## toxicsugar22 5 years ago At a concert By the Who in 1976, the sound level 50 meters from the stag registered 120 decibles. The treshold of pain for the human ear is 90 decibles. Calculate the sound intensity of the Who concert and the sound intenisity of the treshold of pain

1. heisenberg

I think you need to combine the sound intensity level formula and the inverse square law for this guy.

2. toxicsugar22

WILL YOU HELP ME DO THAT

3. anonymous

why inverse square law?

4. toxicsugar22

CAN YOU HELP ME

5. toxicsugar22

6. anonymous
7. toxicsugar22

YEAH THANKS BUT i DONT KNOW HOW TO START IT

8. toxicsugar22

WILL YOU HELP ME STAT=RT THIS PROBLEM PLEASE IM SO STRESSED

9. anonymous

10. toxicsugar22

I DID

11. toxicsugar22

PLEASE i WILL BE GRATEFULL TO YOU

12. toxicsugar22

WILL YOU GO STEP BY STEP WITH ME TO OLVE THIS

13. heisenberg

I will try to help, but I am not too sure. But please, take caps lock off.

14. toxicsugar22

ok

15. heisenberg

$Intensity = \frac{Power}{4*\pi*r^2}$

16. heisenberg

sorry, not 'power' but 'sound wave pressure'

17. toxicsugar22

ok

18. heisenberg

to find P, use this: $P = P_r * 10^\frac{SPL}{20}$ P_r is the reference point

19. heisenberg

SPL = decibel level

20. toxicsugar22

ok

21. toxicsugar22

will you help further

22. toxicsugar22

so i understand

23. toxicsugar22

fr next time

24. heisenberg

What don't you understand?

25. toxicsugar22

calculaed the intensity of the concert and the pain

26. toxicsugar22

can you help

27. heisenberg

yes you can use those two formulas. First calculate the pressure, then you can use that to calculate the intensity.

28. toxicsugar22

yes can u supervise me

29. toxicsugar22

help

30. toxicsugar22

so I plug in 120 for SLP

31. heisenberg

Yes

32. heisenberg

according to wikipedia, P_ref is often regarded as 20 µPa in air, so I would use that for P_r

33. toxicsugar22

SO IT IS P=20*10(120/20)

34. toxicsugar22

IS IT RIGHT

35. heisenberg

yes that'll give you the pressure. then you need to find the intensity from a distance.

36. heisenberg

glad the caps are back.

37. toxicsugar22

so i did 20*10 which is 1200

38. toxicsugar22

then i did 120/20 which is 6

39. heisenberg

no, there is an exponent there: $20*10^\frac{120}{20}$

40. heisenberg

= 20 000 000

41. toxicsugar22

i did that and i DID iT WRONG

42. toxicsugar22

like i have this website from school and it checks my work and I did it wrong

43. toxicsugar22

can u guide me

44. toxicsugar22

again

45. toxicsugar22

srry to bother you

46. toxicsugar22

heisenberg you there

47. heisenberg

what did you get? I get = 636.619772

48. toxicsugar22

i got that also

49. toxicsugar22

it not right

50. toxicsugar22

tAT IS NOT RIGHT HEISENBERG

51. toxicsugar22