PADI Divemaster Certification Practice Exam

A wave breaks when the depth is what proportion of its height?

1. 0.5

2. 1.0

3. 1.3

4. 2.0

The correct answer is: 1.3

A wave breaks when the water depth is approximately 1.3 times the wave height. This relationship arises from the interaction of gravity, the wave's energy, and the depth of the water. As a wave travels through deeper water, it can maintain its energy and shape. However, as it approaches shallower depths, the wave’s base slows down due to friction with the ocean floor, while the top of the wave continues moving at a higher speed. This disparity causes the wave to become steep and eventually break. The proportional relationship of 1.3 to 1 is derived from the critical point at which the wave's steepness exceeds a certain threshold, resulting in breaking. Understanding this ratio is crucial for divers and surf enthusiasts alike, as it impacts wave behavior and safety during diving and water activities.