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  2. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    Frequencies observed in astronomy range from 2.4 × 10 23 Hz (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1 kHz). Wavelength is inversely proportional to the wave frequency, [ 1 ] so gamma rays have very short wavelengths that are fractions of the size of atoms , whereas wavelengths on the opposite ...

  3. Infrared - Wikipedia

    en.wikipedia.org/wiki/Infrared

    Infrared spectroscopy examines absorption and transmission of photons in the infrared range. [9] Infrared radiation is used in industrial, scientific, military, commercial, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected.

  4. Electromagnetic absorption by water - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_absorption...

    In the near-infrared range liquid water has absorption bands around 1950 nm (5128 cm −1), 1450 nm (6896 cm −1), 1200 nm (8333 cm −1) and 970 nm, (10300 cm −1). [ 19 ] [ 20 ] [ 15 ] The regions between these bands can be used in near-infrared spectroscopy to measure the spectra of aqueous solutions, with the advantage that glass is ...

  5. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    Thus, higher frequency photons have more energy. For example, a 10 20 Hz gamma ray photon has 10 19 times the energy of a 10 1 Hz extremely low frequency radio wave photon. The effects of EMR upon chemical compounds and biological organisms depend both upon the radiation's power and its frequency.

  6. Visible spectrum - Wikipedia

    en.wikipedia.org/wiki/Visible_spectrum

    In terms of frequency, this corresponds to a band in the vicinity of 400–790 terahertz. These boundaries are not sharply defined and may vary per individual. [4] Under optimal conditions, these limits of human perception can extend to 310 nm (ultraviolet) and 1100 nm (near infrared). [5] [6] [7]

  7. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque, until it becomes transparent again in the near-infrared and optical window frequency ranges. These ITU radio bands are defined in the ITU Radio Regulations. Article 2, provision No. 2.1 states that "the radio ...

  8. Near-infrared spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Near-infrared_spectroscopy

    Near-IR absorption spectrum of dichloromethane showing complicated overlapping overtones of mid IR absorption features.. Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from 780 nm to 2500 nm). [1]

  9. Far infrared - Wikipedia

    en.wikipedia.org/wiki/Far_infrared

    Far infrared (FIR) or long wave refers to a specific range within the infrared spectrum of electromagnetic radiation. It encompasses radiation with wavelengths ranging from 15 μm (micrometers) to 1 mm, which corresponds to a frequency range of approximately 20 THz to 300 GHz. This places far infrared radiation within the CIE IR-B and IR-C ...