To solve this problem we must rely on the concepts related to wavelength in terms of the speed of light and frequency.
Mathematically one of the ways to express the wavelength is,
[tex]\lambda = \frac{c}{f}[/tex]
Where,
c = Speed of light [tex](3*10^8m/s)[/tex]
f = Frequency
The value of the frequency given is
f = 45Hz
Therefore replacing we can find it,
[tex]\lambda = \frac{3*10^8}{45Hz}[/tex]
[tex]\lambda = 6.6667*10^6m[/tex]
Hence the wavelength of the very low frequency electromagnetic wave is [tex]6.6667*10^6m[/tex]
