The F2 layer is a part of the Earth's ionosphere, which is a region of the atmosphere filled with charged particles. It is located approximately 200 to 400 kilometers above the Earth's surface and plays a crucial role in radio wave propagation. The F2 layer is the highest layer of the ionosphere and is most active during the daytime when solar radiation ionizes the atmosphere. This layer is important for long-distance communication, as it reflects radio waves back to the Earth's surface. The F2 layer's density and height can vary based on solar activity, affecting signals used in technologies like GPS and satellite communication.