The correct full form of 'Radar' is:

Question

Accepted Answer

The correct full form of 'Radar' is **Radio Detection and Ranging** because:

*   **Radio:** Radar systems use radio waves to transmit signals. These radio waves are electromagnetic waves within a specific frequency range.
*   **Detection:** The primary function of radar is to detect the presence of objects (targets) within its range. This is achieved by analyzing the reflected radio waves.
*   **and:** This is a simple conjunction connecting the two main functions.
*   **Ranging:** Radar determines the distance (range) to the detected objects by measuring the time it takes for the radio waves to travel to the object and return.

Therefore, "Radio Detection and Ranging" accurately describes the fundamental principles and operations of a radar system.

Now, let's explain why the other options are incorrect:

*   **Option 1: Radio Detection Aperture System:** While radar systems *can* use synthetic aperture techniques (SAR), the term "aperture system" is not a core part of the fundamental definition of radar. Radar's primary function is detection and ranging, not specifically creating an aperture.

*   **Option 2: Real Aperture Detection Ranging:** Similar to Option 1, "Real Aperture" refers to a specific type of radar system (RAR) but isn't the general definition of radar. While it does involve detection and ranging, the "Real Aperture" part is too specific and doesn't encompass all radar systems.

*   **Option 3: Radio and Direction Ranging:** While radar *can* determine the direction of a target, the primary function is *detection* of the target's presence. "Direction" is a secondary piece of information derived from the reflected signal. The core function is to detect *and* range, not just determine direction and range.