AM (Amplitude Modulation) and FM (Frequency Modulation) waves are both forms of electromagnetic waves and travel in a manner similar to other types of electromagnetic radiation, such as light.
Electromagnetic waves, including AM and FM waves, propagate through space by oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation. These waves do not require a physical medium and can travel through a vacuum, just like light waves.
AM and FM waves primarily propagate in a straight line from the transmitting antenna. They can travel through the atmosphere and space, and their behavior is affected by various factors such as the frequency of the wave, the power of the transmission, and the presence of obstacles or interference.
However, unlike light waves, AM and FM waves are not restricted to traveling just along the surface of the Earth. They can propagate both along the Earth's surface and through the atmosphere. The behavior of these waves is influenced by factors like the frequency, power, and antenna height, which can affect their range and coverage.
AM waves, with their varying amplitude, tend to travel longer distances due to their ability to interact with the Earth's surface and bounce off it. This characteristic allows AM radio signals to reach larger coverage areas, especially during the nighttime when ionospheric reflections enhance their range.
FM waves, with their varying frequency, are more line-of-sight in nature. They are less prone to bouncing off the Earth's surface or obstacles and are generally affected by factors like terrain and buildings. FM radio signals typically have a shorter range compared to AM signals, but they provide better sound quality and are less susceptible to interference.
In summary, AM and FM waves travel primarily in a straight line from the transmitting antenna, and their propagation is influenced by various factors. While they can travel through the atmosphere and space like light waves, they are not restricted to traveling only along the Earth's surface.