(WVS) Electromagnetic Spectrum Lesson

Electromagnetic Spectrum

EM radiation is classified into types according to the frequency, wavelength, and amount of energy of the wave: these types include, in order of increasing frequency, radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Electromagnetic Spectrum Links to an external site.

Different frequencies of EM radiation have different degrees of penetration. For example, if we take the human body as the object, visible light is reflected off the surface of the human body, ultra-violet light (from sunlight) damages the skin, but X-rays are able to penetrate the skin and bone and allow for pictures of the inside of the human body to be taken.

If we compare the energy of visible light to the energy of X-rays, we find that X-rays have a much higher frequency. Usually, electromagnetic radiation with higher frequency (energy) has a higher degree of penetration than those with low frequency.  Certain kinds of electromagnetic radiation such as ultraviolet radiation, X-rays, and gamma rays are very dangerous. Excessive exposure to radiation, including sunlight, X-rays, and all nuclear radiation, can cause the destruction of biological tissue. Luckily, the Earth's atmosphere protects us and other living beings on Earth from most of the harmful EM radiation.

Electromagnetic Comparision Links to an external site.

For a summary review of this lesson, please watch the following video:

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