If visible, what shape would a RADAR beam most closely resemble?

A RADAR beam typically resembles a cigar-shaped core, which reflects how the radar wave propagates and focuses. In practical terms, this shape arises due to the directional nature of RADAR systems, which often emit waves in a narrow beam. The beam expands gradually as it moves away from the antenna, forming a shape that resembles a long cylinder or cigar.

This focused beam allows RADAR to detect objects at considerable distances, as the energy is concentrated in a specific direction rather than being dispersed in all directions. This characteristic is essential for RADAR applications in aviation, maritime, and automotive fields, where pinpointing the location of objects is crucial for safety and navigation purposes.

In contrast, other options like a circular disk, square prism, or spherical shape do not adequately capture the specific propagation characteristics of a RADAR beam. These shapes imply a more uniform or omnidirectional spread of energy, which does not align with how RADAR systems are designed to operate, emphasizing the importance of understanding the unique cigar-like shape of the RADAR beam in the context of its functionality.