What is another word for extremely low frequency?
Pronunciation: [ɛkstɹˈiːmli lˈə͡ʊ fɹˈiːkwənsi] (IPA) 
Extremely low frequency (ELF) refers to electromagnetic waves with very low frequencies, typically in the range of 3 to 30 Hz. However, there are several synonyms that can be used to describe this type of frequency. These include:
1. Very low frequency (VLF): This term is often used interchangeably with ELF and refers to electromagnetic waves with frequencies ranging from 3 to 30 kHz.
2. Sub-audible frequency: This term describes frequencies that are below the range of human hearing, which typically starts around 20 Hz.
3. Super low frequency (SLF): This term refers to frequencies that are even lower than ELF, typically in the range of 30 to 300 Hz.
All of these synonyms essentially refer to the same type of electromagnetic waves with very low frequencies.
