A long silver teaspoon is placed in a cup filled with hot tea. After some time, the exposed end (the end which is not dipped in tea) of the spoon becomes hot even without direct contact with the tea. This phenomenon can be explained mainly by

Options

A. Conduction
B. Reflection
C. Radiation
D. Thermal expansion

Answer

To solve the question about why the exposed end of a silver teaspoon becomes hot after being placed in hot tea, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- A long silver teaspoon is placed in a cup of hot tea. The spoon has two ends: one end is submerged in the hot tea, and the other end is exposed to the air.

2. **Properties of Silver**:
- Silver is a metal and is known for its excellent thermal conductivity. This means it can efficiently transfer heat from one part of the spoon to another.

3. **Heat Transfer Mechanism**:
- The heat from the hot tea is conducted through the part of the spoon that is submerged. The particles in the hot tea vibrate more vigorously due to their higher temperature, and as they come into contact with the submerged end of the spoon, they transfer some of their energy to the spoon.

4. **Conduction Process**:
- As the submerged end of the spoon heats up, the particles in that section of the spoon begin to vibrate more. These vibrating particles then transfer their energy to adjacent particles in the spoon through collisions, causing the heat to travel along the length of the spoon.

5. **Heating the Exposed End**:
- Eventually, this process of conduction continues along the length of the spoon, causing the exposed end (the end not in contact with the tea) to also become hot. This occurs despite the exposed end not being in direct contact with the hot tea.

6. **Conclusion**:
- The phenomenon can be explained mainly by **conduction**, which is the transfer of heat through a material without the movement of the material itself.

### Final Answer:
The exposed end of the silver teaspoon becomes hot due to **conduction**.

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