Longitudinal waves have a. crests and troughs b. troughs and rarefactions c. crests and compressions d. compressions and rarefactions

Imagine that the rightward current flows in the rod for a short time. as a result, what will the net charge on the right and left ends of the rod become? left end negative and right end positive left end negative and right end negative left end negative and right end nearly neutral left end nearly neutral and right end positive both ends nearly neutral