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  2. List of refractive indices - Wikipedia

    en.wikipedia.org/wiki/List_of_refractive_indices

    1 (by definition) Air at STP: 1.000273 [citation needed] Gases at 0 °C and 1 atm Air: 589.29: 1.000293 [1] ... Luxpop: Index of refraction values and photonics ...

  3. Retardation factor - Wikipedia

    en.wikipedia.org/wiki/Retardation_factor

    An R F value will always be in the range 0 to 1; if the substance moves, it can only move in the direction of the solvent flow, and cannot move faster than the solvent. For example, if particular substance in an unknown mixture travels 2.5 cm and the solvent front travels 5.0 cm, the retardation factor would be 0.50.

  4. Refractive index - Wikipedia

    en.wikipedia.org/wiki/Refractive_index

    [1]: 236 The birefringence of the material is the difference between these indices of refraction, Δn = n e − n o. [1]: 237 Light propagating in the direction of the optical axis will not be affected by the birefringence since the refractive index will be n o independent of polarization. For other propagation directions the light will split ...

  5. Attenuation coefficient - Wikipedia

    en.wikipedia.org/wiki/Attenuation_coefficient

    Most commonly, the quantity measures the exponential decay of intensity, that is, the value of downward e-folding distance of the original intensity as the energy of the intensity passes through a unit (e.g. one meter) thickness of material, so that an attenuation coefficient of 1 m −1 means that after passing through 1 metre, the radiation ...

  6. Relative permittivity - Wikipedia

    en.wikipedia.org/wiki/Relative_permittivity

    In the high-frequency region, which extends from radio frequencies to the far infrared and terahertz region, the plasma frequency of the electron gas is much greater than the electromagnetic propagation frequency, so the refractive index n of a metal is very nearly a purely imaginary number. In the low frequency regime, the effective relative ...

  7. Radio frequency - Wikipedia

    en.wikipedia.org/wiki/Radio_frequency

    Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency [1] range from around 20 kHz to around 300 GHz.

  8. Signal-to-noise ratio - Wikipedia

    en.wikipedia.org/wiki/Signal-to-noise_ratio

    A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR is an important parameter that affects the performance and quality of systems that process or transmit signals, such as communication systems, audio systems, radar systems, imaging systems, and data acquisition systems. A high SNR means that the signal is clear ...

  9. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    Equivalently, , the distance that a radio wave travels in vacuum in one second, is 299,792,458 meters (983,571,056 ft), which is the wavelength of a 1 hertz radio signal. A 1 megahertz radio wave (mid-AM band) has a wavelength of 299.79 meters (983.6 ft).