What are stationary waves?

Answer

### Step-by-Step Text Solution:

1. **Definition of Stationary Waves**:
Stationary waves, also known as standing waves, are waves that remain in a constant position. They are formed by the superposition of two waves traveling in opposite directions with the same frequency and amplitude.

2. **Formation of Stationary Waves**:
Stationary waves are produced when two waves of the same frequency interfere with each other. One wave travels in the positive direction while the other travels in the negative direction. This interference creates points of constructive and destructive interference.

3. **Characteristics of Stationary Waves**:
- **Nodes**: These are points along the medium where there is no displacement. At these points, the two waves cancel each other out completely, resulting in zero amplitude.
- **Antinodes**: These are points where the displacement is at its maximum. At these points, the two waves reinforce each other, leading to maximum amplitude.

4. **Energy and Momentum Transfer**:
In stationary waves, there is no net transfer of energy or momentum through the medium. The energy is confined to the oscillation of the particles at their respective nodes and antinodes.

5. **Simple Harmonic Motion (SHM)**:
Each point on the string (except for the nodes) oscillates with simple harmonic motion. The particles at the antinodes experience maximum displacement, while those at the nodes remain stationary.

### Summary:
Stationary waves are formed by the interference of two waves traveling in opposite directions with the same frequency. They consist of nodes (points of no displacement) and antinodes (points of maximum displacement), and they do not transfer energy or momentum through the medium.

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