CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

The loudness level at a distance R from a long linear source of sound found to be 40dB. At this point, the amplitude of oscillations of air molecules is 0.01 cm. Then find the loudness level(in dB) at a point located at a distance '10R' from the source. 


Solution

Loudness of the sound        $$L = 10  log_{10} \dfrac{I}{I_o} $$   where  $$I = \dfrac{I_o}{r^2}$$

Thus      $$L = 20  log_{10} \dfrac{1}{r} $$ 

$$\implies $$   $$L_2 - L_1 = 20  log_{10} \dfrac{r_1}{r_2} $$ 

Given :   $$r_1 = R                 r_2 =  10  R                L_1 = 40  dB$$

   $$L_2 - 40 = 20  log_{10} \dfrac{R}{10  R} $$ 

$$L_2  - 40 = 20 (-1)                \implies   L_2 = 20   dB$$

Physics

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image