Sound travels at a speed of 330ms-1 in air , 1500ms-1 in x and cannot be transmitted through Y. which one of the following is correct about the physical properties of X and Y?
X contains on material medium and Y is less dense than air
X contains no material medium and Y is less dense than air
X is denser than air and Y contains no material medium
X is less dense than air Y contains on material medium
