An optical fibre has an attenuation of 0.3 dB/km. If a laser launches an optical power level of PIN (mW) into 35 km length of this fibre, at what distances will the power have dropped to:
(a) 75%
(b) 50%
(c) 25%
(d) 12.5%
(e) 6.25%
of the input power level? Plot these points on a graph of P IN/P OUT versus distance along the fibre.