Question

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Answer 1

1)

Vibration, periodic back-and-forth motion of the particles of an elastic body or medium, commonly resulting when almost any physical system is displaced from its equilibrium condition and allowed to respond to the forces that tend to restore equilibrium.

2)

AUDIBLE SOUNDS :

The human ear can easily detect frequencies between 20 Hz and 20 kHz. Hence, sound waves with frequency ranging from 20 Hz to 20 kHz is known are audible sound. The human ear is sensitive to every minute pressure difference in the air if they are in the audible frequency range. It can detect pressure difference of less than one billionth of atmospheric pressure.

Examples of vibrating sources that produce sound in the audible range of frequencies are drums, guitar strings, tuning fork, human vocal cords and diaphragms of loudspeakers

3)

Sound waves travels through a medium such as a solid, liquid, or gas. These waves move through each of these mediums by vibrating the molecules in the matter. The molecules present in solids are packed very tightly. Liquids molecules are not packed as tightly as solids. And gases are very loosely packed. The spacing of the molecules enables sound to travel much faster through a solid than a gas. Sound travels about 4 times faster and farther in water than it does in air. This is why whales can communicate over huge distances in the oceans. Sound waves travel about 13 times faster in wood than air. They also travel faster on hotter days as the molecules bump into each other more often than when it is cold.

4) No, you cannot hear any sounds in near-empty regions of space. Sound travels through the vibration of atoms and molecules in a medium (such as air or water). In space, where there is no air, sound has no way to travel.

Astronauts have devices in their helmets which transfer the sound waves from their voices into radio waves and transmit them to the ground (or other astronauts in space). This is how a radio at home works , radio waves are often thought to be a form of sound but they are not sound waves