What is the primary distinction between active and passive sonar?

The primary distinction between active and passive sonar lies in their fundamental operational principles. Active sonar operates by emitting sound waves into the water and then listening for echoes that bounce back from objects, such as submarines or the sea floor. This allows the system to calculate the distance and direction of those objects based on how quickly the echoes return.

On the other hand, passive sonar does not send out any signals; instead, it simply listens for sounds that are naturally present in the environment or produced by other vessels or marine life. This can include noises from engines, propellers, or submarines.

This difference in functionality is critical in determining how each type of sonar is used in naval operations. Active sonar is often preferred for situations where active detection and tracking of underwater objects are required, while passive sonar is more about surveillance and intelligence gathering, allowing vessels to maintain stealth.

In contrast, the other options present misleading information regarding the specific uses or applications of active and passive sonar, or make claims that do not accurately describe their fundamental operational principles.