A small speaker delivers 2 W of audio output at what distance from the speaker will one detect 120 dB intensity sound (Given reference intensity = 10-12 W/m2)
see full answer
Your Exam Success, Personally Taken Care Of
1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.
An Intiative by Sri Chaitanya
a
10 cm
b
30 cm
c
40 cm
d
20 cm
answer is C.
(Unlock A.I Detailed Solution for FREE)
Best Courses for You
JEE
NEET
Foundation JEE
Foundation NEET
CBSE
Detailed Solution
Loudness of sound is given by dB=10logI/I0 ⇒120=10logI/I0 ⇒120=10logI×1012 ∴I=1 W/m2 Also , I=P/4πr2 ⇒I=24πr2 ⇒r2=12π ⇒r=12πm=0.399m ⇒r =40 cm