Behaviour of Different Wavelengths of Electromagnetic Light
Behaviour of Different Wavelengths of Electromagnetic Light
Electromagnetic Spectrum and Atmosphere
- The electromagnetic spectrum is composed of different types of waves each with differing wavelengths and energy levels.
- The atmosphere interacts with these waves differently, which is fundamental to understanding atmospheric processes.
Ultraviolet Light
- Ultraviolet (UV) light has shorter wavelengths and is more energetic than visible light.
- Most UV light is absorbed by ozone molecules in the stratosphere, protecting us from harmful radiation.
- However, some UV-B reaches the earth’s surface and can cause skin cancer and cataracts in humans.
- UV-C is the most dangerous but is entirely absorbed in the atmosphere.
Visible Light
- Visible light is a small, but important, part of the electromagnetic spectrum that our eyes can detect.
- Visible light passes through the atmosphere to reach the surface, providing the energy needed for photosynthesis.
- The scattering of visible light by particles in the atmosphere gives us blue skies and red sunsets, a phenomenon known as Rayleigh scattering.
Infrared Radiation
- Infrared (IR) radiation has longer wavelengths and lower energy than visible light.
- The atmosphere is semi-transparent to IR, meaning some of it escapes into space, but a significant amount is absorbed and re-emitted by greenhouse gases.
- This re-emission of IR back to Earth results in the greenhouse effect, which helps to maintain Earth’s temperature.
- However, excessive absorption and re-emission by increasing greenhouse gases leads to global warming and climate change.
Radio Waves
- Radio waves have the longest wavelengths and lowest energy of the electromagnetic spectrum.
- Most radio waves pass freely through the Earth’s atmosphere without any interaction, which is why we can use them for long-distance communication.
Summary
Understanding how different wavelengths of electromagnetic light behave in the atmosphere is key to explain a variety of everyday phenomena, from why the sky is blue to why our planet is warming.