Question

Compare approximately the speed of sound in air, water and steel.
A. $17:4:1$
B. $4:1:17$
C. $4:17:1$
D. $1:4:17$

Answer 1

Hint: Sound is a mechanical wave. It travels as a disturbance in the medium propagated by the particles in the medium. Hence, the closer the particles in the medium will be, the faster will be the speed of sound in that medium. The speed of sound in gases is the slowest and that in solids is the fastest.

Complete step by step answer:
Sound is a mechanical wave. What this essentially means is that the wave travels with the help of the particles in the medium. A mechanical wave cannot travel in absence of a medium (in vacuum).
The mechanism of propagation of sound is that it produces continuous places of compression (higher density of particles in the medium) and rarefaction (lower density of particles in the medium). These compressions and rarefactions keep on oscillating with the frequency of the wave and therefore, keeps on propagating the disturbance through the medium.
Hence, it is quite intuitive that the speed by which the wave will propagate will depend on how nearby the particles are to each other, so that the disturbance can be transferred easily from particle to particle. The closer the particles in a medium are to each other, faster will be the speed of sound in that medium.
Since, molecules are very closely packed in solids, less closer in liquids and least closely packed in gases, the speed of sound is greatest in solids and least in gases.
Hence, sound travels fastest in steel (a solid), slower in water (a liquid) and slowest in air (gas).
The speed of sound in steel is about $5800m/s$.
The speed of sound in water is about $1480m/s$
The speed of sound in air is about $340m/s$.
Hence, ratio of speed of sound in air: water: steel will be $340:1480:5800=1:4.35:17.06$
The answer closest to this is D) $1:4:17$.

Note: Even if students did not know the exact values of the speeds of sound in the three media, they could have found out the correct option by examining the options closely and using the concept that sound travels slowest in gases and fastest in solids. Using this concept, the only option that would satisfy this criterion would be the option D) and hence students could have marked this without calculations.
However, sometimes there are more than two options that fit the criterion. Then there would be no other choice but to plug in the exact values for the speeds and do the required calculation.