The waves which propagate in metals are

Options

A. longitudinal
B. transverse
C. both (a) and (b)
D. neither (a) nor (b)

Answer

To solve the question "The waves which propagate in metals are," we need to analyze the types of waves that can travel through metals.

### Step-by-Step Solution:

1. **Understanding Wave Types**:
- Waves can be classified into two main types: longitudinal waves and transverse waves.
- Longitudinal waves are those in which the oscillations occur in the same direction as the wave travels. An example is sound waves.
- Transverse waves are those in which the oscillations occur perpendicular to the direction of wave travel. An example is waves on a stretched string.

2. **Longitudinal Waves in Metals**:
- When a sound wave travels through a metal, it compresses and rarefies the particles of the metal in the direction of the wave.
- This indicates that longitudinal waves can propagate through metals. For example, when you tap on a metal surface, the sound you hear on the other side is due to longitudinal waves traveling through the metal.

3. **Transverse Waves in Metals**:
- If we consider a stretched wire or a metal rod, when a pulse is generated (like plucking a guitar string), the oscillations occur perpendicular to the direction of the wave.
- This means that transverse waves can also propagate through metals.

4. **Conclusion**:
- Since both longitudinal and transverse waves can propagate in metals, we conclude that the correct answer to the question is that both types of waves can travel through metals.

### Final Answer:
The waves which propagate in metals are both longitudinal and transverse waves.