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In frequency (and thus energy), UV rays sit between the violet end of the visible spectrum and the X-ray range. The UV wavelength spectrum ranges from 399 nm to 10 nm and is divided into 3 sections: UVA, UVB, and UVC. UV is the lowest energy range energetic enough to ionize atoms, separating electrons from them, and thus causing chemical reactions.
A dispersion relation relates the wavelength or wavenumber of a wave to its frequency. Given the dispersion relation, one can calculate the frequency-dependent phase velocity and group velocity of each sinusoidal component of a wave in the medium, as a function of frequency.
Radiant flux per unit frequency or wavelength. The latter is commonly measured in W⋅nm −1. Φ e,λ [nb 4] watt per metre W/m M⋅L⋅T −3: Radiant intensity: I e,Ω [nb 5] watt per steradian: W/sr: M⋅L 2 ⋅T −3: Radiant flux emitted, reflected, transmitted or received, per unit solid angle. This is a directional quantity. Spectral ...
The relative spectral flux density is also useful if we wish to compare a source's flux density at one wavelength with the same source's flux density at another wavelength; for example, if we wish to demonstrate how the Sun's spectrum peaks in the visible part of the EM spectrum, a graph of the Sun's relative spectral flux density will suffice.
Its frequency is thus the Lyman-alpha hydrogen frequency, increased by a factor of (Z − 1) 2. This formula of f = c / λ = (Lyman-alpha frequency) ⋅ ( Z − 1) 2 is historically known as Moseley's law (having added a factor c to convert wavelength to frequency), and can be used to predict wavelengths of the K α (K-alpha) X-ray spectral ...
For example, a wavenumber in inverse centimeters can be converted to a frequency expressed in the unit gigahertz by multiplying by 29.979 2458 cm/ns (the speed of light, in centimeters per nanosecond); [5] conversely, an electromagnetic wave at 29.9792458 GHz has a wavelength of 1 cm in free space.
The period (symbol T) is the interval of time between events, so the period is the reciprocal of the frequency: T = 1/f. [2] Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals , radio waves, and light.
Logarithmic measure of the number of available states of a system J/K L 2 M T −2 Θ −1: extensive, scalar Force: F →: Transfer of momentum per unit time newton (N = kg⋅m⋅s −2) L M T −2: extensive, vector Frequency: f: Number of (periodic) occurrences per unit time hertz (Hz = s −1) T −1: scalar Half-life: t 1/2