Question 75Navigation General

The correct answer is C) bobbing a light. This process is called "bobbing a light" because the light appears to be "bobbing" up and down as the observer's eye height is raised and lowered. When the light is first seen on the horizon, it will disappear again if the height of the observer's eye is immediately lowered by several feet. When the eye is then raised back to its former height, the light will again become visible. This phenomenon is due to the curvature of the Earth and the visual range of the light, which depends on the observer's eye height. The other answer choices are incorrect because "raising a light" (A) does not accurately describe the process, "obscuring a light" (B) implies the light is being intentionally blocked, and "checking a light" (D) does not capture the specific concept of the light appearing to "bob" up and down.