05] Assume a digital communication system with the following specifications: Pbe=0.05, (n, k) block coding with n=20 and k-bit in every message, and the block code can correct maximum of 3 bits in every received dataword. Find the following: (a) The average number of errors in every transmitted codeword. (b) The number of packets received in error from 20000 transmitted packets. [2 marks]

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]