Yes, there are electromagnetic waves below 3 kHz. Electromagnetic waves span a broad range of frequencies, from extremely low frequencies (ELF) to gamma rays. The frequency range below 3 kHz falls within the category of extremely low frequencies (ELF).
ELF waves have frequencies ranging from about 3 Hz to 3 kHz. These waves have longer wavelengths and lower energies compared to higher frequency waves like radio waves, microwaves, and visible light. ELF waves are commonly used for communication with submarines, as they can penetrate water more effectively than higher frequency waves.
Examples of sources that produce ELF waves include power transmission lines, which emit electromagnetic fields at 50 or 60 Hz, depending on the region. Natural phenomena like lightning also generate electromagnetic waves at ELF frequencies.
It's worth noting that ELF waves are generally not used for everyday communication or broadcasting purposes due to their limited bandwidth and challenges associated with generating and detecting such low-frequency signals. However, they do play a role in certain specialized applications and scientific research.