Question

Sound travels the fastest through vacuum. State true or false
$(a)$ True
$(b)$ False

Answer 1

Hint: The concept says that sound waves travel through the air or water as a longitudinal wave and when sound waves propagate through solids it shows the property of transverse waves. The speed of sound waves is fastest through solid, then liquid and then gas. Vacuum is simply an empty space but sound waves require a medium to travel. This will help approaching the answer.

Complete step-by-step answer:
As we know that to travel the sound waves there must be some particles present for the propagation of these sound waves.
Now as we know that in a vacuum there are no such particles and in the vacuum the gaseous pressure is much less than the atmospheric pressure.
As there are no such particles present in the vacuum (as vacuum is an empty space) the speed of sound waves in the vacuum is zero.
Sound is a mechanical wave which requires a medium for the propagation of the sound waves, so the sound cannot travel in vacuum as in vacuum there is no medium only an empty space.
So, the vacuum speed of sound is zero.
Speed of sound is maximum in solids and minimum in gases but it is zero in vacuum.
The increasing order of speed of sound is given below:

Solid > liquid > gas.

Speed of sound in solid is approximately 6000 m/s.
Speed of sound in liquid (i.e. water) is approximately 1402 m/s.
Speed of sound in gas (i.e. hydrogen) is approximately 1270 m/s.
So the speed of sound in vacuum is zero.
Hence the given statement is false.

Hence option (B) is the correct answer.

Note: Dependence of medium for travel of sound waves leads to a very important phenomena, the internal combustion of gases in sun produces very large explosions which are very noisy too, however these noises of explosion can’t be heard as vacuum separates the earth and the sun, thus these sound waves can never be transported through the vacuum medium.