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Acoustics
Properties of sound
Question | Answer |
---|---|
What is the speed of sound in air at room temperature? | 343 m/s |
What is the range of hearing for the human hearing system? | 20Hz to 20kHz |
How does sound travel in air? | By bouncing particles into other particles in the air |
Does sound travel faster in metal than in air? | Yes |
Why does sound travel faster in more dense material/medium | Because the particles or molecules are much closer together - they do not have to travel so far to hit the next particle |
Approximately, what is the wavelength of a 20Hz soundwave? | 17m |
Approximately, what is the wavelength of a 20kHz soundwave? | 17mm |
Does a high frequency sound travel faster than a low frequency sound? | No, they travel at the same speed of sound |
What is the unit of frequency? | Hertz (Hz) - this used to be known as cycles per second |
Amplitude is the measure of what? | Amplitude is the measure of how loud a sound is - high amplitude is loud but low amplitude is quiet |
Decibel is used as a measure of sound - what is the symbol for decibel? | dB |
0 dB represents what value of gain? | This represents no gain - what comes out is what goes in - it is not reduced or amplified |
The reference for dBm is what? | 1 mW |
What is the periodic time of a soundwave? | It is the time taken from the start of a cycle to the end of it - usually represented by 'T' |
What is the periodic time for a 20Hz soundwave? | 50 ms |
What is the periodic time for a 20kHz soundwave? | 50 us |