Question

Velocity of sound is maximum in
$A)$Iron
$B)$Mercury
$C)$Water
$D)$Air

Answer 1

We must know the fact that the speed of sound depends only on the nature of the medium through which it is travelling. Specifically, it depends upon the elasticity and density of the medium. Also, another factor affecting the speed of sound in a medium is temperature. So, we must keep this all in mind to choose the right option.

Complete answer: We commonly refer to the speed of sound as the speed of sound waves in air. But we must know that the speed of sound waves varies from medium to medium.
If we examine the velocity of sound waves in different states of matter, we can observe that sound waves are basically slower in gas medium, but it is faster than the gaseous medium when moving through liquids but yet slower than when a sound wave is moving through a solid material. So, we can understand that sound waves travel faster in solids. This is due to the alignment/distance between the atoms inside materials. Sound waves travel by compression and rarefaction of particles present in a medium.

Now, if we look at velocity of sound waves given through different materials,
Sound waves have a velocity of $343m/s$ in air at $20{}^\circ C$. In water, sound waves travel with a velocity of $1480m/s$ and if we take velocity of sound wave through aluminium, it moves with velocity of $6320m/s$.
So, we can conclude that sound waves move faster in solid materials. If we look at the options given, iron is the only solid. So, the correct answer is “Option A”.

Note:
We must be aware that speed of sound is also defined as the speed at which the smallest disturbance travels through a medium. It depends on the packing of atoms in a material. The more closer the atoms, speed of sound increases.