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Physics Chapter 26
Sound
Question | Answer |
---|---|
Sound wave are produced by what? | the vibrations of material objects. |
A disturbance in the form of a longitudinal wave travels away from the vibrating souce. | correct |
High-pitched sounds ae produced by sources vibrating at high frequency, while low-pitched sounds are reproduced by low frequency sources. | correct. |
Sound waves constist of what? | traveling pulses of high pressure zones, or compressions, altenating wth pulses of low-pressure zones, or rarefactions. |
Sound can travel through: | gases, liquids, and solids |
Soun cannot travel through: | a vacuum. |
Sound travels fastest through: | very elastic materials, such as steel. |
Every object vibrates at its own set of natural frequencies. | correct. |
When an object such as a sounding board is forced to vibrate by a sound source, the sound becomes louder. | correct. |
When an object is forced to vibrate at one of its own natural frequencies, resonance occurs and the sound becomes much louder. | correct. |
Like any waves, two sound waves can exhibit interference and make sound louder and softer. | correct. |
Rapid changes in loudness, known as beats, occur wen two tones very close in frequency are heard at the same time. | correct. |
All sounds are produced by: | the vibrations of material objects. |
How does sound work? | The orginal vibration stimulates the vibation of something larger or more massive. This vibrating material then sends a disturbance through a surrounding medium, usually air, in the form of longitudinal waves. oridnary conditions: source Hz=soundwave Hz |
For all wave motion, it is not the medium that travels across the room, but | a PULSE that travels. |
Do solids and liquids conduct better or worse than air? | Better. Sound travels faster in liquids than in gases, and faster in solids. |
SOUND CANNOT TRAVEL IN A VACUUM. Why? | If there's nothing to compress and expand, there can be no sound. There may be vibrations, however. |
Sound is much slower than light. | correct. |
The speed of sound in a material depends on the material's elasticity, which is the ability of a material to change shape in repsonse to an applied force, and the resume its initial shape once the distorting force is removed. | correct. |
Sound travels about 15 times faster in steel than in air, and about four time faster in water than in air. | correct. |
The intensity of sound is proportional to the square of the amplitude of a sound wave. | correct. |
The unit of intesity for sound is the decibel (dB), after Alexander Graham Bell(inventor of the telephone.) | correct |
A natural frequency is one at which minimum energy is required to produce forced vibrations. It is also the frequency that requires the least amountof enery to continue this vibration. | correct |
Natural frequency depends on what? | elasticity and shape of the object |
What is resonance? | WHen the frequency of a forced vibratio on an object matches the object's natual frequency, a dramatic increase in amplitude occurs. This phenomenon is called resonance. |
What does something need to resonate? | It needs a force to pull it back to its starting position and enough energy to keep it vibrating. |
For sound, the crest of a wave correponds to a compression, and the trough of a wave corresponds to a rarefaction. | correct |
The periodic vartion in the loudness of sound is called | beats. |