19-6 Standing longitudinal waves Fig 19-7 2L We assume a train of n=1,2,3. sine waves travels down K a tube Fig19-7) open end 1 If the end is open. the wave at the end will behave as a pressure node(波节) close end 2) If the end is closed,a pressure antinode(波腹) 4L will form at the end 々,n=1,3,5 See动画库\波动与光学夹\2-16纵驻波We assume a train of sine waves travels down a tube( Fig19-7). 1) If the end is open, the wave at the end will behave as a pressure node (波节); 2) If the end is closed, a pressure antinode (波腹) will form at the end. (a) (b) (c) (d) close end open end Fig 19-7 19-6* Standing longitudinal waves n L n 2  = , n=1,2,3… n L n 4  = , n=1,3,5... See动画库\波动与光学夹\2-16纵驻波