Convection of heat takes place in

Options

A. metals only
B. liquids only
C. gases only
D. liquids and gases

Explanation

### Step-by-Step Solution:

1. **Understanding Heat Transfer**:
- Heat transfer occurs through three main processes: conduction, convection, and radiation. Each process has its own mechanism of transferring heat.

2. **Defining Convection**:
- Convection is a mode of heat transfer that occurs in fluids (liquids and gases) where the heat is carried by the movement of the fluid itself. This means that the heat is transferred without any solid contact between the heat source and the fluid.

3. **Examples of Convection**:
- An example of convection can be seen when heating water. If you place an electric furnace above the water, the heat from the furnace warms the surface of the water. The warmer, less dense water rises, while the cooler, denser water sinks, creating a circulation pattern. This demonstrates how heat is transferred through the movement of the liquid.

4. **Why Convection Does Not Occur in Solids**:
- In solids, the atoms and molecules are tightly packed and cannot move freely. Therefore, when heat is applied to a solid, it cannot transfer through convection because there is no movement of particles to carry the heat away.

5. **Conclusion**:
- Based on the understanding of convection and its characteristics, we conclude that convection of heat takes place in **liquids and gases**. Therefore, the correct answer to the question is that convection occurs in **liquids and gases only**.

### Final Answer:
Convection of heat takes place in **liquids and gases**.

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