Question

Through which of the following media does sound travel the fastest?
(A) Cold water
(B) Warm water
(C) Cold air
(D) Steel

Answer 1

Hint:Find out which of the following medium is denser. Compare the densities of cold water, warm water, cold air and steel.

Complete step by step answer:
Sound speed is the distance travelled by a sound wave, as it propagates across an elastic medium, per unit of time. In an ideal gas, the speed of sound depends only on its temperature and its composition. Velocity in ordinary air has a poor dependency on frequency and pressure, somewhat deviating from desirable behaviour. The three aspects influencing the speed of the sound wave are temperature, density and rigidity of the medium in which the wave passes. Based on ambient conditions, the velocity varies; the temperature is the most significant component. Humidity has no effect on sound velocity, nor does air pressure on its own. In an ideal gas approximation, the air pressure has no effect whatsoever. The speed of sound is dependent on the material's elasticity. Steel has the highest elasticity in the given choice, so sound can pass through steel the fastest.
Hence, the correct option is (D).

Additional information:
The sound velocity is not exactly the same. Recall the sound is a kinetic energy signal transferred from molecule to molecule. The closest the molecules are to each other, the less time it takes for them to transmit the sound to each other, the tighter their bonds, and the further the sound can pass. It is simpler for sound waves to travel through solids than through liquids since the molecules are attached to each other and fused more tightly through solids. Similarly, travelling through gases is more difficult for hearing than going through liquids, since gaseous molecules are further apart. Sound speeds are quicker in solid materials and slower in liquids or gases.

Note: In this question you are asked to find in which medium, the speed of sound is fastest. It is worth remembering that concept of elasticity comes into play. Note that the density of steel is more than that of any medium mentioned in the options. Higher the density of the material, higher is the speed of the sound.