Question

Which of the following correctly show the way sound vibrations travel?
(A)

(B)

(C)

(D)

Answer 1

Hint: Sound vibrations in air are formed when air molecules oscillate or vibrate and move at a direction away from the vibrating source. Sound vibrations travel in any material medium in the form of sound waves which are mechanical in nature.

Complete answer:
Sound waves in any material medium are mechanical waves. Sound waves travel in the form of longitudinal vibrations. Longitudinal vibrations have a distinctive property that they move in all directions. Longitudinal waves travel in any material medium in the form of a series of compressions and rarefactions.
Thus, sound waves travel outwards in all directions in the form of a series of compressions and rarefactions of the particles of the medium from the source. As the longitudinal sound waves travel, the energy they contain becomes dissipated or damped and as a result of which the intensity of the sound becomes weaker the farther it is from the source.
Thus, we can say that the shape of a longitudinal sound wave vibration with no obstacles in its direction of propagation would be spherical under approximation.
Since only the figure given in option (C) properly matches our description of a longitudinal sound wave vibration.

We can say that option (C) is the correct answer to this question.

Note: If we consider a sound wave to be moving at a direction from left to right through a medium of air, then in this condition the particles of the medium of air will be displaced at directions both rightward and leftward as the energy of the sound wave passes through it.
The motion of the particles of the medium is both, parallel and anti-parallel to the direction of the energy transport. This is what characterizes sound waves travelling in any material medium such as air as longitudinal waves.