A person can hear an approaching train when he presses his ear to the ...
The velocity of sound in solids (railway tracks) is faster than that in air.
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A person can hear an approaching train when he presses his ear to the ...
Explanation:
When a train approaches, it creates vibrations that travel through the railway tracks. These vibrations are transferred to the ground and surrounding structures, including the air. The vibrations in the air are what allow us to hear the train approaching. However, the speed at which sound travels through different mediums varies.
1. The Speed of Sound:
The speed of sound is the distance traveled per unit time by a sound wave as it propagates through a medium. It is dependent on the properties of the medium through which it is traveling. In general, sound travels faster through solids compared to liquids and gases.
2. Vibrations in Solids:
When the train approaches, it creates vibrations in the railway tracks. These vibrations travel through the solid material of the tracks, which is a much denser medium compared to air. As a result, the speed of sound in solids is higher than in air.
3. Hearing Ability:
The human ear is capable of perceiving sound waves within a certain range of frequencies. When the train approaches, the vibrations in the air that reach the person's ear are converted into electrical signals by the ear's mechanisms. These electrical signals are then processed by the brain, allowing us to perceive the sound of the approaching train.
4. Pressing Ear to Railway Track:
By pressing his ear to the railway track, the person is directly exposing his ear to the vibrations in the solid tracks. This allows the vibrations to reach his ear faster compared to someone who is simply standing on the tracks. The direct contact with the solid track bypasses the slower speed of sound in air, resulting in the person being able to hear the approaching train sooner.
In summary, the reason a person can hear an approaching train faster when pressing their ear to the railway track is because the speed of sound in solids is higher than in air. By directly exposing their ear to the vibrations in the solid tracks, the person bypasses the slower speed of sound in air, allowing them to perceive the sound of the approaching train sooner.
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