What sends out a pulse that gets reflected back by objects with mass?

• A. Secondary radar
• B. Primary radar
• C. Satellite communication
• D. GPS tracking

Answer: (B)

Primary radar is the correct choice because it operates by transmitting a pulse of radio waves that travel through the atmosphere. When these pulses encounter an object with mass, such as an aircraft or a vehicle, they bounce back, or reflect. The radar system then detects the return signal, which allows it to determine the distance to the object and, in some cases, its speed and direction.

This functioning is a fundamental characteristic of primary radar systems. They are entirely self-sufficient in locating objects without needing any onboard transponder or additional equipment on the target. In aviation, primary radar is essential for detecting aircraft and managing air traffic, especially in situations where a transponder may not be available or functioning correctly.

While secondary radar, satellite communication, and GPS tracking have specific purposes, they do not operate in the same manner as primary radar. Secondary radar relies on transponder signals from aircraft, satellite communications involve transmitting information to and from satellites for longer ranges, and GPS tracking uses satellite signals to determine location but does not utilize pulse reflection to locate objects.