Radiation has frequency {radiation frequency}.
Deceleration as electrons hit metal makes radiation {Bremsstrahlung radiation}| with wavelength 10^-12 meters.
Beta-particle electrons, with velocity higher than light speed in water, emit blue light {Cerenkov radiation}| {blue glow} as shock waves when they enter water. Water surrounding nuclear-reactor cores, which emit high-velocity electrons, has blue glow.
process
Electrons traveling in water use some energy to polarize water molecules along travel direction. After electrons pass, polarized water molecules emit light. If electrons travel slower than light speed in water, emitted radiation appears low, because electromagnetic waves emitted by molecules along path are random and destructively interfere. If electrons travel faster than light speed in water, emitted radiation appears high because electromagnetic waves emitted by molecules along path are shock waves that constructively interfere.
Infrared-light rotational and vibrational energies cause differences in visible light reflected from molecules {Raman scattering}|.
In atmosphere, secondary cosmic rays {spallation}| arise if cosmic ray hits atomic nucleus.
Charged particles accelerated by spiraling in magnetic field can emit microwaves {synchrotron radiation}|. Synchrotron radiation happens when electric field is parallel to electron-orbit plane.
Electromagnetic radiation has frequency range and wavelength range {spectrum, light}|.
low frequency
electric wave. radio wave. short wave. very-high-frequency TV wave. ultra-high-frequency TV wave. microwave radiation. infrared ray.
visible
Visible light is 4 x 10^14 Hz with wavelength 6.8 x 10^-7 meters for red light, orange, yellow, wavelength 5.5 x 10^-7 meters for yellow-green, green, wavelength 4.4 x 10^-7 meters for blue light, indigo or ultramarine, and 7.5 x 10^14 Hz with wavelength 4.1 x 10^-7 meters for violet light.
Violet is 380 to 435 nanometer, with middle at 408 nanometer. Blue is 435 to 500 nanometer, with middle at 463 nanometer. Cyan is 500 to -520 nanometer, with middle at 510 nanometer. Green is 520 to 565 nanometer, with middle at 543 nanometer. Yellow is 565 to 590 nanometer, with middle at 583 nanometer. Orange is 590 to 625 nanometer, with middle at 608 nanometer. Red is 625 to 740 nanometer, with middle at 683 nanometer.
high frequency
near ultraviolet. ultraviolet. far ultraviolet. X ray. gamma ray. secondary cosmic ray. cosmic ray. primary cosmic ray.
Smallest frequencies and longest wavelengths {electric wave}| are 3 to 60 Hz and 10^8 to 5 x 10^6 meters.
Next smallest frequency and wavelength {radio wave}| are 10^3 Hz and 3 x 10^5 meters.
High-frequency radio waves {short wave}| are for global communication.
Typical TV frequencies and wavelengths {very high frequency TV wave}| (VHF) are 10^8 Hz and 3 meters.
higher TV frequencies and wavelengths {ultra high frequency TV wave}| (UHF).
frequencies below infrared {microwave radiation}|.
Heat-ray {infrared}| frequency is 10^12 Hz, with wavelength 3 x 10^-4 meters.
Light {visible light}| can have wavelength 400 nm to 700 nm. Visible light has same wavelengths as diameters of, and energy changes in, atoms and molecules. Matching diameters allows people to focus on objects, because light is not too diffracting or too strong. Matching energy changes allows absorption, emission, and chemical reactions.
Smallest visible-light frequency {red light}| is 4 x 10^14 Hz, with wavelength 6.8 x 10^-7 meters.
Highest visible-light frequency {violet light}| is 7.5 x 10^14 Hz, with wavelength 4.1 x 10^-7 meters.
higher frequency than violet {ultraviolet}|.
Light {far ultraviolet}| {black light} can have frequency 1.5 x 10^15 Hz and wavelength 2 x 10^-7 meters.
higher frequency than far ultraviolet {X ray}| {x ray}.
Next-to-highest frequency {gamma ray, spectrum}| is 10^23 Hz, with wavelength 3 x 10^-15 meters.
Highest frequency {cosmic ray}| {primary cosmic ray} is 10^25 Hz, with wavelength 3 x 10^-17 meters. Quasars and powerful energy sources make cosmic radiation.
Light {monochromatic light}| can have one wavelength.
Light {polychromatic light}| can have many wavelengths.
Magenta, yellow, and green pigments {primary pigment}| mix to make black.
Variations {dichroism}| in absorbed-light color can depend on light-polarization direction. Dichroism indicates molecule orientation, which can be linear, circular {circular dichroism}, or elliptical. Microvilli rhabdom can lie parallel, exhibit dichroism, and detect polarized-light polarization plane.
5-Physics-Wave-Electromagnetic
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Date Modified: 2022.0225