Calculate the wavelength of Radio 4 which broadcasts on a frequency of 198 kHz.

Wavelength $(\lambda )=$ Speed of Light $(c)/$ Frequency $(f)$
The speed of light (c) is approximately $3\times 10^8$ meters per second.
Given:
Frequency $(f)=198\mathrm{kHz}(198,000\mathrm{Hz})$
Converting the frequency to $\mathrm{Hz}$ :
$198\mathrm{kHz}=198,000\mathrm{Hz}$
Plugging in the values:
Wavelength $(\lambda )=\left(3\times 10^8\mathrm{m}/\mathrm{s}\right)/(198,000\mathrm{Hz})$
Simplifying the equation:
Wavelength $(\lambda )\approx 1515.15$ meters
Therefore, the wavelength of Radio 4, which broadcasts at a frequency of $198\mathrm{kHz}$, is approximately 1515.15 meters.