Posted by Chris on .
I'm not sure how to calculate this question help me! (Grade 11 Physics)
it's sound intensity... Show me how to do it please! (textbook says answer is 3.5 m)
At close proximity, rustling leaves have a sound intensity of about 1.2 x 10^11 W/m squared. At what distance is the sound at the threshold of hearing (1.0 x 10^12 W/m squared

Physics 
DrBob222,
If we take close proximity to mean about 1 meter, then 1.2 x 10^11*(1)^2 = 1.0 x 10^11*d^2
Solve for d. I get 3.46 m which rounds to 3.5. Check my thinking.