(a)[1]
Suggest why attenuation of a signal in channels of communication is normally measured on a logarithmic scale rather than a linear one.
(b(i))[1]
For a communication channel with low attenuation, the input power is $6.5\,\text{mW}$ and the attenuation per unit length is $1.8\,\text{dB km}^{-1}$. Suggest the name of this communication channel.
(b(ii))[3]
Calculate the distance over which the signal power drops to $1.5 \times 10^{-15}\,\text{W}$.