Which of the following absorbs RADAR energy?

The absorption of RADAR energy is closely associated with the material composition and structure of various substances. Tall grass and leaves possess the characteristics necessary for absorbing RADAR signals due to their natural, organic composition and varying densities. Unlike metals, which typically reflect RADAR energy, or clear water and air, which do not hinder RADAR signal travel significantly, grass and leaves can disrupt the RADAR waves, leading to scattering and absorption of the energy as they interact with the electromagnetic fields produced.

The other materials mentioned, while they interact with RADAR energy in various ways, primarily reflect it rather than absorb it. For instance, glass and plastic are often transparent to RADAR signals, allowing them to pass through with minimal interaction. Clear water and air, similarly, do not significantly absorb RADAR energy; instead, they typically allow for transmission of signals. Metal and concrete, on the other hand, are materials that primarily reflect RADAR energy, leading to signals bouncing back, rather than being absorbed.

In the context of RADAR operations, understanding which materials absorb signals helps in interpreting RADAR returns and improving the efficacy of the system in various environments. This knowledge is crucial for radar operators in determining the visibility of objects and the overall effectiveness of RADAR detection.