What is meant by "wavelength" in signal terminology?

Wavelength in signal terminology refers to the physical distance between consecutive points of similar phase in a wave, such as the distance from one peak to the next peak or, as stated in the correct option, the distance from the beginning of the peak to the end of the valley. This concept is crucial in understanding how electromagnetic waves behave and is key to applications in both RADAR and LIDAR, as it determines the resolution and detection capabilities of these technologies.

Wavelength is inversely related to frequency; as the frequency of a wave increases, its wavelength decreases. This characteristic is critical for distinguishing between different types of signals and understanding how they interact with various media. The wavelength influences how well the wave can propagate through different environments and its potential for reflection, diffraction, and interference.

The other options reflect different aspects of wave behavior but do not accurately define wavelength. The number of cycles per second relates to frequency rather than wavelength, while the strength of the signal wave pertains to amplitude. The duration of one complete cycle refers to the period of a wave, which is also distinct from the concept of wavelength. Understanding these distinctions is important for grasping the fundamentals of wave mechanics in the context of RADAR and LIDAR systems.