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  • In this nugget we will learn about the electromagnetic spectrum.

  • The spectrum of electromagnetic radiation is extremely wide.

  • It ranges from the wavelengths of long-wave radio transmissions

  • (up to 2000 metres), via short-wave AM and FM radio

  • (wavelengths from 100 meter to a few meters),

  • microwave, radar transmission waves and transmission from similar objects.

  • The wavelength of heat or radiation lies at wavelengths of less than one thousandth of a millimeter.

  • Finally, we have radiation with a wavelength between

  • 780 and 380 nanometers (millionth of a millimeter,

  • or 10 to the power minus 9 meters),

  • which is the visible part of the electromagnetic spectrum

  • and therefore referred to as light.

  • Different wavelengths in the visible part of the spectrum result in different colour impressions as wavelength decreases.

  • At lower wavelengths we have

  • the ultraviolet region.

  • The longer wavelengths in this UV range are

  • part of the radiation we receive from the sun and

  • are considered beneficial (UVA).

  • They result in tanning of the skin.

  • Shorter-wave ultraviolet radiation (UVB),

  • on the other hand, is potentially

  • dangerous to the skin and eyes,

  • although we need it in small quantities

  • because UVB produces vitamin D.

  • The shortest ultraviolet radiations (UVC) are

  • used as disinfectants

  • since they kill bacteria.

  • Still shorter wavelengths bring us first to X-rays,

  • which penetrate the body,

  • and then to the highly-dangerous gamma-rays,

  • emitted as a result of nuclear decomposition.

  • Finally we come to the Cosmic rays,

  • which result from collisions between extremely-fast-moving particles

  • travelling from the outposts of the universe.

  • Cosmic rays have wavelengths down to 10 to the power minus 18 meters.

  • In this nugget, we described the spectrum of the electromagnetic radiation.

  • A spectrum is a range of wavelengths

  • which consists of frequencies that can vary

  • from the invisible radio and gamma waves to the visible light spectrum.

  • Thank you.

In this nugget we will learn about the electromagnetic spectrum.


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B1 中級

電磁頻譜 (The Electromagnetic Spectrum)

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    VoiceTube 發佈於 2021 年 01 月 14 日