanding Heat Transfer Modes**:
- **Conduction**: This is the transfer of heat through a material without the movement of the material itself. Heat is transferred from one particle to another through direct contact.
- **Convection**: This involves the movement of warmer material (like a fluid or gas) which carries heat with it. As the warmer material rises, it displaces cooler material, allowing heat to be transferred.
- **Radiation**: This is the transfer of heat in the form of electromagnetic waves. It does not require a medium and can occur in a vacuum.

2. **Identifying the Key Phrase**:
- The question specifies "warm material is transported so as to displace a cooler material." This indicates a movement of material, which is characteristic of convection.

3. **Analyzing the Options**:
- If the options include conduction, convection, and possibly a combination of both, we can eliminate conduction because it does not involve the movement of material.
- Radiation can also be eliminated as it does not involve the transport of material.

4. **Conclusion**:
- Since convection is the only mode of heat transfer that involves the movement of warmer material displacing cooler material, the correct answer is convection.

### Final Answer:
The mode of heat transfer in which warm material is transported so as to displace a cooler material is **Convection**.

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