Explain the terms crest and trough of a wave.

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Crest:**
- A crest is defined as the highest point of a wave. It is the point where the displacement of the medium is at its maximum. In other words, when a wave travels through a medium, the crest represents the peak of the wave where the particles of the medium are displaced the farthest in the upward direction.

2. **Definition of Trough:**
- A trough is the lowest point of a wave. It is the point where the displacement of the medium is at its minimum. This means that at the trough, the particles of the medium are displaced the farthest in the downward direction.

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