A reactive muffler is to be designed to produce a transmission loss of 20 dB at 150 Hz. The inlet and outlet and outlet pipes are 60 mm in diameter and the average temperature of the exhaust gas is 100C. (a) Show that the transmission loss of the reactive muffler is given by     2 1 2 4 TL m m kL    10log 1 1 sin     where m is the area ratio of the expansion chamber to the inlet/outlet duct. (b) Determine the size of the expansion chamber – the cross-sectional area A2 and the length L. You may take the speed of sound at 20C as 343 m s-1