Question

Radar is a system that uses radio waves to determine the distance, direction and radial velocity of objects relative to the site. Radar stands for

• A. radio displays and range
• B. radio rays and range
• C. radio distance and range
• D. radio detection and ranging

Hint:

Acronyms in science describe the actual physical function of the technology.
Since the system detects targets and calculates their range (distance) using radio waves, it is logically named Radio Detection And Ranging.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for the correct expansion of the acronym ``Radar''.

Step 2: Key Concepts and Abbreviations:
Radar is an electromagnetic sensor system used to detect, locate, and track objects (such as aircraft, ships, and spacecraft) over long distances.
The name was coined in 1940 by the United States Navy as an acronym describing its core operating principles.

Step 3: Detailed Explanation:

• Acronym Breakdown:
-

RA : Radio (indicating the use of radio frequency waves).
-

D : Detection (referring to finding the presence of an object).
-

A : And (the coordinating conjunction).
-

R : Ranging (referring to measuring the distance to the target).
Combining these, we get:

RAdio

Detection

And

Ranging.

• Evaluating Options: Options A, B, and C are incorrect variations that substitute terms like ``displays'', ``rays'', or ``distance'', which do not represent the standardized historical acronym.


Step 4: Final Answer:
Thus, the correct full form of Radar is ``radio detection and ranging'', corresponding to Option (D).