What is defined as a loss in signal amplitude that occurs as a signal passes through a transmission medium?

Attenuation is defined as the reduction in signal amplitude that takes place as a signal travels through a transmission medium. This phenomenon can occur due to various factors such as the nature of the medium, distance, and any obstructions the signal encounters along its path. As the signal weakens, it becomes more challenging for the receiving end to interpret the data accurately, potentially leading to signal degradation. Understanding attenuation is crucial for designing effective communication systems, as it informs engineers and technicians about the need for signal boosters or repeaters to maintain signal quality over long distances.

In the context of the other options, interference typically refers to the disruption caused by other signals, leading to a decrease in clarity rather than a direct loss of amplitude. Reflection deals with the bouncing back of signals when they hit a barrier, which can influence signal strength but isn't solely about amplitude loss. Distortion is about the alteration in waveform or the integrity of the signal, which can occur for various reasons, including but not limited to attenuation.

Thus, the choice of attenuation accurately addresses the specific scenario of loss in signal amplitude as the signal moves through a medium.