Electromagnetic wave interaction with matter - Higher
Refraction in the atmosphere
The Earth's surface is curved. In order to send Low frequency electromagnetic radiation used to transmit information such as television and radio programmes. over long distances they must be reflected from the Ionised region of the Earth's upper atmosphere., which is part of the Earth's The layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide..
Absorption and transmission of waves
As well as being There is a reflection when waves bounce off a surface. or Deflected from a straight path. Bent., waves can also be Energy is 'taken-in' by the material and the internal energy of the material will increase, eg infrared radiation from the Sun is absorbed by the surface of the Earth. or A wave is passed across or through聽a material聽(medium), eg light waves are transmitted through air, glass and water. when they move from one material to another.
For example, radio waves are transmitted by walls - this explains why these signals can be detected by radios inside a person's house. However, visible light rays are absorbed by walls, which is why windows are needed to allow the Sun's rays into a building. Walls also absorb ultraviolet rays, which is why people don't get sunburnt indoors. The atmosphere absorbs X-rays and gamma rays from space which can cause harm to the human body.