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Liquid water and ice emit radiation at a higher rate than water vapour (see graph above). Water at the top of the troposphere, particularly in liquid and solid states, cools as it emits net photons to space. Neighboring gas molecules other than water (e.g. nitrogen) are cooled by passing their heat kinetically to the water.
The penetration depth of X-rays in water as function of photon energy. Penetration depth is a measure of how deep light or any electromagnetic radiation can penetrate into a material. It is defined as the depth at which the intensity of the radiation inside the material falls to 1/ e (about 37%) of its original value at (or more properly, just ...
Once that happens, radiation can travel far enough that the local emission, B λ (T), can differ from the absorption of incoming I λ. The altitude where the transition to semi-transparency occurs is referred to as the "effective emission altitude" or "effective radiating level." Thermal radiation from this altitude is able to escape to space.
The rays or waves may be diffracted, refracted, reflected, or absorbed by the atmosphere and obstructions with material and generally cannot travel over the horizon or behind obstacles. In contrast to line-of-sight propagation, at low frequency (below approximately 3 MHz ) due to diffraction , radio waves can travel as ground waves , which ...
An overview of absorption of electromagnetic radiation.This example shows the general principle using visible light as a specific example. A white light source—emitting light of multiple wavelengths—is focused on a sample (the pairs of complementary colors are indicated by the yellow dotted lines).
Ionizing radiation creates high-speed electrons in a material and breaks chemical bonds, but after these electrons collide many times with other atoms eventually most of the energy becomes thermal energy all in a tiny fraction of a second. This process makes ionizing radiation far more dangerous per unit of energy than non-ionizing radiation.
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
Beta radiation from linac accelerators is far more energetic and penetrating than natural beta radiation. It is sometimes used therapeutically in radiotherapy to treat superficial tumors. Beta-plus (β + ) radiation is the emission of positrons , which are the antimatter form of electrons.