Acoustics and Sound Waves

Auditory nerve helps to carry impulses of soundwaves to the brain and thus, we hear sounds.

Sound needs a medium to travel. It cannot travel through vaccum.

Vibration of vocal cords helps to produce sound.

This value is in the audible frequency range of man.

It is the loss of energy as the signal propogates outward.

Signals tend to spread as they travel, with the amount of spreading dependent on the frequency.

Frequency is the number of oscillations per second. So, 80/4 = 20. Thus, the answer is 20 Hz.

Loudness is determined by amplitude of vibration of sound.

This is the range of audible frequency of sound for the human ear.

Decibel is the unit to measure loudness of sound.

Speed of sound is maximum in solids, and least in gases.

 For industrial area 75 and 70, commercial area 66 and 55, residential area 55 and 45, silence zone 50 and 40, silence zone includes institutional area, hospital, religious placesand specially marked as silence zone.

 Reference pressure used as $20 \mu Pa \backsimeq 106{-12}Wb/m^2$ or 1 dB minimum level of sound pressure which a healthy human earcan detect.

$v=f\lambda$
$\lambda=\dfrac{340}{1360}=\dfrac{1}{4}=0.25m$
$=25cm$
As the end is a node, shortest distance at which antinode is formed is $\dfrac{\lambda}{4}=6.25cm$