The transmitted signal of the RADAR is considered infinite unless what happens?

The transmitted signal of the RADAR is considered infinite unless it is reflected, refracted, or absorbed. This is because the nature of the RADAR signal is such that it typically continues to propagate until an interaction occurs with an object. When a signal is reflected, refracted, or absorbed, this interaction signifies that the signal is no longer traveling through free space unimpeded; instead, it has encountered matter that alters its energy or trajectory. This interaction effectively limits the range and integrity of the transmitted signal, transforming its characteristics and affecting how it can be received and analyzed.

The other potential scenarios, such as the signal being stationary, experiencing a loss in amplitude, or traveling through a vacuum, do not directly define the conditions under which the signal is considered infinite. A signal can indeed lose amplitude while still being considered infinite, as this pertains more to the energy diminishing over distance rather than to the interactions with matter. Similarly, signals can propagate indefinitely in a vacuum but still require interaction events to be definitively described as finite in practical applications.