The initial section of the transmission line for a signal from a telephone exchange is illustrated in the figure below.
At the exchange, the input signal to the transmission line has a power of 
. After the signal has travelled a distance of 
along the transmission line, the power of the signal is 
. The signal is then amplified.
Calculate the attenuation per unit length, in 
, in the transmission line.
The gain of the amplifier is 
. Calculate the power of the signal at the output of the amplifier.
.
.
