What does the contraction of RADAR stand for?

RADAR is an acronym that stands for "Radio Detection and Ranging." This term accurately reflects the primary functions of radar technology. It utilizes radio waves to detect the presence, distance, and speed of objects, such as aircraft, ships, and weather conditions, by analyzing the time it takes for the radio waves to return after bouncing off an object.

The term 'detection' refers to the radar system's ability to identify and track objects, while 'ranging' indicates its capacity to measure the distance to those objects. This combination of features has made radar an essential tool in various applications, including navigation, air traffic control, and military operations.

The other options do not accurately describe what RADAR stands for. They either incorrectly incorporate elements of the acronym or omit the key function of ranging, which is critical to understanding how radar operates.