On heating one end of a piece of a metal, the other end becomes hot because of

Options

A. energised electrons moving to the other end
B. minor perturbation in the energy of atoms
C. resistance of the metal
D. mobility of atoms in the metal

Answer

To solve the question "On heating one end of a piece of a metal, the other end becomes hot because of," we will analyze the options provided and understand the underlying principles of heat conduction in metals.

### Step-by-Step Solution:

1. **Understanding Heat Conduction**:
- When one end of a metal rod is heated, the heat energy causes the atoms at that end to vibrate more vigorously. This vibration is a result of the increased kinetic energy of the atoms.

**Hint**: Remember that heat causes atoms to move more energetically.

2. **Role of Free Electrons**:
- Metals contain free electrons that are not bound to any specific atom. When the atoms at the heated end vibrate, these free electrons gain energy and start moving towards the cooler end of the metal rod.

**Hint**: Consider how free electrons contribute to the conduction of heat in metals.

3. **Energy Transfer**:
- As the free electrons move, they collide with neighboring atoms, transferring some of their energy to them. This process continues along the length of the metal rod, causing the entire rod to eventually become hot.

**Hint**: Think about how energy is passed from one particle to another in a conductor.

4. **Analyzing the Options**:
- **Option 1**: Energized electron moving to the other end - This is correct because the movement of energized electrons is responsible for the heat transfer.
- **Option 2**: Minor perturbation in the energy of atom - This is incorrect as it does not adequately explain the heat transfer.
- **Option 3**: Resistance of metal - This is not the reason for the heat transfer; resistance refers to how much a material opposes the flow of current.
- **Option 4**: Mobility of atoms in the metal - While atoms do move, it is primarily the free electrons that facilitate heat transfer, making this option incorrect.

5. **Conclusion**:
- The correct answer is **Option 1**: Energized electron moving to the other end. This explains why the other end of the metal becomes hot when one end is heated.

### Final Answer:
The other end becomes hot because of **energized electrons moving to the other end**.