Measuring Sound Intensity Decibel Created for CVCA Physics

Measuring Sound Intensity (Decibel) Created for CVCA Physics By Dick Heckathorn 25 April 2 K + 5

Definition The faintest sound which the typical human ear can detect has an intensity of

A sound which will displace particles of air by a mere one-billionth of a centimeter has an intensity of Known as the threshold of hearing

Decibel (d. B) Scale This scale is a logarithmic scale used for measuring the intensity of sound. The threshold of hearing is assigned a sound level of zero decibels. Intensity (W/m 2) Intensity (d. B) 1 x 10 -12 0 1 x 10 -11 10 1 x 10 -10 20

Decibel (d. B) Scale Intensity (W/m 2) (d. B) 1 x 10 -12 0 threshold of hearing 1 x 10 -11 10 normal breathing 1 x 10 -10 20 average whisper (2 m) 1 x 10 -9 30 empty theatre 1 x 10 -8 40 residential area-night 1 x 10 -7 50 quiet restaurant 1 x 10 -6 60 2 -person conversation 1 x 10 -5 70 busy street traffic 1 x 10 -4 80 vacuum cleaner

Decibel (d. B) Scale Intensity (W/m 2) (d. B) 1 x 10 -3 90 loud stereo 1 x 10 -2 100 concert hall 13 th row 1 x 10 -1 110 pneumatic chisel 1 120 max level rock group 10 130 threshold of pain 1 x 102 140 military jet taking off 1 x 103 150 wind tunnel 1 x 104 160 instant braking ear drum

Decibel (d. B) Scale With each increase in intensity of 10 -d. B, the intensity of sound increases in intensity by a factor of ten. Thus if the intensity of sound is increased by 30 decibels, the intensity is 1000 times greater.

Decibel (d. B) Scale The earplugs provided state that they reduce the sound level by 31 decibels. Thus the intensity of sound is reduced by a factor of 1259.

Sound in the Workplace The earplugs provided state that they reduce the sound level by 31 decibels. Thus the intensity of sound is reduced by a factor of 1259.