(a(i))[1]
State the meaning of attenuation.
(a(ii))[4]
The infra-red radiation is carried as a sequence of pulses. State and explain two advantages of digital transmission of information instead of analogue transmission.
(b)[2]
An optic fibre of length $36\,\text{km}$ has an input light power of $145\,\text{mW}$ and an output light power of $29\,\text{mW}$. Calculate the attenuation per unit length of the optic fibre, in $\text{dB}\,\text{km}^{-1}$.