- Electromagnetic radiation comprises of oscillating electric and magnetic field components through which information transfer can occur.
- These oscillations are sinusoidal in nature and expressed in cycles per second or hertz (Hz).
- The range is of these oscillations is quite wide from as low as 1 Hz and can extend up to a large value.
- The entire range of the frequencies that the electromagnetic waves can produce is known as Electromagnetic Spectrum.
- The electromagnetic spectrum ranges from below the low frequencies which are used for radio communication to gamma radiation at the high-frequency, thereby covering wavelengths from thousands of kilometres down to a fraction of the size of an atom.
- Most of the frequencies of Electromagnetic spectrum are used for wide range of communication systems based on different applications.
- Electromagnetic waves are distinguished by three physical properties, which are frequency f, wavelength λ and photon energy E.
- The below given Table1 describes the entire frequency range of electromagnetic spectrum along with its applications.
Frequency (f) |
EM Spectral region |
Application |
30-300 Hz |
Extremely low frequency (ELF) |
Power line communication |
0.3-3 kHz |
Voice frequency (VF) |
Speech communication |
3-30 kHz |
Very low frequency (VLF) |
Submarine communication |
30-300 kHz |
Low frequency (LF) |
Marine communication |
0.3-3 MHz |
Medium frequency (MF) |
AM Broadcasting |
3-30 MHz |
High frequency (HF) |
Landline telephony |
30-300 MHz |
Very high frequency (VHF) |
TV, FM Broadcasting |
0.3-3 GHz |
Ultra high frequency (UHF) |
TV, Cellular telephony |
3-30 GHz |
Super high frequency (SHF) |
RADAR, Microwave oven |
30-300 GHz |
Extremely high frequency (EHF) |
Satellite communication, RADAR |
Table1. Electromagnetic spectrum