1. The problem statement, all variables and given/known data a vibrating source makes 16 pulses every 4 seconds find the frequency 2. Relevant equations frequency=n/t pulse is half a wave 3. The attempt at a solution if we consider a pulse as half a wave then the source produces 8 waves then frequency=8/4=2 hertz but that's not the right answer according to the text book: frequency=16/4=4 Hz I'm completely confused can u explain the right answer? Thanks in advance!!