question_answer 11)

  A 1 KW signal is transmitted using a communication channel which provides attenuation at the rate of - 2 dB per km. If the communication channel has a total length of 5 km, the power of the signal received is [gain in dB = 10 log] (a) 900W                              (b) 100W (c) 990W                              (d) 1010W

Answer:

  (b) Here, Pi = 1 kW = 1000 watt, length of path = 5 km; P0 =?                                     Loss of power at a distance of 5 km =2x5=10  dB. As gaining =             or Or