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After reading this section you will be able to do the following:

  • Explain what the electromagnetic spectrum is and how scientists use it.

So far we have learned about the atom, the phenomenon of radioactivity, and we have looked at both nuclear reactions and X-ray generation. We already know that X- and gamma rays differ only in their source of origin or how they are generated. There are, however, very distinct characteristics associated with these energy forms. Two key points to remember about the characteristics of radiation are that X- and gamma rays are not bits of matter, they are electromagnetic wave forms possessing no charge and no mass, and they can be characterized by frequency, wavelength, and velocity. Let's take a closer look at the characteristics of these wave forms so that we may better understand the nature of them.

What are Electromagnetic waves?

X- and gamma rays are part of what scientists refer to as the electromagnetic spectrum. They are waveforms that are part of a family in which some of the relatives are very familiar to us, such as light rays, infrared heat rays, and radio waves. However, X- and gamma rays cannot been seen, felt, or heard. In other words, our normal senses cannot detect them. Since X- and gamma rays have no mass and no electrical charge, they are not influenced by electrical and magnetic fields and will travel in straight lines. Continued research over the years since Roentgen’s discovery indicated that the radiation possesses a dual character. Acting somewhat like a particle at times and like a wave at other times. The name that has been given to the small "packets" of energy with these characteristics is "photon." It is said that the radiation photon is a wave that is both electric and magnetic in nature. Electromagnetic radiation has also been described in terms of a stream of photons (massless particles) each traveling in a wave-like pattern and moving at the speed of light.

This diagram shows the electromagnetic spectrum. Notice the changes in wavelengths of the various wave forms.

Every point across the spectrum represents a wave form of differing wavelength. It should be noted that the lines between the groupings are not precise, and that each group phases into the next.

Wave forms may be graphically represented as following:

Take the following links to learn more!


  1. Radiation is an electromagnetic wave that has no charge and no mass.
  2. X-rays and gamma-rays can be characterized by frequency, wavelength, and energy.