Some of the properties which are common to all electromagnetic waves are amplitude, a characteristic frequency and wavelength, and the ability to travel through a vacuum at the same speed, which is commonly referred to as the speed of light. All electromagnetic waves also propagate electrical and magnetic fields in a direction which is perpendicular to their direction of energy flow. The electrical and magnetic fields are in phase and at 90-degree angles to each other.
Amplitude refers to the distance, or height, from the middle of an electromagnetic wave to its maximum displacement. This reflects a magnitude of oscillation, and it is also a measurement of the amount of energy contained in an electromagnetic wave.
The distance covered by one complete oscillation cycle of an electromagnetic wave is referred to as its wavelength. This is an individual characteristic which is unique to the type of electromagnetic radiation. Wavelength is usually measured in nanometers, and it represents the distance between two adjacent peaks in a wave.
Frequency refers to the number of complete wave oscillations occurring over a given period of time or passing by a specific point in a second. Frequency and wavelength are interrelated and proportional. Shorter wavelengths reflect higher frequencies and longer wavelengths are found in the lower frequency electromagnetic waves. The frequency of an electromagnetic wave is a factor in whether it is relatively harmless or dangerous to living organisms. Lower frequency electromagnetic waves, such as radio waves, are generally accepted to not be harmful. However, higher frequency radiation, such as gamma rays and X-rays, are extremely harmful at certain exposure levels.