Electromagnetic radiation comes in a large range of frequencies and wavelengths. The range is referred to as "the electromagnetic spectrum".  To give a few examples:  in the range of 104 to 1012 Hz the electromagnetic spectrum has a portion called radio waves. From 1012 to 1014 is the range called infrared.  From 1017 to 1019 we have what are called the X-rays.  Microwaves are part of the radio wave portion in the shorter wavelength portion of the radio waves.

Infrared radiation consists of the range of frequencies that can make molecules of most substances vibrate internally. An increase in internal vibration is measured by an increase in temperature.

                                          The Electromagnetic Spectrum

                                                   Frequency (cycles/s)
104      105     106      107    108      109    1010    1011    1012 1013    1014   1015   1016  1017    1018 1019
  |         |         |         |         |         |         |         |         |        |         |         |         |        |         |         |
  |                        Radio waves                                  |   Infrared   |   |    Ultraviolet    | X-rays  |
  |     Long     |  Short   |   TV  |       Microwaves       |                    ^                                            ^
  |    waves     |  waves  |          |                     _           |                    |                                              |
                                                                                            Visible Light                     Gamma rays

Of all these radiations, your eyes are able to sense only a very narrow band ranging from about 400 nm (violet)  to 700 nm (red).  This corresponds to 7.5 X 1014 to 4.3 X1014 Hz.   This narrow band is called the visible spectrum and consists of all the colours that can be seen from red through orange, yellow, green, blue, indigo and violet. White light is composed of all these colours in equal amounts.  Red light borders on the left with infrared (under red) and violet borders on the right with ultraviolet (above violet).

Following the rules in the last worksheet the radio waves with a frequency of 104 Hz would have the longest wavelength of 30,000 metres. As we go to the right the wavelengths get smaller and smaller. Microwaves with a frequency of 1010 Hz have a wavelength of 3 mm. X-rays with a frequency of 1017 Hz have wavelengths of 3 nm.  At the very end of the scale we have gamma and cosmic rays which have a frequency of 1019 Hz which means a wavelength of only 0.03 nm.
             Go to The Electromagnetic Spectrum Worksheet