Ascientist heard a flexible container full of neon gas. what will be likely to happen to the container as the gas absorbed heat

As the gas absorbs heat, the sounds he hears become softer.  This is because the pressure of the neon gas inside the container increases when the gas gets warmer, the walls of the container become tighter and stiffer, and it's harder for them to vibrate.

a displacement distance is size of displ

seeing the graph would