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In physiology, thermoception or thermoreception is the sensation and perception of temperature, or more accurately, temperature differences inferred from heat flux.It deals with a series of events and processes required for an organism to receive a temperature stimulus, convert it to a molecular signal, and recognize and characterize the signal in order to trigger an appropriate response.
For example, the temperature modality is registered after heat or cold stimulate a receptor. Some sensory modalities include: light , sound , temperature , taste , pressure , and smell . The type and location of the sensory receptor activated by the stimulus plays the primary role in coding the sensation.
Electromagnetic waves in free space must be solutions of Maxwell's electromagnetic wave equation. Two main classes of solutions are known, namely plane waves and spherical waves. The plane waves may be viewed as the limiting case of spherical waves at a very large (ideally infinite) distance from the source.
Radiation waves may travel in unusual patterns compared to conduction heat flow. Radiation allows waves to travel from a heated body through a cold non-absorbing or partially absorbing medium and reach a warmer body again. [14] An example is the case of the radiation waves that travel from the Sun to the Earth.
The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. Radio waves, at the low-frequency end of the spectrum, have the lowest photon energy and the longest wavelengths—thousands of kilometers, or more.
The above treatment for an incident wave accounts for the radiation pressure experienced by a black (totally absorbing) body. If the wave is specularly reflected, then the recoil due to the reflected wave will further contribute to the radiation pressure. In the case of a perfect reflector, this pressure will be identical to the pressure caused ...
Under these approximations, the dispersion equation for electromagnetic waves includes two free-space modes that can escape the plasma as radiation (radio waves). These are called the ordinary ( o {\displaystyle o} ) and extraordinary ( x {\displaystyle x} ) modes. [ 18 ]
Figure 2. Eigenvalue ε of wave modes of zonal wave number s = 1 vs. normalized frequency ν = ω/Ω where Ω = 7.27 × 10 −5 s −1 is the angular frequency of one solar day. Waves with positive (negative) frequencies propagate to the east (west). The horizontal dashed line is at ε c ≃ 11 and indicates the transition from internal to ...