The speed of sound is greatest in
- A. air
- B. water
- C. steel
- D. vacuum
Explanation
Sound travels fastest in solids because their particles are closely bound and pass on a disturbance quickly, giving about 5000 m per second in steel against 1500 in water and 340 in air. It cannot travel through a vacuum at all, since it needs a material medium. Light behaves in exactly the opposite way, travelling fastest in a vacuum.