The electromagnetic spectrum encompasses a wide range of frequencies, from extremely low frequencies to extremely high frequencies. The highest and lowest frequencies in the electromagnetic spectrum are as follows:
Highest Frequency: At the highest end of the spectrum, we have gamma rays. Gamma rays have the shortest wavelengths and the highest frequencies among all electromagnetic waves. Their frequencies can range from around 10^19 hertz (Hz) or higher. Gamma rays are generated by various high-energy phenomena such as nuclear reactions, radioactive decay, and some types of astronomical events.
Lowest Frequency: At the lowest end of the spectrum, we have extremely low frequency (ELF) waves. ELF waves have the longest wavelengths and the lowest frequencies. The lower frequency limit of ELF waves is generally considered to be around 3 Hz. These waves are primarily generated by natural sources such as lightning strikes and certain types of geophysical activity.
It's worth noting that the electromagnetic spectrum consists of several other types of waves, progressing from highest to lowest frequencies as follows: gamma rays, X-rays, ultraviolet (UV) rays, visible light, infrared (IR) radiation, microwaves, and radio waves. Each of these types of waves has its own distinct range of frequencies and applications.