Extremely low frequency

{
  "id": "MLC-T-IND-002133",
  "term": "Extremely low frequency",
  "field": "Industrial and trades",
  "definition": "The portion of the electromagnetic spectrum with frequencies ranging from 3 to 30 hertz (Hz). These waves have very long wavelengths, extending thousands of kilometers, allowing them to penetrate water and earth. Extremely low frequency signals are primarily used for specialized communication with submarines and for geophysical research.",
  "subject": "Electrical engineering",
  "translations": {
    "de": "ELF",
    "es": "frecuencia extremadamente baja",
    "fr": "extrêmement basse fréquence"
  },
  "url": "https://mlchart.com/terminology/industrial/extremely-low-frequency/"
}