Question

How does sound from a sound producing body travel through air to reach our ears?
(A) through crest and trough
(B) through compression and rarefaction
(C) both
(D) none

Answer 1

Hint: We know that the sound-producing body generates energy in the form the vibration, and the intensity of vibration varies according to the sound produced. The vibration travels in the form of waves through the air to reach our ears. By using the behaviour, properties, and condition of the vibration, we can tell how it travels in the air.

Complete step by step answer:
The generation of sound occurs when the body vibrates. The matter like air, water present near the body also vibrates because the vibration propagates from one place to another place. For example, if the school bell ringing occurs, the part of the bell vibrates, and due to this vibration, the generation of sound occurs. The bell's fast vibration results in loud sound because more energy is associated with the fast vibration. The sound can travel in all three states of the matter.The vibration generated from the body travels in the form of waves, and the propagation of vibration in the air is known as travelling longitudinal waves. The sound waves travel due to the pressure difference present in the air, so the sound waves come under high and low pressure. The high-pressure area in which wave particles come close to each other is known as compression, and the low-pressure area, where the particles of the waves are away from each other, is known as rarefaction. Due to compression and rarefaction, the sound wave travels through the air.
Therefore, the sound from a sound producing body travels through air to reach our ears through compression and rarefaction and the option (B) is correct.

Note:Do not create confusion about the compression and rarefaction because sometimes students understand both things oppositely. So keep things simple that the high pressure tends to compress the sound waves, and due to this reason, the high-pressure area is known as compression and vice versa.