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Question : 2 of 180
Marks:
+1,
-0
Solution:
The level of sound is given by
L=10‌log(‌)‌dBLet for
40‌dB sound intensity be
I and for
90‌dB sound intensity be
Ix, then
‌40=10‌log(‌)‌⇒‌‌log(‌)=4 . . . (i)
‌‌ and ‌‌‌90=10‌log(‌)‌⇒‌‌log(‌)=9‌‌ Given, ‌‌‌Ix=xI‌⇒‌‌log(‌)=9‌‌ or ‌‌‌log‌x+log(‌)=9⇒log‌x+4=9‌‌ [from Eq.(i)] ‌⇒log‌x=5⇒x=105
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