Question:
In which of the following the sound cannot travel?
ASolids
BLiquids
CGases
DVacuum
Answer:
D. Vacuum
Explanation:
Sound waves are mechanical waves, that is, they require material medium to travel. It is the movement of the medium that transmits the wave.
Since the density of solids is high and the molecules of a solid are closely packed, sound waves are quickly transmitted from one molecule to the next thus enabling it to travel faster. The speed of sound, therefore, is fastest in solids, followed by liquids (less dense than solids) and then gas (least dense).
Sound cannot travel in a vacuum as there is no material medium.